Difference between revisions of "Commercial detection with silences"

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m (Algorithm)
(Updated cluster version to v2)
Line 322: Line 322:
 
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.
 
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.
 
*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.
 
*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 329:
  
 
=== Algorithm ===
 
=== 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.
 
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.
Line 335: Line 335:
 
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.
 
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 ===
+
=== Change Summary ===
 
*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.
 
*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.
+
*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/ though.
+
*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/
*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.  
+
 
 +
=== MythPlayer Interaction ===
 +
Commercial markups are stored in the Myth database. The script writes to the database (via the Python bindings) as commercials are detected. However MythPlayer only reads them from the database once, when playback starts. Thus it will not be aware of any commercials that have been detected after playback started. This situation occurs mainly when watching programmes whilst they are still recording.
 +
 
 +
MythPlayer is capable of being notified of newly flagged commercials via messages. However to do this, the script needs to be built with Myth & Qt header files, which are not usually installed on packaged Myth installations such as MythBuntu. It is possible to install the requisite headers on such systems. However I am not familiar enough with them to comment on the wisdom of doing so. I believe it is safe but be aware that the packages also contain libraries - updates could break Myth if they are not synchronised correctly.
 +
 
 +
If you do not install the headers and watch in-progress recordings (whilst they are being flagged), then periodically quitting playback and re-starting it will refresh the commercial markups.
 +
 
 +
As presented, the script does not need the headers and will build on packaged systems. If you have installed the headers then uncomment the first line of silence.cpp so that USE_HEADERS is defined. This will enable the messaging functionality.
 +
 
 +
Currently adverts are flagged <maxsep> after they finishes. An experimental feature enables flagging <mindetect> after an advert starts, which may be useful when watching close to real-time. However, it is currently ineffective because MythPlayer prohibits comm-skipping close to programme end.
 +
 
 +
Ideally MythPlayer notification should be done via Python - I'm investigating this.
 +
 
 +
=== Requirements ===
 +
*Compilation environment (gcc, make) - install package build-essential
 +
*[http://www.mega-nerd.com/libsndfile/ libsndfile] for reading audio samples - install package libsndfile-dev
 +
*Optionally, Myth & Qt header files in /usr/include for communicating with MythPlayer. See [[#MythPlayer Interaction]]. These are not usually installed by packaged versions of Myth, ie. Mythbuntu, but can be found in packages libmyth-dev and libqt4-dev.
 +
 
 +
=== Building ===
 +
*Copy catagrower.cpp, silence.cpp, silence.py & Makefile to a new directory and cd there.
 +
*Modify silence.cpp if you have headers installed. See [[#MythPlayer Interaction]]
 +
*Build the silence & catagrower executables 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.
 +
*If using the headers, theoretically you should rebuild after every Myth update. However, the headers used rarely change so the script will probably continue to run.
  
 
=== Notes ===
 
=== 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 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.
 
*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.
*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'.
 
*<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.
 
*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.
 
*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.
 
*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 ===
 
=== 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% %VERBOSELEVEL% --loglevel debug
 
You can also run it manually from the command line like this:
 
You can also run it manually from the command line like this:
 
   silence.py --chanid 1004 --starttime 20130117220000 --loglevel debug
 
   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 ===
 
=== Channel Presets ===
Line 365: Line 394:
 
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:
 
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% %VERBOSELEVEL% --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"
  
 
This is my preset file which customises the processing of 4 regular programmes and 'tunes' some channels.
 
This is my preset file which customises the processing of 4 regular programmes and 'tunes' some channels.
Line 398: Line 430:
 
}}
 
}}
  
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;
+
=== TroubleShooting ===
  silence.py --chanid 1004 --starttime 20130117220000 --loglevel debug --preset "-80,,3,,180"
+
*If you get "Local access to recording not found" 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.
 +
*If you're using headers and the script stops working after updating Myth, then ensure the headers are up-to-date and rebuild.
  
