Difference between revisions of "Commercial detection with silences"

Revision as of 22:42, 1 July 2015

Author	Hippo
Description	A python/C++ program based on Mythcommflag-wrapper (thank you Cowbut) that works by detecting short silent periods around commercials.
Supports

Relevance

UK: Works well for Freeview/FreeSat SD/HD,
Australia: Works for Freeview SD/HD,
New Zealand: Works,
Germany: Works

Initial Version (by Hippo)

I tried out the scripts in Mythcommflag-wrapper and they worked well on the Freeview channels I receive but not on the FreeviewHD channels. The reason is that the audio on FreevieHD is an AAC stream and not an MP3 stream. Fixing that would require decoding from AAC and encoding back to MP3 before letting the script analyse the MP3 stream. So I wrote a little C program to analyze an uncompressed audio stream and a Python program to wrap it up and turn the output into a commercial skip list.

To use this

Compile the C program and put it somewhere the Python program can find it. (e.g. /usr/local/bin)
Copy the Python program to somehwere the backend can find it.
Follow the instructions on Mythcommflag-wrapper except the job setting should be 'silence.py %JOBID%'

The python program uses avconv to decode the program file to an AU stream. If you don't have avconv replace it with ffmpeg or mythffmpeg (avconv is the new name for ffmpeg). It upconverts the audio to 6 channels so that it works even when the audio switches around. If you know you only ever get stereo you can replace the 6 with 2 to save a bit of CPU power. It might have to go up in future. Up-converting is better because it's low power and always works whereas down-converting may fail depending on your version of avconv/ffmpeg.

This can do near-realtime commflagging by enabling the backend setting to start commflagging when the recording starts. (mythtv-setup/General/Page9-JobQueueGlobal). The programs mark entries in the cutlist <max-break-setting> after the start of a break is detected so this will be after the commercial break has ended. If you are displaying the programme and get too close to the end you will be in the commercials before they are flagged. C'est la vie.

It's low CPU in that it only decodes the audio stream and since it follows the end of the recording it shouldn't thrash the memory or disk. avconv takes about 2% to decode ITV1-HD on a 1.6GHz Atom Asus motherboard.

Cluster Detecting Version (by dizygotheca)

The basic silence detection algorithm is easily thrown by odd silences that occur within 6 mins of an advert and performs poorly on animations/kids programmes. I was keen to cut adverts out of my kids' shows so I developed an algorithm that detects clusters of silences: adverts are characterised by many silences close together whilst isolated silences within programmes are ignored.

Hippo has provided a good platform for a commflagging script. New features of this version are;

Determine ad breaks from clusters of silences. Solves those occasional glitches caused by silences within programmes and does a pretty good job on animations/kids programmes. Also allows the silence detection to be more sensitive (to pick up short and/or long silences) as rogue ones will be ignored.
Integrates the script with Myth logging. Works well with rsyslog (Mythbuntu). Should also work with file logging but I haven't tested it.
Allows parameters to be varied per-channel and per-programme. Useful for channels with 'noisier' ad breaks, ie. Dave, and regular programmes where the defaults don't suit you.
Sends ad breaks to mythplayer as they are found. If you start watching a prog before it has finished recording then the comm-skipping will still work (assuming you're not too close to real-time).

Algorithm

An advert is defined as a cluster of silences, at least <minbreak> long, that is composed of at least <mindetect> silences that occur within <maxsep> of each other.

In practice, silences are detected as a consecutive series of frames having an average audio power below <threshold> for at least <minquiet>. If the interval between a silence and the previous one is less than <maxsep> then they belong to the same cluster; otherwise they lie in different clusters. Clusters that are shorter than <minbreak> or composed of less than <mindetect> silences are ignored. Adverts are shortened by <padding> on both sides.

Although adverts are reported in real-time, all silences and clusters are stored - I originally envisaged using post-scan analysis to amend the detected adverts. However, so far, this hasn't proved necessary or viable.

Change Summary

silence.cpp replaces mausc.c. New algorithm. Optionally uses Qt/Myth libs in order to send messages to mythplayer.
silence.py replaces mausc-wrapper.py. I've updated the deprecated arg parsing, integrated Myth logging and added channel/prog preset handling. It can reside anywhere but I keep mine in /usr/local/bin. It expects the C++ executables to reside in /usr/local/bin/

Upgrading from previous versions

This version communicates with MythPlayer via the Myth Python bindings. Previous versions communicated directly which (optionally) needed Myth & Qt header files to be installed. If you installed libmyth-dev & libqt4-dev just for this reason then they are no longer needed. However be wary of simply uninstalling them - that may break Myth as they also contain libraries. To remove them correctly you will probably have to reinstall Qt & Myth afterwards. It's safer to leave them installed.

Requirements

Compilation environment (gcc, make) - install package build-essential
libsndfile for reading audio samples - install package libsndfile-dev
Python 2.7 for the new argument parser

Building

Copy silence.cpp, silence.py & Makefile to a new directory and cd there.
Build the silence executable using "make"
Install executables & Python script to /usr/local/bin/ using "sudo make install".
The Makefile works for me using gcc 4.6.3 (Ubuntu 12.04) & Myth 0.26. I'm no expert on C++ standards so earlier versions may need some tinkering.

Notes

I only use Freeview SD, so I downmix my stereo reception to 1 channel to improve performance. Refer to Hippo's comments above regarding the number of channels and update silence.py (kUpmix_Channels) accordingly.
You can reduce the audio sample rate (add "-ar 8000" to the avconv command line) to reduce the data throughput. Ultimately all channels/samples are reduced to a single audio power per frame and I haven't noticed any qualitative difference from this optimisation. However it could affect the mythffmpeg load; if loading/performance is important to you, you may wish to experiment with this. I noticed that this doubles the CPU used by avconv without saving any measurable CPU in silence.cpp.
silence.py uses mythffmpeg but, as Hippo states, you can simply replace with avconv/ffmpeg. I notice no difference.
<minbreak> and <mindetect> do not apply to pre-roll/post-roll (starting/ending) 'adverts'.
Mythplayer will not auto-skip pre-roll/post-roll breaks. When starting playback you need to manually comm-skip to the programme start.
The log information can be initially confusing - bear in mind the algorithmic process when interpreting it. The interval of a silence always relates to the previous silence; the interval reported by a cluster always relates to the previous cluster. Silences report their audio power whereas clusters report the number of silences they contain.
If processing manually, note that silence.py clears any existing comm-skip list on startup. Be aware that this also appears to erase the bookmark (and maybe other mark-ups).
UK commercials are usually 10-60 secs long. However I have seen occasional film trailers that are 2 min long (of constant noise). Thus <maxsep> defaults to 120. If you don't mind the odd trailer then reducing <maxsep> to 60 or 90 would probably reduce erroneous cuts.

Running

Assuming you use the same locations, your 'Advert-detection command' (mythtv-setup/General/Page 8) should be:

 /usr/local/bin/silence.py %JOBID% %VERBOSEMODE% --loglevel debug

You can also run it manually from the command line like this:

 silence.py --chanid 1004 --starttime 20130117220000 --loglevel debug

INFO logging shows details of the clusters/cuts, DEBUG logging also shows details of the detected silences.

My performance of SD content on an ageing ASUS M2NPV-VM/Athlon 3500+:

Flagging a completed recording on an idle system takes 2 min for a 1 hr recording
Flagging whilst recording uses about 2% of cpu

Channel Presets

When run on its own the Python program uses decent defaults that work pretty well.

However it's also possible to specify parameters to use for specific channels or programmes. A preset file defines values that override the defaults according to programme title or channel callsign. Only one preset can apply - the first applicable - so care is needed when deciding the order. The title/callsigns are considered to be Python regular expressions so beware of the meta-characters. The 8th field is ignored and so can be used for comments/notes. Specify a preset file using the --presetfile option, like this:

 /usr/local/bin/silence.py %JOBID% %VERBOSEMODE% --loglevel debug --presetfile /home/eric/.mythtv/silence.preset

Once you understand the logging information you can easily tune your own channels/programmes by experimenting with the --preset option directly from a command line until you get decent results. For example;

 silence.py --chanid=1004 --starttime=20130117220000 --loglevel=debug --preset="-80,,3,,180"

Timezone Issues

As of v0.26 the Myth database uses UTC time. However the Python bindings (used by the script) use localtime by default. Therefore determining the proper starttime argument can be frustrating, as it depends on your timezone and DST. Using an ISO format starttime (YYYY-MM-DDThh:mm:ss+hh:mm) is useful here. For example, in a timezone of UTC+9 both of the following examples will find a recording that started at 9:58pm.

This will allow you to specify a UTC time (as derived from the Myth database 'recorded' table);

 env TZ=UTC silence.py --chanid=1004 --starttime=2013-01-17T12:58:00

Or use local time and add a TZ qualifier;

 silence.py --chanid=1004 --starttime=2013-01-17T21:58:00+09:00

This is my preset file which customises the processing of 4 regular programmes and 'tunes' some channels.

silence.preset

 
# presets for silence.py
# use comma separated values: defaults are used for absent values
# For titles/callsign the name is a python regular expressions, case is ignored.
# Re Metachars are # . ^ $ * + ? { } [ ] \ | ( )
# If a title contains one of these, then escape it (using \) or replace it with full stop
# Names are matched to the START of a title/callsign so "e4" also matches "e4+1"
# First name match is used so put specific presets (ie. programmes) before general ones (channels)
#
# title/callsign, threshold, minquiet, mindetect, minbreak, maxsep, padding
# defaults          -75,       0.16,       6,       120,     120,    0.48,
#
frasier,               ,       0.28,        ,          ,      91,        , long pauses in prog
channel 4 news,        ,       1.00,       1,        55,        ,       0, short advert, many silences
milkshake,             ,       0.48,       8,        60,      61,        , ignore short silences in animation/links
rude tube,             ,       0.32,        ,       180,      61,        , ignore short silences in links

channel 4,             ,       0.24,
more 4,                ,       0.24,
dave,               -71,           ,        ,          ,        ,        , loud silences
quest,                 ,           ,        ,          ,      55,        , short silences, long breaks, short ads
channel 5,             ,       0.24,       2,          ,     300,        , cut news out of films 
itv,                   ,           ,        ,          ,        ,     1.0, long pad for films
film 4,                ,           ,        ,          ,        ,     1.0, long pad for films
bbc,                   ,       0.48,       1,        20,     360,       0, pre/post-roll  
cbeebies,              ,       0.48,       1,        20,     360,       0, pre/post-roll  
cbbc,                  ,       0.48,       1,        20,     360,       0, pre/post-roll

Australian Channel Presets

The following preset file is configured to suit Australian HD and SD Freeview channels. The defaults provided work well for many channels and shows, the exception being Nine's group of channels which require a different audio threshold. No effort has (yet) been made to tune for individual shows.

silence_au.preset

 
# presets for silence.py
# use comma separated values: defaults are used for absent values
# For titles/callsign the name is a python regular expressions, case is ignored.
# Re Metachars are # . ^ $ * + ? { } [ ] \ | ( )
# If a title contains one of these, then escape it (using \) or replace it with full stop
# Names are matched to the START of a title/callsign so "e4" also matches "e4+1"
# First name match is used so put specific presets (ie. programmes) before general ones (channels)
#
# title/callsign, threshold, minquiet, mindetect, minbreak, maxsep, padding
# defaults          -75,       0.16,       6,       120,     120,    0.48,
#
# Defaults for Australian Freeview channels.
NINE DIGITAL,       -73,       0.16,       6,       150,      60,    0.48,
GEM,                -73,       0.16,       5,       120,      60,    0.48,
GO!,                -73,       0.16,       5,       120,      60,    0.48,
7 Digital,          -75,       0.16,       5,       150,      60,    0.48,

#ABC1 - No ads, have not bothered attempting to configure for preroll or postroll.
#ABC News 24 - No ads
#ABC2 - ABC4 - No ads, have not bothered attempting to configure for preroll or postroll.	
#ABC3 - No ads, have not bothered attempting to configure for preroll or postroll.
#7mate – defaults working okay with limited testing
#7TWO – defaults working okay so far
#TEN Digital – defaults working okay so far
#ELEVEN – defaults working okay so far
#ONE – defaults working okay so far
#SBS ONE – defaults working okay with limited testing
#SBS TWO – defaults working okay with limited testing
#SBS HD – defaults working okay with limited testing

German Channel Presets

The following preset file is configured to suit German HD and SD Freeview channels. The defaults provided work well for many channels and shows, the exception being ProSieben which require a different audio threshold and minquiet. Not all channels was tested yet.

silence.preset

 
# presets for silence.py
# use comma separated values: defaults are used for absent values
#
# For titles/callsign the name is a python regular expression, case is ignored.
# Re Metachars are # . ^ $ * + ? { } [ ] \ | ( )
# If a title contains one of these, then escape it (using \) or replace it with full stop
# Names are matched to the START of a title/callsign so "e4" also matches "e4+1"
# First name match is used so put specific presets (ie. programmes) before general ones (channels)
#
# threshold: (float)  silence threshold in dB.
# minquiet : (float)  minimum time for silence detection in seconds.
# mindetect: (float)  minimum number of silences to constitute an advert.
# minlength: (float)  minimum length of advert break in seconds.
# maxsep   : (float)  maximum time between silences in an advert break in seconds.
# padding  : (float)  padding for each cut point in seconds.
#
# title/callsign, threshold, minquiet, mindetect, minlength, maxsep, padding
# defaults      ,       -75,     0.16,         6,       120,    120,    0.48
#

prosieben maxx,-105,,,,,1
prosieben,-90,0.12,,,,1

# channels doing well with defaults
# kabel eins
# sat.1
# rtl austria
# rtl2
# sixx
# super rtl
# vox

Trouble Shooting

If you get "Can't access file <filename> from <SG>" errors then ensure your Storage Group directories (mythtv-setup/Storage Groups) have backslashes on the end. See [[1]]
If your comflagging jobs report 126/127 adverts found, this signifies an error when trying to run the job. Check the file permissions for the executables.