 
{{Code box|catagrower.cpp|
 
{{Code box|catagrower.cpp|
Line 405: Line 439:
 
/* Copyright 2012 Crackers Phipps. */
 
/* Copyright 2012 Crackers Phipps. */
 
/* Public domain. */
 
/* Public domain. */
/* Compile with
 
  gcc -std=c99 -O catagrower.c -o catagrower
 
*/
 
  
 
/* MythTV files are often large. */
 
/* MythTV files are often large. */
Line 466: Line 497:
 
// Based on mausc.c by Tinsel Phipps.
 
// Based on mausc.c by Tinsel Phipps.
 
// v1.0 Roger Siddons
 
// v1.0 Roger Siddons
 +
// v2.0 Roger Siddons: Flag clusters asap, fix segfaults, optional headers
 
// Public domain. Requires libsndfile, libQtCore, libmythbase-0.x, libmyth-0.x
 
// Public domain. Requires libsndfile, libQtCore, libmythbase-0.x, libmyth-0.x
 
// Detects commercial breaks using clusters of audio silences
 
// Detects commercial breaks using clusters of audio silences
  
 +
// Uncomment this if you have header files for Myth & Qt installed in /usr/include
 +
// It enables MythPlayer update messages (for watching a programme whilst it is commflagging)
 +
//#define USE_HEADERS 1
 +
 +
// Experimental: Only effective with a modified MythPlayer that allows comm-skipping close to prog end.
 +
// If true, MythPlayer is notified as soon as an advert starts, then again as the advert grows in size.
 +
// If false, MythPlayer will only be notified once per advert, shortly after the advert has finished
 +
const bool kUseAggressiveFlagging = false;
 +
 +
#include <cstdlib>
 +
#include <cmath>
 +
#include <cerrno>
 +
#include <climits>
 +
#include <deque>
 
#include <sndfile.h>
 
#include <sndfile.h>
 
#include <unistd.h>
 
#include <unistd.h>
 +
 +
#ifdef USE_HEADERS
 
#include <mythcorecontext.h>
 
#include <mythcorecontext.h>
 
#include <mythcontext.h>
 
#include <mythcontext.h>
Line 476: Line 524:
 
#include <programtypes.h>
 
#include <programtypes.h>
 
#include <QCoreApplication>
 
#include <QCoreApplication>
 +
#endif
  
 
#define DELIMITER '@' // must correlate with python wrapper
 
#define DELIMITER '@' // must correlate with python wrapper
Line 482: Line 531:
 
typedef unsigned frameCount_t;
 
typedef unsigned frameCount_t;
  
class Silence
+
void error(const char* mesg, bool die = true) {
// A detected silence
+
    printf("err%c%s\n", DELIMITER, mesg);
 +
    if (die)
 +
        exit(1);
 +
}
 +
 
 +
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
 +
int 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
 +
int commfree;                  // bool: true if prog originates from a comm-free channel
 +
char progId[40];                // programme ident: should be no bigger than "cccc_yyyy-mm-ddThh:mm:ss+hh:mm"
 +
 
 +
void usage()
 +
{
 +
    error("Usage: silence <threshold> <minquiet> <mindetect> <minlength> <maxsep> <pad> <commfree> <progid>", 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("<commfree> : (int)    1 if prog is comm-free, 0 otherwise.", false);
 +
    error("<progid>  : (string) chan_starttime of program (for player updates).", false);
 +
    error("An AU format file should be fed into this program.", false);
 +
    error("Example: silence -75 0.1 5 60 90 0 1004_20121003090000 < audio.au");
 +
}
 +
 
 +
void parse(int argc, char **argv)
 +
// Parse args and convert to useable values (frames)
 +
{
 +
    if (9 != 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], "%f", &argThreshold))
 +
        error("Could not parse threshold option into a number");
 +
    if (1 != sscanf(argv[2], "%f", &argMinQuiet))
 +
        error("Could not parse minquiet option into a number");
 +
    if (1 != sscanf(argv[3], "%f", &argMinDetect))
 +
        error("Could not parse mindetect option into a number");
 +
    if (1 != sscanf(argv[4], "%f", &argMinLength))
 +
        error("Could not parse minlength option into a number");
 +
    if (1 != sscanf(argv[5], "%f", &argMaxSep))
 +
        error("Could not parse maxsep option into a number");
 +
    if (1 != sscanf(argv[6], "%f", &argPad))
 +
        error("Could not parse pad option into a number");
 +
    if (1 != sscanf(argv[7], "%d", &commfree))
 +
        error("Could not parse commfree option into a number");
 +
    if (1 != sscanf(argv[8], "%s", progId))
 +
        error("Could not parse progid option into a string");
 +
 