Code

silence.cpp

silence.cpp

// Based on mausc.c by Tinsel Phipps.
// v1.0 Roger Siddons
// v2.0 Roger Siddons: Flag clusters asap, fix segfaults, optional headers
// v3.0 Roger Siddons: Remove lib dependencies & commfree
// v4.0 Kill process argv[1] when idle for 30 seconds.
// v4.1 Fix averaging overflow
// v4.2 Unblock the alarm signal so the job actually finishes.
// Public domain. Requires libsndfile
// Detects commercial breaks using clusters of audio silences

#include <cstdlib>
#include <cmath>
#include <cerrno>
#include <climits>
#include <deque>
#include <sndfile.h>
#include <unistd.h>
#include <signal.h>

typedef unsigned frameNumber_t;
typedef unsigned frameCount_t;

// Output to python wrapper requires prefix to indicate level
#define DELIMITER "@" // must correlate with python wrapper
char prefixdebug[7] = "debug" DELIMITER;
char prefixinfo[6]  = "info" DELIMITER;
char prefixerr[5]   = "err" DELIMITER;
char prefixcut[5]   = "cut" DELIMITER;

void error(const char* mesg, bool die = true)
{
    printf("%s%s\n", prefixerr, mesg);
    if (die)
        exit(1);
}

pid_t tail_pid = 0;
void watchdog(int sig)
{
    if (0 != tail_pid)
        kill(tail_pid, SIGTERM);
}

namespace Arg
// Program argument management
{
const float kvideoRate = 25.0;  // sample rate in fps (maps time to frame count)
const frameCount_t krateInMins = kvideoRate * 60; // frames per min
unsigned useThreshold;          // Audio level of silence
frameCount_t useMinQuiet;       // Minimum length of a silence to register
unsigned useMinDetect;          // Minimum number of silences that constitute an advert
frameCount_t useMinLength;      // adverts must be at least this long
frameCount_t useMaxSep;         // silences must be closer than this to be in the same cluster
frameCount_t usePad;            // padding for each cut

void usage()
{
    error("Usage: silence <tail_pid> <threshold> <minquiet> <mindetect> <minlength> <maxsep> <pad>", false);
    error("<tail_pid> : (int)    Process ID to be killed after idle timeout.", false);
    error("<threshold>: (float)  silence threshold in dB.", false);
    error("<minquiet> : (float)  minimum time for silence detection in seconds.", false);
    error("<mindetect>: (float)  minimum number of silences to constitute an advert.", false);
    error("<minlength>: (float)  minimum length of advert break in seconds.", false);
    error("<maxsep>   : (float)  maximum time between silences in an advert break in seconds.", false);
    error("<pad>      : (float)  padding for each cut point in seconds.", false);
    error("AU format audio is expected on stdin.", false);
    error("Example: silence 4567 -75 0.1 5 60 90 1 < audio.au");
}

void parse(int argc, char **argv)
// Parse args and convert to useable values (frames)
{
    if (8 != argc)
        usage();

    float argThreshold; // db
    float argMinQuiet; // secs
    float argMinDetect;
    float argMinLength; // secs
    float argMaxSep; // secs
    float argPad; // secs

    /* Load options. */
    if (1 != sscanf(argv[1], "%d", &tail_pid))
        error("Could not parse tail_pid option into a number");
    if (1 != sscanf(argv[2], "%f", &argThreshold))
        error("Could not parse threshold option into a number");
    if (1 != sscanf(argv[3], "%f", &argMinQuiet))
        error("Could not parse minquiet option into a number");
    if (1 != sscanf(argv[4], "%f", &argMinDetect))
        error("Could not parse mindetect option into a number");
    if (1 != sscanf(argv[5], "%f", &argMinLength))
        error("Could not parse minlength option into a number");
    if (1 != sscanf(argv[6], "%f", &argMaxSep))
        error("Could not parse maxsep option into a number");
    if (1 != sscanf(argv[7], "%f", &argPad))
        error("Could not parse pad option into a number");

    /* Scale threshold to integer range that libsndfile will use. */
    useThreshold = rint(INT_MAX * pow(10, argThreshold / 20));

    /* Scale times to frames. */
    useMinQuiet  = ceil(argMinQuiet * kvideoRate);
    useMinDetect = (int)argMinDetect;
    useMinLength = ceil(argMinLength * kvideoRate);
    useMaxSep    = rint(argMaxSep * kvideoRate + 0.5);
    usePad       = rint(argPad * kvideoRate + 0.5);

    printf("%sThreshold=%.1f, MinQuiet=%.2f, MinDetect=%.1f, MinLength=%.1f, MaxSep=%.1f, Pad=%.2f\n",
           prefixdebug, argThreshold, argMinQuiet, argMinDetect, argMinLength, argMaxSep, argPad);
    printf("%sFrame rate is %.2f, Detecting silences below %d that last for at least %d frames\n",
           prefixdebug, kvideoRate, useThreshold, useMinQuiet);
    printf("%sClusters are composed of a minimum of %d silences closer than %d frames and must be\n",
           prefixdebug, useMinDetect, useMaxSep);
    printf("%slonger than %d frames in total. Cuts will be padded by %d frames\n",
           prefixdebug, useMinLength, usePad);
    printf("%s< preroll, > postroll, - advert, ? too few silences, # too short, = comm flagged\n", prefixdebug);
    printf("%s           Start - End    Start - End      Duration         Interval    Level/Count\n", prefixinfo);
    printf("%s          frame - frame (mmm:ss-mmm:ss) frame (mm:ss.s)  frame (mmm:ss)\n", prefixinfo);
}
}

class Silence
// Defines a silence
{
public:
    enum state_t {progStart, detection, progEnd};
    static const char state_log[3];

    const state_t state;       // type of silence
    const frameNumber_t start; // frame of start
    frameNumber_t end;         // frame of end
    frameCount_t length;       // number of frames
    frameCount_t interval;     // frames between end of last silence & start of this one
    double power;              // average power level

    Silence(frameNumber_t _start, double _power = 0, state_t _state = detection)
        : state(_state), start(_start), end(_start), length(1), interval(0), power(_power) {}

    void extend(frameNumber_t frame, double _power)
    // Define end of the silence
    {
        end = frame;
        length = frame - start + 1;
        // maintain running average power: = (oldpower * (newlength - 1) + newpower)/ newlength
        power += (_power - power)/length;
    }
};
// c++0x doesn't allow initialisation within class
const char Silence::state_log[3] = {'<', ' ', '>'};

class Cluster
// A cluster of silences
{
private:
    void setState()
    {
        if (this->start->start == 1)
            state = preroll;
        else if (this->end->state == Silence::progEnd)
            state = postroll;
        else if (length < Arg::useMinLength)
            state = tooshort;
        else if (silenceCount < Arg::useMinDetect)
            state = toofew;
        else
            state = advert;
    }

public:
    // tooshort..unset are transient states - they may be updated, preroll..postroll are final
    enum state_t {tooshort, toofew, unset, preroll, advert, postroll};
    static const char state_log[6];

    static frameNumber_t completesAt; // frame where the most recent cluster will complete

    state_t state;          // type of cluster
    const Silence* start;   // first silence
    Silence* end;           // last silence
    frameNumber_t padStart, padEnd; // padded cluster start/end frames
    unsigned silenceCount;  // number of silences
    frameCount_t length;    // number of frames
    frameCount_t interval;  // frames between end of last cluster and start of this one

    Cluster(Silence* s) : state(unset), start(s), end(s), silenceCount(1), length(s->length), interval(0)
    {
        completesAt = end->end + Arg::useMaxSep; // finish cluster <maxsep> beyond silence end
        setState();
        // pad everything except pre-rolls
        padStart = (state == preroll ? 1 : start->start + Arg::usePad);
    }

    void extend(Silence* _end)
    // Define end of a cluster
    {
        end = _end;
        silenceCount++;
        length = end->end - start->start + 1;
        completesAt = end->end + Arg::useMaxSep; // finish cluster <maxsep> beyond silence end
        setState();
        // pad everything except post-rolls
        padEnd = end->end - (state == postroll ? 0 : Arg::usePad);
    }
};
// c++0x doesn't allow initialisation within class
const char Cluster::state_log[6] = {'#', '?', '.', '<', '-', '>'};
frameNumber_t Cluster::completesAt = 0;

class ClusterList
// Manages a list of detected silences and a list of assigned clusters
{
protected:
    // list of detected silences
    std::deque<Silence*> silence;

    // list of deduced clusters of the silences
    std::deque<Cluster*> cluster;

public:
    Silence* insertStartSilence()
    // Inserts a fake silence at the front of the silence list
    {
        // create a single frame silence at frame 1 and insert it at front
        Silence* ref = new Silence(1, 0, Silence::progStart);
        silence.push_front(ref);
        return ref;
    }

    void addSilence(Silence* newSilence)
    // Adds a silence detection to the end of the silence list
    {
        // set interval between this & previous silence/prog start
        newSilence->interval = newSilence->start
                - (silence.empty() ? 1 : silence.back()->end - 1);
        // store silence
        silence.push_back(newSilence);
    }

    void addCluster(Cluster* newCluster)
    // Adds a cluster to end of the cluster list
    {
        // set interval between new cluster & previous one/prog start
        newCluster->interval = newCluster->start->start
                - (cluster.empty() ? 1 : cluster.back()->end->end - 1);
        // store cluster
        cluster.push_back(newCluster);
    }
};

Silence* currentSilence; // the silence currently being detected/built
Cluster* currentCluster; // the cluster currently being built
ClusterList* clist;      // List of completed silences & clusters

void report(const char* err,
            const char type,
            const char* msg1,
            const frameNumber_t start,
            const frameNumber_t end,
            const frameNumber_t interval,
            const int power)
// Logs silences/clusters/cuts in a standard format
{
    frameCount_t duration = end - start + 1;

    printf("%s%c %7s %6d-%6d (%3d:%02ld-%3d:%02ld), %4d (%2d:%04.1f), %5d (%3d:%02ld), [%7d]\n",
           err, type, msg1, start, end,
           (start+13) / Arg::krateInMins, lrint(start / Arg::kvideoRate) % 60,
           (end+13) / Arg::krateInMins, lrint(end / Arg::kvideoRate) % 60,
           duration, (duration+1) / Arg::krateInMins, fmod(duration / Arg::kvideoRate, 60),
           interval, (interval+13) / Arg::krateInMins, lrint(interval / Arg::kvideoRate) % 60, power);
}

void processSilence()
// Process a silence detection
{
    // ignore detections that are too short
    if (currentSilence->state == Silence::detection && currentSilence->length < Arg::useMinQuiet)
    {
        // throw it away
        delete currentSilence;
        currentSilence = NULL;
    }
    else
    {
        // record new silence
        clist->addSilence(currentSilence);

        // assign it to a cluster
        if (currentCluster)
        {
            // add to existing cluster
            currentCluster->extend(currentSilence);
        }
        else if (currentSilence->interval <= Arg::useMaxSep) // only possible for very first silence
        {
            // First silence is close to prog start so extend cluster to the start
            // by inserting a fake silence at prog start and starting the cluster there
            currentCluster = new Cluster(clist->insertStartSilence());
            currentCluster->extend(currentSilence);
        }
        else
        {
            // this silence is the start of a new cluster
            currentCluster = new Cluster(currentSilence);
        }
        report(prefixdebug, currentSilence->state_log[currentSilence->state], "Silence",
               currentSilence->start, currentSilence->end,
               currentSilence->interval, currentSilence->power);

        // silence is now owned by the list, start looking for next
        currentSilence = NULL;
    }
}

void processCluster()
// Process a completed cluster
{
    // record new cluster
    clist->addCluster(currentCluster);

    report(prefixinfo, currentCluster->state_log[currentCluster->state], "Cluster",
           currentCluster->start->start, currentCluster->end->end,
           currentCluster->interval, currentCluster->silenceCount);

    // only flag clusters at final state
    if (currentCluster->state > Cluster::unset)
        report(prefixcut, '=', "Cut", currentCluster->padStart, currentCluster->padEnd, 0, 0);

    // cluster is now owned by the list, start looking for next
    currentCluster = NULL;
}

int main(int argc, char **argv)
// Detect silences and allocate to clusters
{
    // Remove logging prefixes if writing to terminal
    if (isatty(1))
        prefixcut[0] = prefixinfo[0] = prefixdebug[0] = prefixerr[0] = '\0';

    // flush output buffer after every line
    setvbuf(stdout, NULL, _IOLBF, 0);

    Arg::parse(argc, argv);

    /* Check the input is an audiofile. */
    SF_INFO metadata;
    SNDFILE* input = sf_open_fd(STDIN_FILENO, SFM_READ, &metadata, SF_FALSE);
    if (NULL == input) {
        error("libsndfile error:", false);
        error(sf_strerror(NULL));
    }

    /* Allocate data buffer to contain audio data from one video frame. */
    const size_t frameSamples = metadata.channels * metadata.samplerate / Arg::kvideoRate;

    int* samples = (int*)malloc(frameSamples * sizeof(int));
    if (NULL == samples)
        error("Couldn't allocate memory");

    // create silence/cluster list
    clist = new ClusterList();

    // Kill head of pipeline if timeout happens.
    signal(SIGALRM, watchdog);
    sigset_t intmask;
    sigemptyset(&intmask);
    sigaddset(&intmask, SIGALRM);
    sigprocmask(SIG_UNBLOCK, &intmask, NULL);
    alarm(30);

    // Process the input one frame at a time and process cuts along the way.
    frameNumber_t frames = 0;
    while (frameSamples == static_cast<size_t>(sf_read_int(input, samples, frameSamples)))
    {
        alarm(30);
        frames++;

        // determine average audio level in this frame
        unsigned long long avgabs = 0;
        for (unsigned i = 0; i < frameSamples; i++)
            avgabs += abs(samples[i]);
        avgabs = avgabs / frameSamples;

        // check for a silence
        if (avgabs < Arg::useThreshold)
        {
            if (currentSilence)
            {
                // extend current silence
                currentSilence->extend(frames, avgabs);
            }
            else // transition to silence
            {
                // start a new silence
                currentSilence = new Silence(frames, avgabs);
            }
        }
        else if (currentSilence) // transition out of silence
        {
            processSilence();
        }
        // in noise: check for cluster completion
        else if (currentCluster && frames > currentCluster->completesAt)
        {
            processCluster();
        }
    }
    // Complete any current silence (prog may have finished in silence)
    if (currentSilence)
    {
        processSilence();
    }
    // extend any cluster close to prog end
    if (currentCluster && frames <= currentCluster->completesAt)
    {
        // generate a silence at prog end and extend cluster to it
        currentSilence = new Silence(frames, 0, Silence::progEnd);
        processSilence();
    }
    // Complete any final cluster
    if (currentCluster)
    {
        processCluster();
    }
}

silence.py

silence.py

#!/usr/bin/env python
# Build a skiplist from silence in the audio track.
# v1.0 Roger Siddons
# v2.0 Fix progid for job/player messages
# v3.0 Send player messages via Python
# v3.1 Fix commflag status, pad preset. Improve style & make Python 3 compatible
# v4.0 silence.cpp will kill the head of the pipeline (tail) when recording finished
# v4.1 Use unicode for foreign chars
# v4.2 Prevent BE writeStringList errors
# v5.0 Improve exception handling/logging. Fix player messages (0.26+ only)

import MythTV
import os
import subprocess
import argparse
import collections
import re
import sys

kExe_Silence = '/usr/local/bin/silence'
kUpmix_Channels = '6' # Change this to 2 if you never have surround sound in your recordings.

class MYLOG(MythTV.MythLog):
  "A specialised logger"

  def __init__(self, db):
    "Initialise logging"
    MythTV.MythLog.__init__(self, '', db)

  def log(self, msg, level = MythTV.MythLog.INFO):
    "Log message"
    # prepend string to msg so that rsyslog routes it to mythcommflag.log logfile
    MythTV.MythLog.log(self, MythTV.MythLog.COMMFLAG, level, 'mythcommflag: ' + msg.rstrip('\n'))

class PRESET:
  "Manages the presets (parameters passed to the detection algorithm)"

  # define arg ordering and default values
  argname = ['thresh', 'minquiet', 'mindetect', 'minbreak', 'maxsep', 'pad']
  argval  = [  -75,       0.16,        6,          120,       120,    0.48]
  # dictionary holds value for each arg
  argdict = collections.OrderedDict(list(zip(argname, argval)))

  def _validate(self, k, v):
    "Converts arg input from string to float or None if invalid/not supplied"
    if v is None or v == '':
      return k, None
    try:
      return k, float(v)
    except ValueError:
      self.logger.log('Preset ' + k + ' (' + str(v) + ') is invalid - will use default',
        MYLOG.ERR)
      return k, None

  def __init__(self, _logger):
    "Initialise preset manager"
    self.logger = _logger

  def getFromArg(self, line):
    "Parses preset values from command-line string"
    self.logger.log('Parsing presets from "' + line + '"', MYLOG.DEBUG)
    if line:  # ignore empty string
      vals = [i.strip() for i in line.split(',')]  # split individual params
      # convert supplied values to float & match to appropriate arg name
      validargs = list(map(self._validate, self.argname, vals[0:len(self.argname)]))
      # remove missing/invalid values from list & replace default values with the rest
      self.argdict.update(v for v in validargs if v[1] is not None)

  def getFromFile(self, filename, title, callsign):
    "Gets preset values from a file"
    self.logger.log('Using preset file "' + filename + '"', MYLOG.DEBUG)
    try:
      with open(filename) as presets:
        for rawline in presets:
          line = rawline.strip()
          if line and (not line.startswith('#')):  # ignore empty & comment lines
            vals = [i.strip() for i in line.split(',')]  # split individual params
            # match preset name to recording title or channel
            pattern = re.compile(vals[0], re.IGNORECASE)
            if pattern.match(title) or pattern.match(callsign):
              self.logger.log('Using preset "' + line.strip() + '"')
              # convert supplied values to float & match to appropriate arg name
              validargs = list(map(self._validate, self.argname,
                         vals[1:1 + len(self.argname)]))
              # remove missing/invalid values from list &
              # replace default values with the rest
              self.argdict.update(v for v in validargs if v[1] is not None)
              break
        else:
          self.logger.log('No preset found for "' + title.encode('utf-8') + '" or "' + callsign.encode('utf-8') + '"')
    except IOError:
      self.logger.log('Presets file "' + filename + '" not found', MYLOG.ERR)
    return self.argdict

  def getValues(self):
    "Returns params as a list of strings"
    return [str(i) for i in list(self.argdict.values())]


def main():
  "Commflag a recording"
  try:
    # define options
    parser = argparse.ArgumentParser(description='Commflagger')
    parser.add_argument('--preset', help='Specify values as "Threshold, MinQuiet, MinDetect, MinLength, MaxSep, Pad"')
    parser.add_argument('--presetfile', help='Specify file containing preset values')
    parser.add_argument('--chanid', type=int, help='Use chanid for manual operation')
    parser.add_argument('--starttime', help='Use starttime for manual operation')
    parser.add_argument('--dump', action="store_true", help='Generate stack trace of exception')
    parser.add_argument('jobid', nargs='?', help='Myth job id')

    # must set up log attributes before Db locks them
    MYLOG.loadArgParse(parser)
    MYLOG._setmask(MYLOG.COMMFLAG)

    # parse options
    args = parser.parse_args()

    # connect to backend
    db = MythTV.MythDB()
    logger = MYLOG(db)
    be = MythTV.BECache(db=db)

    logger.log('')	# separate jobs in logfile
    if args.jobid:
      logger.log('Starting job %s'%args.jobid, MYLOG.INFO)
      job = MythTV.Job(args.jobid, db)
      chanid = job.chanid
      starttime = job.starttime
    elif args.chanid and args.starttime:
      job = None
      chanid = args.chanid
      try:
        # only 0.26+
        starttime = MythTV.datetime.duck(args.starttime)
      except AttributeError:
        starttime = args.starttimeaction="store_true"
    else:
      logger.log('Both --chanid and -starttime must be specified', MYLOG.ERR)
      sys.exit(1)

    # mythplayer update message uses a 'chanid_utcTimeAsISODate' format to identify recording
    try:
      # only 0.26+
      utc = starttime.asnaiveutc()
    except AttributeError:
      utc = starttime

    progId = '%d_%s'%(chanid, str(utc).replace(' ', 'T'))

    # get recording
    logger.log('Seeking chanid %s, starttime %s' %(chanid, starttime), MYLOG.INFO)
    rec = MythTV.Recorded((chanid, starttime), db)
    channel = MythTV.Channel(chanid, db)

    logger.log('Processing: ' + channel.callsign.encode('utf-8') + ', ' + str(rec.starttime)
      + ', "' + rec.title.encode('utf-8') + ' - ' + rec.subtitle.encode('utf-8')+ '"')

    sg = MythTV.findfile(rec.basename, rec.storagegroup, db)
    if sg is None:
      logger.log("Can't access file %s from %s"%(rec.basename, rec.storagegroup), MYLOG.ERR)
      try:
        job.update({'status': job.ERRORED, 'comment': "Couldn't access file"})
      except AttributeError : pass
      sys.exit(1)

    # create params with default values
    param = PRESET(logger)
    # read any supplied presets
    if args.preset:
      param.getFromArg(args.preset)
    elif args.presetfile:  # use preset file
      param.getFromFile(args.presetfile, rec.title, channel.callsign)

    # Pipe file through ffmpeg to extract uncompressed audio stream. Keep going till recording is finished.
    infile = os.path.join(sg.dirname, rec.basename)
    p1 = subprocess.Popen(["tail", "--follow", "--bytes=+1", infile], stdout=subprocess.PIPE)
    p2 = subprocess.Popen(["mythffmpeg", "-loglevel", "quiet", "-i", "pipe:0",
                "-f", "au", "-ac", kUpmix_Channels, "-"],
                stdin=p1.stdout, stdout=subprocess.PIPE)
    # Pipe audio stream to C++ silence which will spit out formatted log lines
    p3 = subprocess.Popen([kExe_Silence, "%d" % p1.pid] + param.getValues(), stdin=p2.stdout,
                stdout=subprocess.PIPE)

    # Purge any existing skip list and flag as in-progress
    rec.commflagged = 2
    rec.markup.clean()
    rec.update()

    # Process log output from C++ silence
    breaks = 0
    level = {'info': MYLOG.INFO, 'debug': MYLOG.DEBUG, 'err': MYLOG.ERR}
    while True:
      line = p3.stdout.readline()
      if line:
        flag, info = line.split('@', 1)
        if flag == 'cut':
          # extract numbers from log line
          numbers = re.findall('\d+', info)
          logger.log(info)
          # mark advert in database
          rec.markup.append(int(numbers[0]), rec.markup.MARK_COMM_START, None)
          rec.markup.append(int(numbers[1]), rec.markup.MARK_COMM_END, None)
          rec.update()
          breaks += 1
          # send new advert skiplist to MythPlayers
          skiplist = ['%d:%d,%d:%d'%(x, rec.markup.MARK_COMM_START, y, rec.markup.MARK_COMM_END)
                   for x, y in rec.markup.getskiplist()]
          mesg = 'COMMFLAG_UPDATE %s %s'%(progId, ','.join(skiplist))
#         logger.log('  Sending %s'%mesg,  MYLOG.DEBUG)
          result = be.backendCommand("MESSAGE[]:[]" + mesg)
          if result != 'OK':
            logger.log('Sending update message to backend failed, response = %s, message = %s'% (result, mesg), MYLOG.ERR)
        elif flag in level:
          logger.log(info, level.get(flag))
        else:  # unexpected prefix
          # use warning for unexpected log levels
          logger.log(flag, MYLOG.WARNING)
      else:
        break

    # Signal comflagging has finished
    rec.commflagged = 1
    rec.update()

    logger.log('Detected %s adverts.' % breaks)
    try:
      job.update({'status': 272, 'comment': 'Detected %s adverts.' % breaks})
    except AttributeError : pass

    # Finishing too quickly can cause writeStringList/socket errors in the BE. (pre-0.28 only?)
    # A short delay prevents this
    import time
    time.sleep(1)

  except Exception as e:
    # get exception before we generate another
    import traceback
    exc_type, exc_value, frame = sys.exc_info()
    # get stacktrace as a list
    stack = traceback.format_exception(exc_type, exc_value, frame)

    # set status
    status = 'Failed due to: "%s"'%e
    try:
      logger.log(status, MYLOG.ERR)
    except : pass
    try:
      job.update({'status': job.ERRORED, 'comment': 'Failed.'})
    except : pass

    # populate stack trace with vars
    try:
      if args.dump:
        # insert the frame local vars after each frame trace
        # i is the line index following the frame trace; 0 is the trace mesg, 1 is the first code line
        i = 2
        while frame is not None:
          # format local vars
          vars = []
          for name, var in frame.tb_frame.f_locals.iteritems():
            try:
              text = '%s' % var
              # truncate vars that are too long
              if len(text) > 1000:
                text = text[:1000] + '...'

            except Exception as e: # some var defs may be incomplete
              text = '<Unknown due to: %s>'%e
            vars.append('@ %s = %s'%(name, text))
          # insert local stack contents after code trace line
          stack.insert(i, '\n'.join(['@-------------'] + vars + ['@-------------\n']))
          # advance over our insertion & the next code trace line
          i += 2
          frame = frame.tb_next
        logger.log('\n'.join(stack), MYLOG.ERR)
    except : pass
    sys.exit(1)

if __name__ == '__main__':
  main()

Makefile

Makefile

CC        = g++
CFLAGS    = -c -Wall -std=c++0x
LIBPATH   = -L/usr/lib
TARGETDIR = /usr/local/bin

.PHONY: clean install

all: silence
	
silence: silence.o
	$(CC) silence.o -o $@ $(LIBPATH) -lsndfile

.cpp.o:
	$(CC) $(CFLAGS) $< -o $@

install: silence silence.py
	install -p -t $(TARGETDIR) $^

clean: 
	-rm -f silence *.o

Difference between revisions of "Commercial detection with silences"

Revision as of 22:42, 1 July 2015

Contents

Relevance

Initial Version (by Hippo)

Cluster Detecting Version (by dizygotheca)