 +
    /* 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("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 flagged\n",
 +
          DELIMITER);
 +
    printf("info%c          Start - End    Start - End      Duration        Interval    Level/Count\n", DELIMITER);
 +
    printf("info%c          frame - frame (mmm:ss-mmm:ss) frame (mm:ss.s)  frame (mmm:ss)\n", DELIMITER);
 +
}
 +
}
 +
 
 +
namespace Comms
 +
// Manages MythPlayer communications
 +
{
 +
#ifdef USE_HEADERS
 +
QString updateMessage = "COMMFLAG_UPDATE "; // Player update message
 +
#endif
 +
 
 +
void initialise(int argc, char **argv)
 
{
 
{
public:
+
#ifdef USE_HEADERS
     enum state_t {detected, progStart, progEnd, beyondEnd};
+
    // Require Myth context for sending player update messages
    static const char state_log[5];
+
    QCoreApplication q(argc, argv);
 +
    QCoreApplication::setApplicationName("silence");
 +
 
 +
    MythContext* gContext = new MythContext(MYTH_BINARY_VERSION);
 +
 
 +
     if (!gContext->Init( false, /*use gui*/
 +
                        false, /*prompt for backend*/
 +
                        false, /*bypass auto discovery*/
 +
                        false)) /*ignoreDB*/
 +
        error("Myth Context initialisation failed");
  
     frameNumber_t start;   // frame of start
+
     gCoreContext->ConnectToMasterServer();
    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) {}
+
     // construct player update message
 +
    updateMessage += QString(Arg::progId) + ' ';
 +
#endif
 +
}
  
    Silence(frameNumber_t _start,
+
void send(frameNumber_t start, frameNumber_t end, bool completed = false)
            frameNumber_t _end,
+
// Sends list of all commbreaks defined so far
            state_t _state) : start(_start), end(_end), length(_end - _start + 1),
+
{
        interval(0), power(0), state(_state) {}
+
#ifdef USE_HEADERS
 +
    // requires comma seperator unless it's first advert
 +
    QString sep = (updateMessage.endsWith(' ') ? "" : ",");
 +
    // build new advert markups
 +
    QString newBreak = QString("%1%2:%3,%4:%5").arg(sep).arg(start).arg(MARK_COMM_START)
 +
            .arg(end).arg(MARK_COMM_END);
  
     void restart(frameNumber_t frame, double _power, state_t _state = detected)
+
     if (!completed || (completed && !kUseAggressiveFlagging)) {
    // Define start of a silence
+
        // send completed breaks followed by the one being built
    {
+
         gCoreContext->SendMessage(updateMessage + newBreak);
         start = end = frame;
+
         printf("debug%c  Sent %s\n", DELIMITER, (updateMessage + newBreak).toAscii().constData());
         length = 1;
 
        interval = 0;
 
        power = _power;
 
        state = _state;
 
 
     }
 
     }
 +
    if (completed)
 +
        // append completed break to message
 +
        updateMessage += newBreak;
 +
#endif
 +
}
 +
}
 +
 +
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)
 
     void extend(frameNumber_t frame, double _power)
     // Define end of a silence
+
     // Define end of the silence
 
     {
 
     {
 
         end = frame;
 
         end = frame;
         length = frame - start + 1;
+
         length = frame -threshold)) {
         // maintain running average power, allowing for missing frames
+
    fprintf(stderr, "Could not parse threshold option into a number.\n");
        // = (oldpower * (newlength - 1) + newpower)/ newlength
+
    usage(argv[0]);
        // a missing frame is assigned a power of the current average
+
    exit(2);
 +
  }
 +
  if (1 != sscanf(argv[2], "%f",  start + 1;
 +
         // maintain running average power: = (oldpower * (newlength - 1) + newpower)/ newlength
 
         power += (_power - power)/length;
 
         power += (_power - power)/length;
 