Algorithm

Change Summary

Upgrading from previous versions

Requirements

Building

Notes

Running

Channel Presets

Timezone Issues

Australian Channel Presets

German Channel Presets

Trouble Shooting

Code

silence.cpp

silence.py

Makefile

Navigation menu

Personal tools

Namespaces

Variants

Views

More

Search

Wiki Navigation

Official Resources

Tools

Print/export

@@ Line 1: / Line 1: @@
 {{Script info
 |author=Hippo
-|short=A replacement for mythcommflag that works by detecting short silent periods around commercials.
+|short=An alternative to mythcommflag that works by detecting short silent periods around commercials.
-|long=A python program based on [[Mythcommflag-wrapper]] (thank you Cowbut) that can be used on UK FreeviewHD channels and probably others.
+|long=A python/C++ program based on [[Mythcommflag-wrapper]] (thank you Cowbut) that works by detecting short silent periods around commercials.
 |category=Scripts
-|S25=yes|S26=yes}}
+|S25=yes|S26=yes|S27=yes}}
-== Original version ==
+== Relevance ==
+* UK: Works well for Freeview/FreeSat SD/HD,
+* Australia: Works for Freeview SD/HD,
+* New Zealand: Works,
+* Germany: Works
+== Initial Version (by Hippo) ==
 I tried out the scripts in [[Mythcommflag-wrapper]] and they worked well on the Freeview channels I receive but not on the FreeviewHD channels. The reason is that the audio on FreevieHD is an AAC stream and not an MP3 stream. Fixing that would require decoding from AAC and encoding back to MP3 before letting the script analyse the MP3 stream. So I wrote a little C program to analyze an uncompressed audio stream and a Python program to wrap it up and turn the output into a commercial skip list.
 To use this
-* Compile the two C programs and put them somewhere the Python program can find it. (e.g. /usr/local/bin)
+* Compile the C program and put it somewhere the Python program can find it. (e.g. /usr/local/bin)
 * Copy the Python program to somehwere the backend can find it.
-* Follow the instructions on [[Mythcommflag-wrapper]] except the job setting should be 'mausc-wrapper.py %JOBID%'
+* Follow the instructions on [[Mythcommflag-wrapper]] except the job setting should be 'silence.py %JOBID%'
 The python program uses avconv to decode the program file to an AU stream. If you don't have avconv replace it with ffmpeg or mythffmpeg (avconv is the new name for ffmpeg). It upconverts the audio to 6 channels so that it works even when the audio switches around. If you know you only ever get stereo you can replace the 6 with 2 to save a bit of CPU power. It might have to go up in future. Up-converting is better because it's low power and always works whereas down-converting may fail depending on your version of avconv/ffmpeg.
@@ Line 18: / Line 24: @@
 This can do near-realtime commflagging by enabling the backend setting to start commflagging when the recording starts. (mythtv-setup/General/Page9-JobQueueGlobal). The programs mark entries in the cutlist <max-break-setting> after the start of a break is detected so this will be after the commercial break has ended. If you are displaying the programme and get too close to the end you will be in the commercials before they are flagged. C'est la vie.
-It's low CPU in that it only decodes the audio stream and since it follows the end of the recording it shouldn't thrash the memory or disk. avconv takes about 2% to decode ITV1-HD on a 1.6GHz Atom Asus motherboard. catagrower takes about 1% and could be a lot better if made less portable.
+It's low CPU in that it only decodes the audio stream and since it follows the end of the recording it shouldn't thrash the memory or disk. avconv takes about 2% to decode ITV1-HD on a 1.6GHz Atom Asus motherboard.
-{{Code box|catagrower.c|
-<pre>
-/* Copyright 2012 Crackers Phipps. */
-/* Public domain. */
-/* Compile with
-   gcc -std=c99 -O catagrower.c -o catagrower
-*/
-/* This program will stop when the file has not grown for this many seconds. */
-#define TIMEOUT 60
-/* MythTV files are often large. */
-#define _FILE_OFFSET_BITS 64
-#include <stdio.h>
-#include <stdlib.h>
-#include <fcntl.h>
-#include <unistd.h>
-static void usage(const char *name) {
-  fprintf(stderr, "Usage: %s <file>\n", name);
-  fprintf(stderr, "<file>: file to be monitored.\n");
-  fprintf(stderr, "The contents of the file will be copied to stdout.\n");
-  fprintf(stderr, "Copying will stop when the file has stopped growing.\n");
-}
-int main(int argc, char **argv) {
-  /* Check usage. */
-  if (2 != argc) {
-    usage(argv[0]);
-    exit(1);
-  }
-  /* Load options. */
-  int fd;
-  if (-1 == (fd = open(argv[1], O_RDONLY))) {
-    fprintf(stderr, "Could not open %s for reading.\n", argv[1]);
-    usage(argv[0]);
-    exit(2);
-  }
-#define BUFFSIZE 4096
-  int timer = TIMEOUT;
-  char buffer[BUFFSIZE];
-  int bytes;
-  while (timer > 0) {
-    while (0 != (bytes = read(fd, buffer, BUFFSIZE))) {
-      write (STDOUT_FILENO, buffer, bytes);
-      timer = TIMEOUT;
-    }
-    sleep(1);
-    timer--;
-  }
-  return 0;
-}
-</pre>
-}}
-{{Code box|mausc.c|
-<pre>
-/* Copyright 2013 Tinsel Phipps. */
-/* Public domain. Links with libsndfile which is GPL. */
-/* Compile with
-   gcc -std=c99 -O mausc.c -o mausc -lsndfile -lm
-   You may need the libsndfile-dev package installed.
-*/
-#include <stdlib.h>
-#include <math.h>
-#include <sndfile.h>
-#include <errno.h>
-#include <unistd.h>
-#include <limits.h>
-static void usage(const char *name) {
+== Cluster Detecting Version (by dizygotheca)==
-  fprintf(stderr, "Usage: %s <threshold> <min> <max> <rate>\n", name);
-  fprintf(stderr, "<threshold>: silence threshold in dB.\n");
-  fprintf(stderr, "<min>: minimum time for silence detection in seconds.\n");
-  fprintf(stderr, "<max>: maximum length of breaks in seconds.\n");
-  fprintf(stderr, "<rate>: frame rate of video.\n");
-  fprintf(stderr, "An AU format file should be fed into this program.\n");
-  fprintf(stderr, "Example: %s -70 0.15 400 25 < audio.au\n", name);
-}
-int main(int argc, char **argv) {
-  /* Check usage. */
-  if (5 != argc) {
-    usage(argv[0]);
-    exit(1);
-  }
-  /* Load options. */
-  float threshold, min, max, rate;
-  if (1 != sscanf(argv[1], "%f", &threshold)) {
-    fprintf(stderr, "Could not parse threshold option into a number.\n");
-    usage(argv[0]);
-    exit(2);
-  }
-  if (1 != sscanf(argv[2], "%f", &min)) {
-    fprintf(stderr, "Could not parse min option into a number.\n");
-    usage(argv[0]);
-    exit(2);
-  }
-  if (1 != sscanf(argv[3], "%f", &max)) {
-    fprintf(stderr, "Could not parse max option into a number.\n");
-    usage(argv[0]);
-    exit(2);
-  }
-  if (1 != sscanf(argv[4], "%f", &rate)) {
-    fprintf(stderr, "Could not parse rate option into a number.\n");
-    usage(argv[0]);
-    exit(2);
-  }
-  /* Scale threshold to integer range that libsndfile will use. */
-  threshold = INT_MAX * pow(10, threshold / 20);
-  /* Scale times to frames. */
-  min = min * rate;
-  max = max * rate;
-  /* Check the input is an audiofile. */
-  SNDFILE *input;
-  SF_INFO metadata;
-  input = sf_open_fd(STDIN_FILENO, SFM_READ, &metadata, SF_FALSE);
-  if (NULL == input) {
-    sf_perror(NULL);
-    return sf_error(NULL);
-  }
-  /* Allocate data buffer to contain audio data from one video frame. */
-  size_t frameSamples = metadata.channels * metadata.samplerate / rate;
-  int *samples;
-  samples = malloc(frameSamples * sizeof(int));
-  if (NULL == samples) {
-    perror(NULL);
-    return errno;
-  }
-  /* Process the file one frame at a time and process cuts along the way. */
-  int frames = 0;
-  int silent = 0;
-  int last_silent = 0;
-  int gapend = 0;
-  int gapstart = 0;
-  int first_gapstart = 0;
-  while (frameSamples == sf_read_int(input, samples, frameSamples)) {
-    frames++;
-    int maxabs = 0;
-    for (unsigned i = 0; i < frameSamples; i++) {
-      samples[i] = abs(samples[i]);
-      maxabs = (maxabs > samples[i]) ? maxabs : samples[i];
-    }
-    last_silent = silent;
-    silent = (maxabs < threshold);
-    /* Remember first transition to silence. */
-    if (silent && !gapstart) {
-      gapstart = frames;
-    }
-    /* Store last transition out of silence. */
-    if (!silent && last_silent) {
-      /* Make sure it is long enough. */
-      if (frames > gapstart + min) {
-        gapend = frames;
-        if (!first_gapstart) {
-          first_gapstart = gapstart;
-        }
-      }
-      gapstart = 0;
-    }
-    /* Create a skip when max frames have passed. */
-    if (first_gapstart && gapend && frames > first_gapstart + max) {
-      printf("%d %d\n", first_gapstart, gapend);
-      fflush(stdout);
-      gapstart = 0;
-      gapend = 0;
-      first_gapstart = 0;
-    }
-  }
-  /* At end of file can have an unprocessed gap. */
-  if (first_gapstart) {
-    if (first_gapstart == gapstart) {
-      gapend = frames;
-    }
-    printf("%d %d\n", first_gapstart, gapend);
-  }
-  return sf_close(input);
-}
-</pre>
-}}
-{{Code box|mausc-wrapper|
-<pre>
-#!/usr/bin/env python
-# Build a skiplist from silence in the audio track.
-# Based on http://www.mythtv.org/wiki/Transcode_wrapper_stub
-from MythTV import MythDB, Job, Recorded, findfile, MythLog
-from os import path
-from subprocess import Popen, PIPE
-from optparse import OptionParser
-def runjob(jobid=None, chanid=None, starttime=None):
-    # Tunable settings (would like to retrieve per channel from the database)
-    thresh = -70 # Silence threshold in dB.
-    minquiet = 0.15 # Minimum time for silence detection in seconds.
-    maxbreak = 400 # Maximum length of adverts breaks.
-    rate = 25 # Frame rate of video. (should be automatic)
-    db = MythDB()
-    if jobid:
-        job = Job(jobid, db=db)
-        chanid = job.chanid
-        starttime = job.starttime
-    try:
-        rec = Recorded((chanid, starttime), db=db)
-    except:
-        if jobid:
-            job.update({'status':job.ERRORED,
-                        'comment':'ERROR: Could not find recording.'})
-        else:
-            print 'Could not find recording.'
-        exit(1)
-    # Get program handle in standard format.
-    starttime = rec.starttime
-    chanid = rec.chanid
-    sg = findfile(rec.basename, rec.storagegroup, db=db)
-    if sg is None:
-        if jobid:
-            job.update({'status':job.ERRORED,
-                        'comment':'ERROR: Local access to recording not found.'})
-        else:
-            print 'Local access to recording not found.'
-        exit(1)
-    infile = path.join(sg.dirname, rec.basename)
-    # Purge any existing skip list.
-    rec.markup.clean()
-    rec.commflagged = 0
-    rec.update()
-    # Write out the file contents and keep going till recording is finished.
-    p1 = Popen(["catagrower", infile],
-               stdout = PIPE)
-    # Pipe through avconv to extract uncompressed audio stream.
-    p2 = Popen(["avconv", "-v", "8", "-i", "pipe:0", "-f", "au", "-ac", "6", "-"],
-               stdin = p1.stdout, stdout = PIPE)
-    # Pipe to mausc which will spit out a list of breaks.
-    p3 = Popen(["mausc", str(thresh), str(minquiet), str(maxbreak), str(rate)],
-               stdin = p2.stdout, stdout = PIPE)
-    # Store breaks in the database.
-    breaks = 0
-    while 1:
-        line = p3.stdout.readline()
-        if not line:
-            break
-        start, end = line.split()
-        rec.markup.append(start, rec.markup.MARK_COMM_START, None)
-        rec.markup.append(end, rec.markup.MARK_COMM_END, None)
-        rec.commflagged = 1
-        rec.update()
-        breaks = breaks + 1
-        if jobid is None:
-            print 'Got a break at frame %s' % start
-    if jobid:
-        job.update({'status':272,
-                    'comment':'Audio commflag detected %s breaks.' % breaks
-                    })
-    else:
-        print 'Audio commflag detected %s breaks.' % breaks
-def main():
-    parser = OptionParser(usage="usage: %prog [options] [jobid]")
-    parser.add_option('--chanid', action='store', type='int',
-                      dest='chanid', help='Use chanid for manual operation')
-    parser.add_option('--starttime', action='store', type='string',
-                      dest='stime', help='Use starttime for manual operation')
-    MythLog.loadOptParse(parser)
-    opts, args = parser.parse_args()
-    if len(args) == 1:
-        runjob(jobid=args[0])
-    elif opts.chanid and opts.stime:
-        runjob(chanid=opts.chanid, starttime=opts.stime)
-    else:
-        print 'Script must be provided either jobid, or chanid and starttime.'
-        parser.print_help()
-        exit(1)
-if __name__ == '__main__':
-    main()
-</pre>
-}}
-== Cluster Detecting Version ==
 The basic silence detection algorithm is easily thrown by odd silences that occur within 6 mins of an advert and performs poorly on animations/kids programmes. I was keen to cut adverts out of my kids' shows so I developed an algorithm that detects clusters of silences: adverts are characterised by many silences close together whilst isolated silences within programmes are ignored.
-Hippo has provided a good platform for a commflagging script. New features of my version are;
+Hippo has provided a good platform for a commflagging script. New features of this version are;
 *Determine ad breaks from clusters of silences. Solves those occasional glitches caused by silences within programmes and does a pretty good job on animations/kids programmes. Also allows the silence detection to be more sensitive (to pick up short and/or long silences) as rogue ones will be ignored.
 *Integrates the script with Myth logging. Works well with rsyslog (Mythbuntu). Should also work with file logging but I haven't tested it.
@@ Line 329: / Line 36: @@
 === Algorithm ===
-An advert is defined as a cluster of silences, at least <minbreak> long, that is composed of at least <mindetect> silences all within <maxsep> of each other.
+An advert is defined as a cluster of silences, at least <minbreak> long, that is composed of at least <mindetect> silences that occur within <maxsep> of each other.
 In practice, silences are detected as a consecutive series of frames having an average audio power below <threshold> for at least <minquiet>. If the interval between a silence and the previous one is less than <maxsep> then they belong to the same cluster; otherwise they lie in different clusters. Clusters that are shorter than <minbreak> or composed of less than <mindetect> silences are ignored. Adverts are shortened by <padding> on both sides.
-Although adverts are reported in real-time, all silences and clusters are stored - I originally envisaged using post-scan analysis to amend the detected adverts. However, so far, this hasn't proved necessary or viable.
-=== Building/Change Summary ===
+Although adverts are reported in real-time, all silences and clusters are stored - I originally envisaged using post-scan analysis to amend the detected adverts. However, so far, this hasn't proved necessary or viable.
-*catagrower.cpp has minor mods to take its timeout from an arg. This is to allow the script to be run manually from the command line.
-*silence.cpp replaces mausc.c. New algorithm. This now depends on Qt/Myth libs in order to send messages to mythplayer.
+=== Change Summary ===
-*silence.py replaces mausc-wrapper.py. I've updated the deprecated arg parsing, integrated Myth logging and added channel/prog preset handling. It can reside anywhere but I keep mine in /usr/local/bin. It expects the C++ executables to reside in /usr/local/bin/ though.
+*silence.cpp replaces mausc.c. New algorithm. Optionally uses Qt/Myth libs in order to send messages to mythplayer.
-*Build the C++ files using the Makefile (ie. "sudo make"). This will put the executables in /usr/local/bin/. The Makefile works for me using gcc 4.6.3 (Ubuntu 12.04) & Myth 0.26. I'm no expert on C++ standards so earlier versions may need some tinkering.
+*silence.py replaces mausc-wrapper.py. I've updated the deprecated arg parsing, integrated Myth logging and added channel/prog preset handling. It can reside anywhere but I keep mine in /usr/local/bin. It expects the C++ executables to reside in /usr/local/bin/
+=== Upgrading from previous versions ===
+This version communicates with MythPlayer via the Myth Python bindings. Previous versions communicated directly which (optionally) needed Myth & Qt header files to be installed. If you installed libmyth-dev & libqt4-dev just for this reason then they are no longer needed. However be wary of simply uninstalling them - that may break Myth as they also contain libraries. To remove them correctly you will probably have to reinstall Qt & Myth afterwards. It's safer to leave them installed.
+=== Requirements ===
+*Compilation environment (gcc, make) - install package build-essential
+*[http://www.mega-nerd.com/libsndfile/ libsndfile] for reading audio samples - install package libsndfile-dev
+*Python 2.7 for the new argument parser
+=== Building ===
+*Copy silence.cpp, silence.py & Makefile to a new directory and cd there.
+*Build the silence executable using "make"
+*Install executables & Python script to /usr/local/bin/ using "sudo make install".
+*The Makefile works for me using gcc 4.6.3 (Ubuntu 12.04) & Myth 0.26. I'm no expert on C++ standards so earlier versions may need some tinkering.
 === Notes ===
 *I only use Freeview SD, so I downmix my stereo reception to 1 channel to improve performance. Refer to Hippo's comments above regarding the number of channels and update silence.py (kUpmix_Channels) accordingly.
-*I also reduce the audio sample rate (silence.py line 177, "-ar 8000") to reduce the data throughput. Ultimately all channels/samples are reduced to a single audio power per frame and I haven't noticed any qualitative difference from this optimisation. However it could affect the mythffmpeg load; if loading/performance is important to you, you may wish to experiment with this.
+*You can reduce the audio sample rate (add "-ar 8000" to the avconv command line) to reduce the data throughput. Ultimately all channels/samples are reduced to a single audio power per frame and I haven't noticed any qualitative difference from this optimisation. However it could affect the mythffmpeg load; if loading/performance is important to you, you may wish to experiment with this. I noticed that this doubles the CPU used by avconv without saving any measurable CPU in silence.cpp.
-*silence.py utilises mythffmpeg but, as Hippo states, you can simply replace with avconv/ffmpeg. I notice no difference.
+*silence.py uses mythffmpeg but, as Hippo states, you can simply replace with avconv/ffmpeg. I notice no difference.
 *<minbreak> and <mindetect> do not apply to pre-roll/post-roll (starting/ending) 'adverts'.
-*All programmes will be processed. However, if it originates from a channel marked as comm-free, only pre-roll and post-roll breaks will be detected. This is useful for finding the start of BBC programmes.
 *Mythplayer will not auto-skip pre-roll/post-roll breaks. When starting playback you need to manually comm-skip to the programme start.
 *The log information can be initially confusing - bear in mind the algorithmic process when interpreting it. The interval of a silence always relates to the previous silence; the interval reported by a cluster always relates to the previous cluster. Silences report their audio power whereas clusters report the number of silences they contain.
-*If processing manually, note that the Python will clear any existing comm-skip list on startup. Be aware that this also appears to erase the bookmark (and maybe other mark-ups).
+*If processing manually, note that silence.py clears any existing comm-skip list on startup. Be aware that this also appears to erase the bookmark (and maybe other mark-ups).
-*UK commercials are usually 10-60 secs long. However I have found occasional film trailers that are 2 min long (of constant noise). Thus <maxsep> defaults to 120. If you don't mind the odd trailer then reducing <maxsep> to 60 or 90 would probably reduce erroneous cuts.
+*UK commercials are usually 10-60 secs long. However I have seen occasional film trailers that are 2 min long (of constant noise). Thus <maxsep> defaults to 120. If you don't mind the odd trailer then reducing <maxsep> to 60 or 90 would probably reduce erroneous cuts.
 === Running ===
-Assuming you use the same locations, your Advert-detection command should be:
+Assuming you use the same locations, your 'Advert-detection command' (mythtv-setup/General/Page 8) should be:
-   /usr/local/bin/silence.py %JOBID% %VERBOSELEVEL% --loglevel debug
+   /usr/local/bin/silence.py %JOBID% %VERBOSEMODE% --loglevel debug
 You can also run it manually from the command line like this:
    silence.py --chanid 1004 --starttime 20130117220000 --loglevel debug
-INFO logging reports details of the clusters/cuts, DEBUG logging also reports details of the detected silences.
+INFO logging shows details of the clusters/cuts, DEBUG logging also shows details of the detected silences.
+My performance of SD content on an ageing ASUS M2NPV-VM/Athlon 3500+:
+*Flagging a completed recording on an idle system takes 2 min for a 1 hr recording
+*Flagging whilst recording uses about 2% of cpu
 === Channel Presets ===
@@ Line 363: / Line 86: @@
 However it's also possible to specify parameters to use for specific channels or programmes. A preset file defines values that override the defaults according to programme title or channel callsign. Only one preset can apply - the first applicable - so care is needed when deciding the order. The title/callsigns are considered to be Python regular expressions so beware of the meta-characters. The 8th field is ignored and so can be used for comments/notes. Specify a preset file using the --presetfile option, like this:
-   /usr/local/bin/silence.py %JOBID% %VERBOSELEVEL% --loglevel debug --presetfile /home/eric/.mythtv/silence.preset
+   /usr/local/bin/silence.py %JOBID% %VERBOSEMODE% --loglevel debug --presetfile /home/eric/.mythtv/silence.preset
+Once you understand the logging information you can easily tune your own channels/programmes by experimenting with the --preset option directly from a command line until you get decent results. For example;
+  silence.py --chanid=1004 --starttime=20130117220000 --loglevel=debug --preset="-80,,3,,180"
+=== Timezone Issues ===
+As of v0.26 the Myth database uses UTC time. However the Python bindings (used by the script) use localtime by default. Therefore determining the proper starttime argument can be frustrating, as it depends on your timezone and DST. Using an ISO format starttime (YYYY-MM-DDThh:mm:ss+hh:mm) is useful here. For example, in a timezone of UTC+9 both of the following examples will find a recording that started at 9:58pm.
+This will allow you to specify a UTC time (as derived from the Myth database 'recorded' table);
+  env TZ=UTC silence.py --chanid=1004 --starttime=2013-01-17T12:58:00
+Or use local time and add a TZ qualifier;
+  silence.py --chanid=1004 --starttime=2013-01-17T21:58:00+09:00
 This is my preset file which customises the processing of 4 regular programmes and 'tunes' some channels.
@@ Line 397: / Line 132: @@
 }}
-Once you understand the logging information you can easily tune your own channels/programmes by experimenting with the --preset option directly from a command line until you get decent results. For example;
+=== Australian Channel Presets ===
-  silence.py --chanid 1004 --starttime 20130117220000 --loglevel debug --preset "-80,,3,,180"
+The following preset file is configured to suit Australian HD and SD Freeview channels. The defaults provided work well for many channels and shows, the exception being Nine's group of channels which require a different audio threshold. No effort has (yet) been made to tune for individual shows.
-{{Code box|catagrower.cpp|
+{{Code box|silence_au.preset|
 <pre>
-/* Copyright 2012 Crackers Phipps. */
+# presets for silence.py
-/* Public domain. */
+# use comma separated values: defaults are used for absent values
-/* Compile with
+# For titles/callsign the name is a python regular expressions, case is ignored.
-    gcc -std=c99 -O catagrower.c -o catagrower
+# Re Metachars are # . ^ $ * + ? { } [ ] \ | ( )
-*/
+# If a title contains one of these, then escape it (using \) or replace it with full stop
+# Names are matched to the START of a title/callsign so "e4" also matches "e4+1"
+# First name match is used so put specific presets (ie. programmes) before general ones (channels)
+#
+# title/callsign, threshold, minquiet, mindetect, minbreak, maxsep, padding
+# defaults          -75,       0.16,       6,       120,     120,    0.48,
+#
+# Defaults for Australian Freeview channels.
+NINE DIGITAL,       -73,       0.16,       6,       150,      60,    0.48,
+GEM,                -73,       0.16,       5,       120,      60,    0.48,
+GO!,                -73,       0.16,       5,       120,      60,    0.48,
+Digital,          -75,       0.16,       5,       150,      60,    0.48,
-/* MythTV files are often large. */
+#ABC1 - No ads, have not bothered attempting to configure for preroll or postroll.
-#define _FILE_OFFSET_BITS 64
+#ABC News 24 - No ads
+#ABC2 - ABC4 - No ads, have not bothered attempting to configure for preroll or postroll.
+#ABC3 - No ads, have not bothered attempting to configure for preroll or postroll.
+#7mate – defaults working okay with limited testing
+#7TWO – defaults working okay so far
+#TEN Digital – defaults working okay so far
+#ELEVEN – defaults working okay so far
+#ONE – defaults working okay so far
+#SBS ONE – defaults working okay with limited testing
+#SBS TWO – defaults working okay with limited testing
+#SBS HD – defaults working okay with limited testing
+</pre>
+}}
-#include <stdio.h>
-#include <stdlib.h>
-#include <fcntl.h>
-#include <unistd.h>
-static void usage(const char *name) {
+=== German Channel Presets ===
-  fprintf(stderr, "Usage: %s <file> <timeout>\n", name);
-  fprintf(stderr, "<file>   : file to be monitored.\n");
-  fprintf(stderr, "<timeout>: secs to wait for input.\n");
-  fprintf(stderr, "The contents of the file will be copied to stdout.\n");
-  fprintf(stderr, "Copying will stop when the file has stopped growing.\n");
-}
-int main(int argc, char **argv) {
+The following preset file is configured to suit German HD and SD Freeview channels. The defaults provided work well for many channels and shows, the exception being ProSieben which require a different audio threshold and minquiet. Not all channels was tested yet.
-  /* Check usage. */
+{{Code box|silence.preset|
-  if (3 != argc) {
+<pre>
-    usage(argv[0]);
+# presets for silence.py
-    exit(1);
+# use comma separated values: defaults are used for absent values
-   }
+#
+# For titles/callsign the name is a python regular expression, case is ignored.
+# Re Metachars are # . ^ $ * + ? { } [ ] \ | ( )
+# If a title contains one of these, then escape it (using \) or replace it with full stop
+# Names are matched to the START of a title/callsign so "e4" also matches "e4+1"
+# First name match is used so put specific presets (ie. programmes) before general ones (channels)
+#
+# threshold: (float)  silence threshold in dB.
+# minquiet : (float)  minimum time for silence detection in seconds.
+# mindetect: (float)  minimum number of silences to constitute an advert.
+# minlength: (float)  minimum length of advert break in seconds.
+# maxsep   : (float)  maximum time between silences in an advert break in seconds.
+# padding  : (float)  padding for each cut point in seconds.
+#
+# title/callsign, threshold, minquiet, mindetect, minlength, maxsep, padding
+# defaults      ,       -75,     0.16,         6,       120,    120,    0.48
+#
-  /* Load options. */
+prosieben maxx,-105,,,,,1
-  int fd;
+prosieben,-90,0.12,,,,1
-  if (-1 == (fd = open(argv[1], O_RDONLY))) {
-    fprintf(stderr, "Could not open %s for reading.\n", argv[1]);
-    usage(argv[0]);
-    exit(2);
-  }
-  const int timeout = atoi(argv[2]);
-#define BUFFSIZE 4096
+# channels doing well with defaults
-  int timer = timeout;
+# kabel eins
-  char buffer[BUFFSIZE];
+# sat.1
-  int bytes;
+# rtl austria
-  while (timer > 0) {
+# rtl2
-    while (0 != (bytes = read(fd, buffer, BUFFSIZE))) {
+# sixx
-      if (-1 == write (STDOUT_FILENO, buffer, bytes)){
+# super rtl
-          fprintf(stderr, "Write failed.\n");
+# vox
-          exit(3);
-        }
-      timer = timeout;
-    }
-    sleep(1);
-    timer--;
-  }
-  return 0;
-}
 </pre>
 }}
+=== Trouble Shooting ===
+*If you get "Can't access file <filename> from <SG>" errors then ensure your Storage Group directories (mythtv-setup/Storage Groups) have backslashes on the end. See [[http://www.gossamer-threads.com/lists/mythtv/users/531768#531768]]
+*If your comflagging jobs report 126/127 adverts found, this signifies an error when trying to run the job. Check the file permissions for the executables.
+=== Code ===
+==== silence.cpp ====
 {{Code box|silence.cpp|
 <pre>
 // Based on mausc.c by Tinsel Phipps.
 // v1.0 Roger Siddons
-// Public domain. Requires libsndfile, libQtCore, libmythbase-0.x, libmyth-0.x
+// v2.0 Roger Siddons: Flag clusters asap, fix segfaults, optional headers
+// v3.0 Roger Siddons: Remove lib dependencies & commfree
+// v4.0 Kill process argv[1] when idle for 30 seconds.
+// v4.1 Fix averaging overflow
+// v4.2 Unblock the alarm signal so the job actually finishes.
+// Public domain. Requires libsndfile
 // Detects commercial breaks using clusters of audio silences
+#include <cstdlib>
+#include <cmath>
+#include <cerrno>
+#include <climits>
+#include <deque>
 #include <sndfile.h>
 #include <unistd.h>
-#include <mythcorecontext.h>
+#include <signal.h>
-#include <mythcontext.h>
-#include <mythversion.h>
-#include <programtypes.h>
-#include <QCoreApplication>
-#define DELIMITER '@' // must correlate with python wrapper
 typedef unsigned frameNumber_t;
 typedef unsigned frameCount_t;
+// Output to python wrapper requires prefix to indicate level
+#define DELIMITER "@" // must correlate with python wrapper
+char prefixdebug[7] = "debug" DELIMITER;
+char prefixinfo[6]  = "info" DELIMITER;
+char prefixerr[5]   = "err" DELIMITER;
+char prefixcut[5]   = "cut" DELIMITER;
+void error(const char* mesg, bool die = true)
+{
+    printf("%s%s\n", prefixerr, mesg);
+    if (die)
+        exit(1);
+}
+pid_t tail_pid = 0;
+void watchdog(int sig)
+{
+    if (0 != tail_pid)
+        kill(tail_pid, SIGTERM);
+}
+namespace Arg
+// Program argument management
+{
+const float kvideoRate = 25.0;  // sample rate in fps (maps time to frame count)
+const frameCount_t krateInMins = kvideoRate * 60; // frames per min
+unsigned useThreshold;          // Audio level of silence
+frameCount_t useMinQuiet;       // Minimum length of a silence to register
+unsigned useMinDetect;          // Minimum number of silences that constitute an advert
+frameCount_t useMinLength;      // adverts must be at least this long
+frameCount_t useMaxSep;         // silences must be closer than this to be in the same cluster
+frameCount_t usePad;            // padding for each cut
+void usage()
+{
+    error("Usage: silence <tail_pid> <threshold> <minquiet> <mindetect> <minlength> <maxsep> <pad>", false);
+    error("<tail_pid> : (int)    Process ID to be killed after idle timeout.", false);
+    error("<threshold>: (float)  silence threshold in dB.", false);
+    error("<minquiet> : (float)  minimum time for silence detection in seconds.", false);
+    error("<mindetect>: (float)  minimum number of silences to constitute an advert.", false);
+    error("<minlength>: (float)  minimum length of advert break in seconds.", false);
+    error("<maxsep>   : (float)  maximum time between silences in an advert break in seconds.", false);