     }
 
     }
 
};
 
};
 
// c++0x doesn't allow initialisation within class
 
// c++0x doesn't allow initialisation within class
const char Silence::state_log[5] = {' ', '<', '>', 'v'};
+
const char Silence::state_log[3] = {'<', ' ', '>'};
  
 
class Cluster
 
class Cluster
 
// A cluster of silences
 
// 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:
 
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];
 
     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
 
     Silence* end;          // last silence
 +
    frameNumber_t padStart, padEnd; // padded cluster start/end frames
 
     unsigned silenceCount;  // number of silences
 
     unsigned silenceCount;  // number of silences
 
     frameCount_t length;    // number of frames
 
     frameCount_t length;    // number of frames
 
     frameCount_t interval;  // frames between end of last cluster and start of this one
 
     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 557: Line 754:
 
         end = _end;
 
         end = _end;
 
         silenceCount++;
 
         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
 
// 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
 
class ClusterList
Line 567: Line 769:
 
{
 
{
 
protected:
 
protected:
    const unsigned useMinDetect;
 
    const frameCount_t useMinLength;
 
 
 
     // list of detected silences
 
     // 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:
 
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()
 
     Silence* insertStartSilence()
 
     // Inserts a fake silence at the front of the silence list
 
     // Inserts a fake silence at the front of the silence list
 
     {
 
     {
 
         // create a single frame silence at frame 1 and insert it at front
 
         // 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);
 
         silence.push_front(ref);
 
         return 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
 
     // 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
+
ClusterList* clist; // List of completed silences & clusters
ClusterList* clist;
 
 
 
// 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. */
+
Silence* currentSilence; // the silence currently being detected/built
    useMinQuiet  = ceil(argMinQuiet * kvideoRate);
+
Cluster* currentCluster; // the cluster currently being built
    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,
 
void report(const char* err,
Line 794: Line 818:
 
             const frameNumber_t interval,
 
             const frameNumber_t interval,
 
             const int power)
 
             const int power)
// Logs silences/clusters/cuts in standard format
+
// Logs silences/clusters/cuts in a standard format
 
{
 
{
 
     frameCount_t duration = end - start + 1;
 
     frameCount_t duration = end - start + 1;
Line 800: Line 824:
 
     printf("%s%c%c %7s %6d-%6d (%3d:%02ld-%3d:%02ld), %4d (%2d:%04.1f), %5d (%3d:%02ld), [%7d]\n",
 
     printf("%s%c%c %7s %6d-%6d (%3d:%02ld-%3d:%02ld), %4d (%2d:%04.1f), %5d (%3d:%02ld), [%7d]\n",
 
           err, DELIMITER, type, msg1, start, end,
 
           err, DELIMITER, 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
 
             // 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
 
             // 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);
 
    }
 
    else // start of new cluster
 
    {
 
        // for first silence there is no previous cluster
 
        if (prevSilence)
 
 
         {
 
         {
             // complete previous cluster, which finished at previous silence
+
             // this silence is the start of a new cluster
             currentCluster.end = prevSilence;
+
             currentCluster = new Cluster(currentSilence);
 
+
        }
            Cluster* c = clist->addCluster(currentCluster);
+
        report("debug", currentSilence->state_log[currentSilence->state], "Silence",
 +
              currentSilence->start, currentSilence->end,
 +
              currentSilence->interval, currentSilence->power);
  
            // log cluster
+
        // flag player asap for clusters at final state
            report("info", c->state_log[c->state], "Cluster",
+
        if (kUseAggressiveFlagging && currentCluster->state > Cluster::unset)
                  c->start->start, c->end->end, c->interval, c->silenceCount);
+
            Comms::send(currentCluster->padStart, currentCluster->padEnd);
  
            // create cut
+
         // silence is now owned by the list, start looking for next
            switch (c->state)
+
         currentSilence = 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);
 
 
}
 
}
  
int main(int argc, char **argv)
+
void processCluster()
// Detect silences and allocate to clusters
+
// Process a completed cluster
 