+    error("<pad>      : (float)  padding for each cut point in seconds.", false);
+    error("AU format audio is expected on stdin.", false);
+    error("Example: silence 4567 -75 0.1 5 60 90 1 < audio.au");
+}
+void parse(int argc, char **argv)
+// Parse args and convert to useable values (frames)
+{
+    if (8 != argc)
+        usage();
+    float argThreshold; // db
+    float argMinQuiet; // secs
+    float argMinDetect;
+    float argMinLength; // secs
+    float argMaxSep; // secs
+    float argPad; // secs
+    /* Load options. */
+    if (1 != sscanf(argv[1], "%d", &tail_pid))
+        error("Could not parse tail_pid option into a number");
+    if (1 != sscanf(argv[2], "%f", &argThreshold))
+        error("Could not parse threshold option into a number");
+    if (1 != sscanf(argv[3], "%f", &argMinQuiet))
+        error("Could not parse minquiet option into a number");
+    if (1 != sscanf(argv[4], "%f", &argMinDetect))
+        error("Could not parse mindetect option into a number");
+    if (1 != sscanf(argv[5], "%f", &argMinLength))
+        error("Could not parse minlength option into a number");
+    if (1 != sscanf(argv[6], "%f", &argMaxSep))
+        error("Could not parse maxsep option into a number");
+    if (1 != sscanf(argv[7], "%f", &argPad))
+        error("Could not parse pad option into a number");
+    /* Scale threshold to integer range that libsndfile will use. */
+    useThreshold = rint(INT_MAX * pow(10, argThreshold / 20));
+    /* Scale times to frames. */
+    useMinQuiet  = ceil(argMinQuiet * kvideoRate);
+    useMinDetect = (int)argMinDetect;
+    useMinLength = ceil(argMinLength * kvideoRate);
+    useMaxSep    = rint(argMaxSep * kvideoRate + 0.5);
+    usePad       = rint(argPad * kvideoRate + 0.5);
+    printf("%sThreshold=%.1f, MinQuiet=%.2f, MinDetect=%.1f, MinLength=%.1f, MaxSep=%.1f, Pad=%.2f\n",
+           prefixdebug, argThreshold, argMinQuiet, argMinDetect, argMinLength, argMaxSep, argPad);
+    printf("%sFrame rate is %.2f, Detecting silences below %d that last for at least %d frames\n",
+           prefixdebug, kvideoRate, useThreshold, useMinQuiet);
+    printf("%sClusters are composed of a minimum of %d silences closer than %d frames and must be\n",
+           prefixdebug, useMinDetect, useMaxSep);
+    printf("%slonger than %d frames in total. Cuts will be padded by %d frames\n",
+           prefixdebug, useMinLength, usePad);
+    printf("%s< preroll, > postroll, - advert, ? too few silences, # too short, = comm flagged\n", prefixdebug);
+    printf("%s           Start - End    Start - End      Duration         Interval    Level/Count\n", prefixinfo);
+    printf("%s          frame - frame (mmm:ss-mmm:ss) frame (mm:ss.s)  frame (mmm:ss)\n", prefixinfo);
+}
+}
 class Silence
-// A detected silence
+// Defines a silence
 {
 public:
-     enum state_t {detected, progStart, progEnd, beyondEnd};
+     enum state_t {progStart, detection, progEnd};
-     static const char state_log[5];
+     static const char state_log[3];
-    frameNumber_t start;   // frame of start
-    frameNumber_t end;     // frame of end
-    frameCount_t length;   // number of frames
-    frameCount_t interval; // frames between end of last silence & start of this one
-    double power;          // average power level
-    state_t state;         // type of silence
-     Silence() : start(0), end(0), length(0), interval(0), power(0), state(detected) {}
+     const state_t state;       // type of silence
+    const frameNumber_t start; // frame of start
+    frameNumber_t end;         // frame of end
+    frameCount_t length;       // number of frames
+    frameCount_t interval;     // frames between end of last silence & start of this one
+    double power;              // average power level
-     Silence(frameNumber_t _start,
+     Silence(frameNumber_t _start, double _power = 0, state_t _state = detection)
-            frameNumber_t _end,
+        : state(_state), start(_start), end(_start), length(1), interval(0), power(_power) {}
-            state_t _state) : start(_start), end(_end), length(_end - _start + 1),
-        interval(0), power(0), state(_state) {}
-    void restart(frameNumber_t frame, double _power, state_t _state = detected)
-    // Define start of a silence
-    {
-        start = end = frame;
-        length = 1;
-        interval = 0;
-        power = _power;
-        state = _state;
-    }
      void extend(frameNumber_t frame, double _power)
-     // Define end of a silence
+     // Define end of the silence
      {
          end = frame;
          length = frame - start + 1;
-         // maintain running average power, allowing for missing frames
+         // maintain running average power: = (oldpower * (newlength - 1) + newpower)/ newlength
-        // = (oldpower * (newlength - 1) + newpower)/ newlength
-        // a missing frame is assigned a power of the current average
          power += (_power - power)/length;
      }
 };
 // c++0x doesn't allow initialisation within class
-const char Silence::state_log[5] = {' ', '<', '>', 'v'};
+const char Silence::state_log[3] = {'<', ' ', '>'};
 class Cluster
 // A cluster of silences
 {
+private:
+    void setState()
+    {
+        if (this->start->start == 1)
+            state = preroll;
+        else if (this->end->state == Silence::progEnd)
+            state = postroll;
+        else if (length < Arg::useMinLength)
+            state = tooshort;
+        else if (silenceCount < Arg::useMinDetect)
+            state = toofew;
+        else
+            state = advert;
+    }
 public:
-     enum state_t {unset, preroll, advert, tooshort, toofew, postroll};
+    // tooshort..unset are transient states - they may be updated, preroll..postroll are final
+     enum state_t {tooshort, toofew, unset, preroll, advert, postroll};
      static const char state_log[6];
-     Silence* start;         // first silence
+     static frameNumber_t completesAt; // frame where the most recent cluster will complete
+    state_t state;          // type of cluster
+    const Silence* start;   // first silence
      Silence* end;           // last silence
+    frameNumber_t padStart, padEnd; // padded cluster start/end frames
      unsigned silenceCount;  // number of silences
      frameCount_t length;    // number of frames
      frameCount_t interval;  // frames between end of last cluster and start of this one
-    state_t state;
-    Cluster() : start(0), end(0), silenceCount(0), length(0), interval(0), state(unset) {}
-     void restart(Silence* _start)
+     Cluster(Silence* s) : state(unset), start(s), end(s), silenceCount(1), length(s->length), interval(0)
-    // Define start of a cluster
      {
-         start = end =_start;
+         completesAt = end->end + Arg::useMaxSep; // finish cluster <maxsep> beyond silence end
-         silenceCount = 1;
+         setState();
-         length = _start->length;
+         // pad everything except pre-rolls
-         state = unset;
+         padStart = (state == preroll ? 1 : start->start + Arg::usePad);
      }
@@ Line 556: / Line 417: @@
          end = _end;
          silenceCount++;
-         length = _end->end - start->start + 1;
+         length = end->end - start->start + 1;
+        completesAt = end->end + Arg::useMaxSep; // finish cluster <maxsep> beyond silence end
+        setState();
+        // pad everything except post-rolls
+        padEnd = end->end - (state == postroll ? 0 : Arg::usePad);
      }
 };
 // c++0x doesn't allow initialisation within class
-const char Cluster::state_log[6] = {'.', '<', '-', '#', '?', '>'};
+const char Cluster::state_log[6] = {'#', '?', '.', '<', '-', '>'};
+frameNumber_t Cluster::completesAt = 0;
 class ClusterList
-// Stores a list of detected silences and a list of assigned clusters
+// Manages a list of detected silences and a list of assigned clusters
 {
 protected:
-    const unsigned useMinDetect;
-    const frameCount_t useMinLength;
      // list of detected silences
-     QList<Silence*> silence;
+     std::deque<Silence*> silence;
-     // list of deduced clusters of silences
+     // list of deduced clusters of the silences
-     QList<Cluster*> cluster;
+     std::deque<Cluster*> cluster;
 public:
-    ClusterList(unsigned minDetect, frameCount_t minLength)
-        : useMinDetect(minDetect), useMinLength(minLength) {}
-    ~ClusterList()
-    {
-        // release contents of lists
-        qDeleteAll(silence);
-        qDeleteAll(cluster);
-    }
-    Silence* addSilence(Silence& newSilence)
-    // Adds a silence detection to the end of the silence list
-    {
-        Silence* ref = NULL;
-        // set interval between this & previous good silence
-        if (Silence* prev = getLastSilence())
-            newSilence.interval = newSilence.start - prev->end - 1;
-        else // no previous
-            newSilence.interval = newSilence.start - 1;
-        // do not store fake silence
-        if (newSilence.state != Silence::beyondEnd)
-        {
-            // store silence in ClusterList
-            ref = new Silence(newSilence);
-            silence.push_back(ref);
-        }
-        return ref;
-    }
      Silence* insertStartSilence()
      // Inserts a fake silence at the front of the silence list
      {
          // create a single frame silence at frame 1 and insert it at front
-         Silence* ref = new Silence(1, 1, Silence::progStart);
+         Silence* ref = new Silence(1, 0, Silence::progStart);
          silence.push_front(ref);
          return ref;
      }
-     Silence* getLastSilence()
+     void addSilence(Silence* newSilence)
-     // Returns previous silence in list
+     // Adds a silence detection to the end of the silence list
      {
-         if (silence.isEmpty())
+         // set interval between this & previous silence/prog start
-            return NULL;
+        newSilence->interval = newSilence->start
-         else
+                - (silence.empty() ? 1 : silence.back()->end - 1);
-            return silence.last();
+         // store silence
+        silence.push_back(newSilence);
      }
-     Cluster* addCluster(Cluster& newCluster)
+     void addCluster(Cluster* newCluster)
      // Adds a cluster to end of the cluster list
      {
-         // ignore empty cluster at prog end
+         // set interval between new cluster & previous one/prog start
-        if (newCluster.end->state == Silence::progEnd
+        newCluster->interval = newCluster->start->start
-                && newCluster.length == 1)
+                 - (cluster.empty() ? 1 : cluster.back()->end->end - 1);
-        {
+        // store cluster
-            // delete prog end silence as it serves no purpose
+        cluster.push_back(newCluster);
-            silence.removeLast();
-            return NULL;
-        }
-        else
-        {
-            // link to previous cluster
-            // set interval between new cluster & previous one (or prog start)
-            if (cluster.isEmpty())
-                newCluster.interval = newCluster.start->start - 1;
-            else
-                 newCluster.interval = newCluster.start->start - cluster.last()->end->end - 1;
-            // set state
-            if (newCluster.start->start == 1)
-                newCluster.state = Cluster::preroll;
-            else if (newCluster.end->state == Silence::progEnd)
-                newCluster.state = Cluster::postroll;
-            else if (newCluster.length < useMinLength)
-                newCluster.state = Cluster::tooshort;
-            else if (newCluster.silenceCount < useMinDetect)
-                newCluster.state = Cluster::toofew;
-            else
-                newCluster.state = Cluster::advert;
-            // store cluster in ClusterList
-            Cluster* ref = new Cluster(newCluster);
-            cluster.push_back(ref);
-            return ref;
-        }
      }
 };
-// List of completed silences & clusters
+Silence* currentSilence; // the silence currently being detected/built
-ClusterList* clist;
+Cluster* currentCluster; // the cluster currently being built
+ClusterList* clist;      // List of completed silences & clusters
-// the items currently being detected/built
-Silence currentSilence;
-Cluster currentCluster;
-// Player update message
-QString updateMessage;
-// Audio detection settings from args
-// Audio level of silence
-int useThreshold;
-// Minimum length of a silence to register
-frameCount_t useMinQuiet;
-// Minimum number of silences that constitute an advert
-unsigned useMinDetect;
-// adverts must be at least this long
-frameCount_t useMinLength;
-// silence detections must be closer together than this to be in the same cluster
-frameCount_t useMaxSep;
-// padding for each cut
-frameCount_t usePad;
-// sample rate (maps time to frame count)
-const float kvideoRate = 25.0; // fps
-const frameCount_t krateInMins = kvideoRate * 60; // frames per min
-// true if prog originates from a comm-free channel
-int commfree; // bool
-static void usage(const char *name) {
-    printf("err%cUsage: %s <threshold> <minquiet> <mindetect> <minlength> <maxsep> <pad> <commfree> <progid>\n",
-        DELIMITER, name);
-    printf("err%c<threshold>: (float)  silence threshold in dB.\n", DELIMITER);
-    printf("err%c<minquiet> : (float)  minimum time for silence detection in seconds.\n", DELIMITER);
-    printf("err%c<mindetect>: (float)  minimum number of silences to constitute an advert.\n", DELIMITER);
-    printf("err%c<minlength>: (float)  minimum length of advert break in seconds.\n", DELIMITER);
-    printf("err%c<maxsep>   : (float)  maximum time between silences in an advert break in seconds.\n", DELIMITER);
-    printf("err%c<pad>      : (float)  padding for each cut point in seconds.\n", DELIMITER);
-    printf("err%c<commfree> : (int)    1 if prog is comm-free, 0 otherwise.\n", DELIMITER);
-    printf("err%c<progid>   : (string) chan_starttime of program (for player updates).\n", DELIMITER);
-    printf("err%cAn AU format file should be fed into this program.\n", DELIMITER);
-    printf("err%cExample: %s -75 0.1 5 60 90 0 1004_20121003090000 < audio.au\n", DELIMITER, name);
-}
-void parseArgs(int argc, char **argv)
-// Parse args and convert to useable values (frames)
-{
-    /* Check usage. */
-    if (9 != argc) {
-        usage(argv[0]);
-        exit(1);
-    }
-    float argThreshold; // db
-    float argMinQuiet; // secs
-    float argMinDetect;
-    float argMinLength; // secs
-    float argMaxSep; // secs
-    float argPad; // secs
-    char progid[100];
-    /* Load options. */
-    if (1 != sscanf(argv[1], "%f", &argThreshold)) {
-        printf("err%cCould not parse threshold option into a number", DELIMITER);
-        exit(2);
-    }
-    if (1 != sscanf(argv[2], "%f", &argMinQuiet)) {
-        printf("err%cCould not parse minquiet option into a number", DELIMITER);
-        exit(2);
-    }
-    if (1 != sscanf(argv[3], "%f", &argMinDetect)) {
-        printf("err%cCould not parse mindetect option into a number", DELIMITER);
-        exit(2);
-    }
-    if (1 != sscanf(argv[4], "%f", &argMinLength)) {
-        printf("err%cCould not parse minlength option into a number", DELIMITER);
-        exit(2);
-    }
-    if (1 != sscanf(argv[5], "%f", &argMaxSep)) {
-        printf("err%cCould not parse maxsep option into a number", DELIMITER);
-        exit(2);
-    }
-    if (1 != sscanf(argv[6], "%f", &argPad)) {
-        printf("err%cCould not parse pad option into a number", DELIMITER);
-        exit(2);
-    }
-    if (1 != sscanf(argv[7], "%d", &commfree)) {
-        printf("err%cCould not parse commfree option into a number", DELIMITER);
-        exit(2);
-    }
-    if (1 != sscanf(argv[8], "%s", progid)) {
-        printf("err%cCould not parse progid option into a string", DELIMITER);
-        exit(2);
-    }
-    /* Scale threshold to integer range that libsndfile will use. */
-    useThreshold = rint(INT_MAX * pow(10, argThreshold / 20));
-    /* Scale times to frames. */
-    useMinQuiet  = ceil(argMinQuiet * kvideoRate);
-    useMinDetect = (int)argMinDetect;
-    useMinLength = ceil(argMinLength * kvideoRate);
-    useMaxSep    = rint(argMaxSep * kvideoRate + 0.5);
-    usePad       = rint(argPad * kvideoRate + 0.5);
-    updateMessage = "COMMFLAG_UPDATE " + QString(progid) + ' ';
-    printf("debug%cThreshold=%.1f, MinQuiet=%.2f, MinDetect=%.1f, MinLength=%.1f, MaxSep=%.1f,"
-           " Pad=%.2f\n", DELIMITER, argThreshold, argMinQuiet, argMinDetect,
-           argMinLength, argMaxSep, argPad);
-    printf("debug%cFrame rate is %.2f, Detecting silences below %d that last for at least %d frames\n",
-           DELIMITER, kvideoRate, useThreshold, useMinQuiet);
-    printf("debug%cClusters are composed of a minimum of %d silences closer than %d frames and must be\n",
-           DELIMITER, useMinDetect, useMaxSep);
-    printf("debug%clonger than %d frames in total. Cuts will be padded by %d frames\n",
-           DELIMITER, useMinLength, usePad);
-    printf("debug%c< preroll, > postroll, - advert, ? too few silences, # too short, = comm marked\n",
-           DELIMITER);
-    printf("info%c           Start - End    Start - End      Duration         Interval    Level/Cnt\n", DELIMITER);
-    printf("info%c          frame - frame (mmm:ss-mmm:ss) frame (mm:ss.s)  frame (mmm:ss)\n", DELIMITER);
-}
 void report(const char* err,
@@ Line 793: / Line 480: @@
              const frameNumber_t interval,
              const int power)
-// Logs silences/clusters/cuts in standard format
+// Logs silences/clusters/cuts in a standard format
 {
      frameCount_t duration = end - start + 1;
-     printf("%s%c%c %7s %6d-%6d (%3d:%02ld-%3d:%02ld), %4d (%2d:%04.1f), %5d (%3d:%02ld), [%7d]\n",
+     printf("%s%c %7s %6d-%6d (%3d:%02ld-%3d:%02ld), %4d (%2d:%04.1f), %5d (%3d:%02ld), [%7d]\n",
-            err, DELIMITER, type, msg1, start, end,
+            err, type, msg1, start, end,
-            (start+13) / krateInMins, lrint(start / kvideoRate) % 60,
+            (start+13) / Arg::krateInMins, lrint(start / Arg::kvideoRate) % 60,
-            (end+13) / krateInMins, lrint(end / kvideoRate) % 60,
+            (end+13) / Arg::krateInMins, lrint(end / Arg::kvideoRate) % 60,
-            duration, (duration+1) / krateInMins, fmod(duration / kvideoRate, 60),
+            duration, (duration+1) / Arg::krateInMins, fmod(duration / Arg::kvideoRate, 60),
-            interval, (interval+13) / krateInMins, lrint(interval / kvideoRate) % 60, power);
+            interval, (interval+13) / Arg::krateInMins, lrint(interval / Arg::kvideoRate) % 60, power);
 }
-void makeCut(frameNumber_t start, frameNumber_t end)
+void processSilence()
-// Logs cuts and sends player update message
+// Process a silence detection
 {
-     // log cut
+     // ignore detections that are too short
-     report("cut", '=', "Cut", start, end, 0, 0);
+     if (currentSilence->state == Silence::detection && currentSilence->length < Arg::useMinQuiet)
+    {
+        // throw it away
+        delete currentSilence;
+        currentSilence = NULL;
+    }
+    else
+    {
+        // record new silence
+        clist->addSilence(currentSilence);
-    // Update player
+        // assign it to a cluster
-    // add comma unless it's first cut
+        if (currentCluster)
-    if (!updateMessage.endsWith(' '))
+         {
-         updateMessage += ',';
+             // add to existing cluster
+            currentCluster->extend(currentSilence);
-    updateMessage += QString("%1:%2,%3:%4")
+        }
-            .arg(start).arg(MARK_COMM_START)
+        else if (currentSilence->interval <= Arg::useMaxSep) // only possible for very first silence
-             .arg(end).arg(MARK_COMM_END);
-    gCoreContext->SendMessage(updateMessage);
-//    printf("debug%c  Sending %s\n", DELIMITER, updateMessage.toAscii().constData());
-}
-void analyseSilence()
-// Determines if current silence belongs to existing cluster or starts a new one
-{
-    Silence* thisSilence;
-    Silence* prevSilence = clist->getLastSilence();
-    // record new detected silence
-    thisSilence = clist->addSilence(currentSilence);
-    // check for a cluster break
-    if (currentSilence.interval <= useMaxSep)
-    {
-        if (!prevSilence)
          {
              // First silence is close to prog start so extend cluster to the start
              // by inserting a fake silence at prog start and starting the cluster there
-             currentCluster.restart(clist->insertStartSilence());
+             currentCluster = new Cluster(clist->insertStartSilence());
+            currentCluster->extend(currentSilence);
          }
-         // add this silence to current cluster
+         else
-         currentCluster.extend(thisSilence);
+        {
+            // this silence is the start of a new cluster
+            currentCluster = new Cluster(currentSilence);
+         }
+        report(prefixdebug, currentSilence->state_log[currentSilence->state], "Silence",
+               currentSilence->start, currentSilence->end,
+               currentSilence->interval, currentSilence->power);
+        // silence is now owned by the list, start looking for next
+        currentSilence = NULL;
      }
-    else // start of new cluster
+}
-    {
-        // for first silence there is no previous cluster
+void processCluster()
-        if (prevSilence)
+// Process a completed cluster
-        {
+{
-            // complete previous cluster, which finished at previous silence
+    // record new cluster
-            currentCluster.end = prevSilence;
+    clist->addCluster(currentCluster);
-            Cluster* c = clist->addCluster(currentCluster);
+    report(prefixinfo, currentCluster->state_log[currentCluster->state], "Cluster",
+           currentCluster->start->start, currentCluster->end->end,
+           currentCluster->interval, currentCluster->silenceCount);
-            // log cluster
+    // only flag clusters at final state
-            report("info", c->state_log[c->state], "Cluster",
+    if (currentCluster->state > Cluster::unset)
-                   c->start->start, c->end->end, c->interval, c->silenceCount);
+        report(prefixcut, '=', "Cut", currentCluster->padStart, currentCluster->padEnd, 0, 0);
-            // create cut
+    // cluster is now owned by the list, start looking for next
-            switch (c->state)
+    currentCluster = NULL;
-            {
-            case Cluster::preroll:
-                makeCut(c->start->start, c->end->end - usePad);
-                break;
-            case Cluster::postroll:
-                makeCut(c->start->start + usePad, c->end->end);
-                break;
-            case Cluster::advert:
-                makeCut(c->start->start + usePad, c->end->end - usePad);
-                break;
-            default:;
-            }
-        }
-        // this silence is the start of a new cluster
-        if (thisSilence)
-            currentCluster.restart(thisSilence);
-    }
-    // log silence
-    report("debug", thisSilence->state_log[thisSilence->state], "Silence",
-           thisSilence->start, thisSilence->end,
-           thisSilence->interval, thisSilence->power);
 }
@@ Line 887: / Line 555: @@
 // Detect silences and allocate to clusters
 {
-     // Require Myth context for sending player update messages
+     // Remove logging prefixes if writing to terminal
-     QCoreApplication a(argc, argv);
+     if (isatty(1))
-    QCoreApplication::setApplicationName("silence");
+        prefixcut[0] = prefixinfo[0] = prefixdebug[0] = prefixerr[0] = '\0';
-     MythContext* gContext = new MythContext(MYTH_BINARY_VERSION);
+     // flush output buffer after every line
+    setvbuf(stdout, NULL, _IOLBF, 0);
-     if (!gContext->Init( false, /*use gui*/
+     Arg::parse(argc, argv);
-                         false, /*prompt for backend*/
-                         false, /*bypass auto discovery*/
-                         false)) /*ignoreDB*/
-    {
-        printf("err%cContext initialisation failed\n", DELIMITER);
-        exit(1);
-    }
-    gCoreContext->ConnectToMasterServer();
      /* Check the input is an audiofile. */
@@ Line 907: / Line 568: @@
      SNDFILE* input = sf_open_fd(STDIN_FILENO, SFM_READ, &metadata, SF_FALSE);
      if (NULL == input) {
-         sf_perror(NULL);
+         error("libsndfile error:", false);
-         return sf_error(NULL);
+         error(sf_strerror(NULL));
      }
-    parseArgs(argc, argv);
      /* Allocate data buffer to contain audio data from one video frame. */
-     const size_t frameSamples = metadata.channels * metadata.samplerate / kvideoRate;
+     const size_t frameSamples = metadata.channels * metadata.samplerate / Arg::kvideoRate;
      int* samples = (int*)malloc(frameSamples * sizeof(int));
-     if (NULL == samples) {
+     if (NULL == samples)
-         perror(NULL);
+         error("Couldn't allocate memory");
-        return errno;
-    }
-     // initialise silence/cluster list with relevant limits
+     // create silence/cluster list
-     clist = new ClusterList(useMinDetect, useMinLength);
+     clist = new ClusterList();
-     // flush output buffer after every line
+     // Kill head of pipeline if timeout happens.
-     setvbuf(stdout, NULL, _IOLBF, 0);
+     signal(SIGALRM, watchdog);
+    sigset_t intmask;
-     // start outside of a silence
+    sigemptyset(&intmask);
-     bool in_silence = false;
+    sigaddset(&intmask, SIGALRM);
+     sigprocmask(SIG_UNBLOCK, &intmask, NULL);
+     alarm(30);
      // Process the input one frame at a time and process cuts along the way.
@@ Line 935: / Line 594: @@
      while (frameSamples == static_cast<size_t>(sf_read_int(input, samples, frameSamples)))
      {
+        alarm(30);
          frames++;
          // determine average audio level in this frame
-         long avgabs = 0;
+         unsigned long long avgabs = 0;
          for (unsigned i = 0; i < frameSamples; i++)
              avgabs += abs(samples[i]);
@@ Line 944: / Line 604: @@
          // check for a silence
-         if (avgabs < useThreshold)
+         if (avgabs < Arg::useThreshold)
          {
-             if (in_silence)
+             if (currentSilence)
              {
                  // extend current silence
-                 currentSilence.extend(frames, avgabs);
+                 currentSilence->extend(frames, avgabs);
              }
              else // transition to silence
              {
-                in_silence = true;
+                 // start a new silence
+                 currentSilence = new Silence(frames, avgabs);
-                 // start of new silence
-                 currentSilence.restart(frames, avgabs);
              }
          }
-         else if (in_silence) // transition out of silence
+         else if (currentSilence) // transition out of silence
          {
-             in_silence = false;
+             processSilence();
+        }
-            // process completed silence if it's long enough
+        // in noise: check for cluster completion
-            if (currentSilence.length >= useMinQuiet)
+        else if (currentCluster && frames > currentCluster->completesAt)
+        {
-                analyseSilence();
+            processCluster();
          }
      }
+    // Complete any current silence (prog may have finished in silence)
-     // Ensure there's a silence at prog end so that any post-roll cluster extends right to the end.
+    if (currentSilence)
-     // If we're already in silence then use the existing start...
+    {
-     if (!in_silence)
+        processSilence();
+    }
+     // extend any cluster close to prog end
+    if (currentCluster && frames <= currentCluster->completesAt)
+    {
+        // generate a silence at prog end and extend cluster to it
+        currentSilence = new Silence(frames, 0, Silence::progEnd);
+        processSilence();
+    }
+     // Complete any final cluster
+     if (currentCluster)
      {
-         // ..otherwise generate a dummy silence at prog end
+         processCluster();
-        currentSilence.restart(frames, 0, Silence::progEnd);
      }
-    analyseSilence();
-    // Generate a dummy silence a long time after prog end to complete any unfinished cluster
-    currentSilence.restart(frames + useMaxSep + 2, 0, Silence::beyondEnd);
-    analyseSilence();
 }
 </pre>
 }}
+==== silence.py ====
 {{Code box|silence.py|
 <pre>
 #!/usr/bin/env python
 # Build a skiplist from silence in the audio track.
-# Roger Siddons v1.0
+# v1.0 Roger Siddons
+# v2.0 Fix progid for job/player messages
+# v3.0 Send player messages via Python
+# v3.1 Fix commflag status, pad preset. Improve style & make Python 3 compatible
+# v4.0 silence.cpp will kill the head of the pipeline (tail) when recording finished
+# v4.1 Use unicode for foreign chars
+# v4.2 Prevent BE writeStringList errors
+# v5.0 Improve exception handling/logging. Fix player messages (0.26+ only)
 import MythTV
 import os
@@ Line 999: / Line 670: @@
 import sys
-kExe_Catagrower = '/usr/local/bin/catagrower'
+kExe_Silence = '/usr/local/bin/silence'
-kExe_Mausc      = '/usr/local/bin/silence'
+kUpmix_Channels = '6' # Change this to 2 if you never have surround sound in your recordings.
-kUpmix_Channels = '1'
-kInput_Timeout  = '30'
-class MYLOG( MythTV.MythLog ):
+class MYLOG(MythTV.MythLog):
-    "A specialised logger"
+  "A specialised logger"
-    def __init__(self, db):
+  def __init__(self, db):
-        "Initialise logging"
+    "Initialise logging"
-        MythTV.MythLog.__init__(self, 'm', db)
+    MythTV.MythLog.__init__(self, '', db)
-    def log(self, msg, level=MythTV.MythLog.INFO):
+  def log(self, msg, level = MythTV.MythLog.INFO):
-        "Log message"
+    "Log message"
-        # prepend string to msg so that rsyslog routes it to correct logfile
+    # prepend string to msg so that rsyslog routes it to mythcommflag.log logfile
-        MythTV.MythLog.log(self, MythTV.MythLog.COMMFLAG, level, 'mythcommflag: ' + msg.rstrip('\n'))
+    MythTV.MythLog.log(self, MythTV.MythLog.COMMFLAG, level, 'mythcommflag: ' + msg.rstrip('\n'))
 class PRESET:
-    "Manages the presets (parameters passed to the detection algorithm)"
+  "Manages the presets (parameters passed to the detection algorithm)"
-    # define arg ordering and default values
+  # define arg ordering and default values
-    argname = ['thresh', 'minquiet', 'mindetect', 'minbreak', 'maxsep', 'pad']
+  argname = ['thresh', 'minquiet', 'mindetect', 'minbreak', 'maxsep', 'pad']
-    argval  = [  -75,       0.16,        6,          120,       120,    0.48]
+  argval  = [  -75,       0.16,        6,          120,       120,    0.48]
-    # dictionary holds value for each arg
+  # dictionary holds value for each arg
-    argdict = collections.OrderedDict(zip(argname, argval))
+  argdict = collections.OrderedDict(list(zip(argname, argval)))
-    def _validate(self, k, v):
+  def _validate(self, k, v):
-        "Converts arg input from string to float or None if invalid/not supplied"
+    "Converts arg input from string to float or None if invalid/not supplied"
-        if v is None or v == '':
+    if v is None or v == '':
-            return k, None
+      return k, None
-        try:
+    try:
-            return k, float(v)
+      return k, float(v)
-        except ValueError:
+    except ValueError:
-            self.logger.log('Preset ' + k + ' (' + str(v) + ') is invalid - will use default',
+      self.logger.log('Preset ' + k + ' (' + str(v) + ') is invalid - will use default',
-                MYLOG.ERR)
+        MYLOG.ERR)
-            return k, None
+      return k, None
-    def __init__(self, _logger):
+  def __init__(self, _logger):
-        "Initialise preset manager"
+    "Initialise preset manager"
-        self.logger = _logger
+    self.logger = _logger
-    def getFromArg(self, line):
+  def getFromArg(self, line):
-        "Parses preset values from command-line string"
+    "Parses preset values from command-line string"
-        self.logger.log('Parsing presets from "' + line + '"', MYLOG.DEBUG)
+    self.logger.log('Parsing presets from "' + line + '"', MYLOG.DEBUG)
-        if line: # ignore empty string
+    if line:  # ignore empty string
-            vals = [i.strip() for i in line.split(',')] # split individual params
+      vals = [i.strip() for i in line.split(',')]  # split individual params
-            # convert supplied values to float & match to appropriate arg name
+      # convert supplied values to float & match to appropriate arg name
-            validargs = map(self._validate, self.argname, vals)
+      validargs = list(map(self._validate, self.argname, vals[0:len(self.argname)]))
-            # remove missing/invalid values from list & replace default values with the rest
+      # remove missing/invalid values from list & replace default values with the rest
-            self.argdict.update(dict(filter(lambda (k,v): False if v is None else (k,v), validargs)))
+      self.argdict.update(v for v in validargs if v[1] is not None)
-    def getFromFile(self, filename, title, callsign):
+  def getFromFile(self, filename, title, callsign):
-        "Gets preset values from a file"
+    "Gets preset values from a file"
-        self.logger.log('Using preset file "' + filename + '"', MYLOG.DEBUG)
+    self.logger.log('Using preset file "' + filename + '"', MYLOG.DEBUG)
-        try:
+    try:
-            with open(filename) as presets:
+      with open(filename) as presets:
-                for rawline in presets:
+        for rawline in presets:
-                    line = rawline.strip()
+          line = rawline.strip()
-                    if line and (not line.startswith('#')): # ignore empty & comment lines
+          if line and (not line.startswith('#')):  # ignore empty & comment lines
-                        vals = [i.strip() for i in line.split(',')] # split individual params
+            vals = [i.strip() for i in line.split(',')]  # split individual params
-                        # match preset name to recording title or channel
+            # match preset name to recording title or channel
-                        pattern = re.compile(vals[0], re.IGNORECASE)
+            pattern = re.compile(vals[0], re.IGNORECASE)
-                        if pattern.match(title) or pattern.match(callsign):
+            if pattern.match(title) or pattern.match(callsign):
-                            self.logger.log('Using preset "' + line.strip() + '"')
+              self.logger.log('Using preset "' + line.strip() + '"')
-                            # convert supplied values to float & match to appropriate arg name
+              # convert supplied values to float & match to appropriate arg name
-                            validargs = map(self._validate, self.argname, vals[1:min(len(vals),len(self.argname))])
+              validargs = list(map(self._validate, self.argname,
-                            # remove missing/invalid values from list & replace default values with the rest
+                         vals[1:1 + len(self.argname)]))
-                            self.argdict.update(dict(filter(lambda (k,v): False if v is None else (k,v), validargs)))
+              # remove missing/invalid values from list &
-                            break
+              # replace default values with the rest
-                else:
+              self.argdict.update(v for v in validargs if v[1] is not None)
-                    self.logger.log('No preset found for "' + title + '" or "' + callsign + '"')
+              break
-        except IOError:
+        else:
-            self.logger.log('Presets file "' + filename + '" not found', MYLOG.ERR)
+          self.logger.log('No preset found for "' + title.encode('utf-8') + '" or "' + callsign.encode('utf-8') + '"')
-        return self.argdict
+    except IOError:
+      self.logger.log('Presets file "' + filename + '" not found', MYLOG.ERR)
+    return self.argdict
+  def getValues(self):
+    "Returns params as a list of strings"
+    return [str(i) for i in list(self.argdict.values())]
-    def getValues(self):
-        "Returns params as a list of strings"
-        return [str(i) for i in self.argdict.values()]
 def main():
-    "Commflag a recording"
+  "Commflag a recording"
+  try:
      # define options
      parser = argparse.ArgumentParser(description='Commflagger')
-     parser.add_argument('--preset',
+     parser.add_argument('--preset', help='Specify values as "Threshold, MinQuiet, MinDetect, MinLength, MaxSep, Pad"')
-        help='Specify values as "Threshold, MinQuiet, MinDetect, MinLength, MaxSep, Pad"')
      parser.add_argument('--presetfile', help='Specify file containing preset values')
-     parser.add_argument('--chanid', help='Use chanid for manual operation')
+     parser.add_argument('--chanid', type=int, help='Use chanid for manual operation')
      parser.add_argument('--starttime', help='Use starttime for manual operation')
+    parser.add_argument('--dump', action="store_true", help='Generate stack trace of exception')
      parser.add_argument('jobid', nargs='?', help='Myth job id')
@@ Line 1,097: / Line 769: @@
      args = parser.parse_args()
+    # connect to backend
      db = MythTV.MythDB()
      logger = MYLOG(db)
+    be = MythTV.BECache(db=db)
+    logger.log('')	# separate jobs in logfile
      if args.jobid:
-        job = MythTV.Job(args.jobid, db)
+      logger.log('Starting job %s'%args.jobid, MYLOG.INFO)
-        chanid = job.chanid
+      job = MythTV.Job(args.jobid, db)
-        starttime = job.starttime
+      chanid = job.chanid
-        timeout = kInput_Timeout
+      starttime = job.starttime
      elif args.chanid and args.starttime:
-        job = None
+      job = None
-        chanid = args.chanid
+      chanid = args.chanid
-         starttime = args.starttime
+      try:
-         timeout = '1'
+        # only 0.26+
+         starttime = MythTV.datetime.duck(args.starttime)
+      except AttributeError:
+         starttime = args.starttimeaction="store_true"
      else:
-        logger.log('Both chanid and starttime must be specified', MYLOG.ERR)
+      logger.log('Both --chanid and -starttime must be specified', MYLOG.ERR)
-        sys.exit(1)
+      sys.exit(1)
-     # get recording
+     # mythplayer update message uses a 'chanid_utcTimeAsISODate' format to identify recording
      try:
-        rec = MythTV.Recorded((chanid, starttime), db)
+      # only 0.26+
-     except:
+      utc = starttime.asnaiveutc()
-        if job:
+     except AttributeError:
-            job.update({'status':job.ERRORED, 'comment':'ERROR: Could not find recording.'})
+      utc = starttime
-        logger.log('Could not find recording', MYLOG.ERR)
-        sys.exit(1)
+    progId = '%d_%s'%(chanid, str(utc).replace(' ', 'T'))
+    # get recording
+    logger.log('Seeking chanid %s, starttime %s' %(chanid, starttime), MYLOG.INFO)
+    rec = MythTV.Recorded((chanid, starttime), db)
      channel = MythTV.Channel(chanid, db)
-    logger.log('')
+     logger.log('Processing: ' + channel.callsign.encode('utf-8') + ', ' + str(rec.starttime)
-     logger.log('Processing: ' + str(channel.callsign) + ', ' + str(rec.starttime)
+      + ', "' + rec.title.encode('utf-8') + ' - ' + rec.subtitle.encode('utf-8')+ '"')
-        + ', "' + str(rec.title) + ' - ' + str(rec.subtitle) + '"')
-    if rec.commflagged == 3:
-        commfree = 1
-        logger.log('--- Comm-free programme - will detect pre-roll & post-roll adverts only')
-    else:
-        commfree = 0
      sg = MythTV.findfile(rec.basename, rec.storagegroup, db)
      if sg is None:
-        if job:
+      logger.log("Can't access file %s from %s"%(rec.basename, rec.storagegroup), MYLOG.ERR)
-            job.update({'status':job.ERRORED, 'comment':'ERROR: Local access to recording not found.'});
+      try:
-        logger.log('Local access to recording not found', MYLOG.ERR)
+        job.update({'status': job.ERRORED, 'comment': "Couldn't access file"})
-        sys.exit(1)
+      except AttributeError : pass
+      sys.exit(1)
-    # player update message needs prog id
-    progId = str(chanid) + '_' + str(starttime)
      # create params with default values
      param = PRESET(logger)
+    # read any supplied presets
      if args.preset:
-        param.getFromArg(args.preset)
+      param.getFromArg(args.preset)
-     elif args.presetfile: # use preset file
+     elif args.presetfile:  # use preset file
-        param.getFromFile(args.presetfile, rec.title, channel.callsign)
+      param.getFromFile(args.presetfile, rec.title, channel.callsign)
+    # Pipe file through ffmpeg to extract uncompressed audio stream. Keep going till recording is finished.
      infile = os.path.join(sg.dirname, rec.basename)
+    p1 = subprocess.Popen(["tail", "--follow", "--bytes=+1", infile], stdout=subprocess.PIPE)
+    p2 = subprocess.Popen(["mythffmpeg", "-loglevel", "quiet", "-i", "pipe:0",
+                "-f", "au", "-ac", kUpmix_Channels, "-"],
+                stdin=p1.stdout, stdout=subprocess.PIPE)
+    # Pipe audio stream to C++ silence which will spit out formatted log lines
+    p3 = subprocess.Popen([kExe_Silence, "%d" % p1.pid] + param.getValues(), stdin=p2.stdout,
+                stdout=subprocess.PIPE)
      # Purge any existing skip list and flag as in-progress
+    rec.commflagged = 2
      rec.markup.clean()
-    rec.commflagged = 2
      rec.update()
-     # Write out the file contents and keep going till recording is finished.
+     # Process log output from C++ silence
-    p1 = subprocess.Popen([kExe_Catagrower, infile, timeout], stdout = subprocess.PIPE)
-    # Pipe through avconv to extract uncompressed audio stream.
-    p2 = subprocess.Popen(["mythffmpeg", "-loglevel", "quiet", "-i", "pipe:0",
-             "-ar", "8000", "-f", "au", "-ac", kUpmix_Channels, "-"],
-            stdin = p1.stdout, stdout = subprocess.PIPE)
-    # Pipe to mausc which will spit out a list of breaks.
-    p3 = subprocess.Popen([kExe_Mausc] + param.getValues() + [str(commfree)] + [progId],
-    stdin = p2.stdout, stdout = subprocess.PIPE)
-    # Store breaks in the database.
      breaks = 0
-     level = {'info':MYLOG.INFO, 'debug':MYLOG.DEBUG, 'err':MYLOG.ERR}
+     level = {'info': MYLOG.INFO, 'debug': MYLOG.DEBUG, 'err': MYLOG.ERR}
      while True:
-        line = p3.stdout.readline()
+      line = p3.stdout.readline()
-        if line:
+      if line:
-            flag, info = line.split('@', 1)
+        flag, info = line.split('@', 1)
-            if flag == 'cut':
+        if flag == 'cut':
-                # extract numbers from log
+          # extract numbers from log line
-                numbers = re.findall('\d+', info)
+          numbers = re.findall('\d+', info)
-                # mark advert in recording
+          logger.log(info)
-                rec.markup.append(numbers[0], rec.markup.MARK_COMM_START, None)
+          # mark advert in database
-                rec.markup.append(numbers[1], rec.markup.MARK_COMM_END, None)
+          rec.markup.append(int(numbers[0]), rec.markup.MARK_COMM_START, None)
-                rec.update()
+          rec.markup.append(int(numbers[1]), rec.markup.MARK_COMM_END, None)
-                breaks += 1
+          rec.update()
-                logger.log(info)
+          breaks += 1
-            else:
+          # send new advert skiplist to MythPlayers
-                # use warning for unexpected log levels
+          skiplist = ['%d:%d,%d:%d'%(x, rec.markup.MARK_COMM_START, y, rec.markup.MARK_COMM_END)
-                logger.log(info, level.get(flag, MYLOG.WARNING))
+                   for x, y in rec.markup.getskiplist()]
-        else:
+          mesg = 'COMMFLAG_UPDATE %s %s'%(progId, ','.join(skiplist))
-           break
+#         logger.log('  Sending %s'%mesg,  MYLOG.DEBUG)
+          result = be.backendCommand("MESSAGE[]:[]" + mesg)
-    if job:
+          if result != 'OK':
-        job.update({'status':272,
+            logger.log('Sending update message to backend failed, response = %s, message = %s'% (result, mesg), MYLOG.ERR)
-                    'comment':'Audio commflag detected %s breaks.' % breaks});
+        elif flag in level:
-    logger.log('Audio commflag detected %s breaks.' % breaks)
+          logger.log(info, level.get(flag))
+        else:  # unexpected prefix
+          # use warning for unexpected log levels
+          logger.log(flag, MYLOG.WARNING)
+      else:
+        break
      # Signal comflagging has finished
-     if commfree:
+     rec.commflagged = 1
-        rec.commflagged = 3
-    else:
-        rec.commflagged = 1
      rec.update()
+    logger.log('Detected %s adverts.' % breaks)
+    try:
+      job.update({'status': 272, 'comment': 'Detected %s adverts.' % breaks})
+    except AttributeError : pass
+    # Finishing too quickly can cause writeStringList/socket errors in the BE. (pre-0.28 only?)
+    # A short delay prevents this
+    import time
+    time.sleep(1)
+  except Exception as e:
+    # get exception before we generate another
+    import traceback
+    exc_type, exc_value, frame = sys.exc_info()
+    # get stacktrace as a list
+    stack = traceback.format_exception(exc_type, exc_value, frame)
+    # set status
+    status = 'Failed due to: "%s"'%e
+    try:
+      logger.log(status, MYLOG.ERR)
+    except : pass
+    try:
+      job.update({'status': job.ERRORED, 'comment': 'Failed.'})
+    except : pass
+    # populate stack trace with vars
+    try:
+      if args.dump:
+        # insert the frame local vars after each frame trace
+        # i is the line index following the frame trace; 0 is the trace mesg, 1 is the first code line
+        i = 2
+        while frame is not None:
+          # format local vars
+          vars = []
+          for name, var in frame.tb_frame.f_locals.iteritems():
+            try:
+              text = '%s' % var
+              # truncate vars that are too long
+              if len(text) > 1000:
+                text = text[:1000] + '...'
+            except Exception as e: # some var defs may be incomplete
+              text = '<Unknown due to: %s>'%e
+            vars.append('@ %s = %s'%(name, text))
+          # insert local stack contents after code trace line
+          stack.insert(i, '\n'.join(['@-------------'] + vars + ['@-------------\n']))
+          # advance over our insertion & the next code trace line
+          i += 2
+          frame = frame.tb_next
+        logger.log('\n'.join(stack), MYLOG.ERR)
+    except : pass
+    sys.exit(1)
 if __name__ == '__main__':
-    main()
+  main()
 </pre>
 }}
+==== Makefile ====
 {{Code box|Makefile|
 <pre>
-CC=g++
+CC        = g++
-CFLAGS=-c -Wall -std=c++0x
+CFLAGS    = -c -Wall -std=c++0x
-LDFLAGS=
+LIBPATH   = -L/usr/lib
-INCPATH = -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtNetwork -I/usr/include/qt4/QtSql -I/usr/include/qt4 -I/usr/include/mythtv
+TARGETDIR = /usr/local/bin
-LIBPATH = -L/usr/lib -L/usr/lib/i386-linux-gnu
-LIBS = -lsndfile -lQtCore -lmythbase-0.26 -lmyth-0.26
+.PHONY: clean install
-PREFIX = /usr/local/bin
-all: silence.cpp catagrower.cpp silence catagrower
+all: silence
-catagrower: catagrower.o
-	$(CC) $(LDFLAGS) catagrower.o -o $(PREFIX)/$@
 silence: silence.o
-	$(CC) $(LDFLAGS) silence.o -o $(PREFIX)/$@ $(LIBPATH) $(LIBS)
+	$(CC) silence.o -o $@ $(LIBPATH) -lsndfile
 .cpp.o:
-	$(CC) $(CFLAGS) $(INCPATH) $< -o $@
+	$(CC) $(CFLAGS) $< -o $@
+install: silence silence.py
+	install -p -t $(TARGETDIR) $^
 clean:
-	rm -f $(PREFIX)/silence $(PREFIX)/catagrower *.o
+	-rm -f silence *.o
 </pre>
 }}