{
 
{
     // Require Myth context for sending player update messages
+
     // record new cluster
     QCoreApplication a(argc, argv);
+
     clist->addCluster(currentCluster);
    QCoreApplication::setApplicationName("silence");
 
  
     MythContext* gContext = new MythContext(MYTH_BINARY_VERSION);
+
     report("info", currentCluster->state_log[currentCluster->state], "Cluster",
 +
          currentCluster->start->start, currentCluster->end->end,
 +
          currentCluster->interval, currentCluster->silenceCount);
  
     if (!gContext->Init( false, /*use gui*/
+
    // only interested in clusters at final state
                        false, /*prompt for backend*/
+
     if (currentCluster->state > Cluster::unset)
                        false, /*bypass auto discovery*/
 
                        false)) /*ignoreDB*/
 
 
     {
 
     {
         printf("err%cContext initialisation failed\n", DELIMITER);
+
         // flag player with completed cluster
         exit(1);
+
        Comms::send(currentCluster->padStart, currentCluster->padEnd, true);
 +
         // log cut
 +
        report("cut", '=', "Cut", currentCluster->padStart, currentCluster->padEnd, 0, 0);
 
     }
 
     }
     gCoreContext->ConnectToMasterServer();
+
     // 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
 +
{
 
     /* Check the input is an audiofile. */
 
     /* Check the input is an audiofile. */
 
     SF_INFO metadata;
 
     SF_INFO metadata;
Line 912: Line 909:
 
     }
 
     }
  
     parseArgs(argc, argv);
+
     Arg::parse(argc, argv);
 +
 
 +
    Comms::initialise(argc, argv);
  
 
     /* Allocate data buffer to contain audio data from one video frame. */
 
     /* 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));
 
     int* samples = (int*)malloc(frameSamples * sizeof(int));
Line 923: Line 922:
 
     }
 
     }
  
     // 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
 
     // flush output buffer after every line
 
     setvbuf(stdout, NULL, _IOLBF, 0);
 
     setvbuf(stdout, NULL, _IOLBF, 0);
 
    // start outside of a silence
 
    bool in_silence = false;
 
  
 
     // Process the input one frame at a time and process cuts along the way.
 
     // Process the input one frame at a time and process cuts along the way.
Line 945: Line 941:
  
 
         // check for a silence
 
         // check for a silence
         if (avgabs < useThreshold)
+
         if (avgabs < Arg::useThreshold)
 
         {
 
         {
             if (in_silence)
+
             if (currentSilence)
 
             {
 
             {
 
                 // extend current silence
 
                 // extend current silence
                 currentSilence.extend(frames, avgabs);
+
                 currentSilence->extend(frames, avgabs);
 
             }
 
             }
 
             else // transition to silence
 
             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
 +
        {
 +
            processSilence();
 +
        }
 +
        // in noise: check for cluster completion
 +
        else if (currentCluster && frames > currentCluster->completesAt)
 
         {
 
         {
             in_silence = false;
+
             processCluster();
 
 
            // process completed silence if it's long enough
 
            if (currentSilence.length >= useMinQuiet)
 
 
 
                analyseSilence();
 
 
         }
 
         }
 
     }
 
     }
 
+
    // Complete any current silence (if prog 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>
 
</pre>
Line 992: Line 990:
 
# Build a skiplist from silence in the audio track.
 
# Build a skiplist from silence in the audio track.
 
# Roger Siddons v1.0
 
# Roger Siddons v1.0
 +
# Roger Siddons v2.0 Fix progid for job/player messages
 +
 
import MythTV
 
import MythTV
 
import os
 
import os
Line 1,001: Line 1,001:
  
 
kExe_Catagrower = '/usr/local/bin/catagrower'
 
kExe_Catagrower = '/usr/local/bin/catagrower'
kExe_Mausc      = '/usr/local/bin/silence'
+
kExe_Silence    = '/usr/local/bin/silence'
 
kUpmix_Channels = '1'
 
kUpmix_Channels = '1'
kInput_Timeout  = '30'
+
kInput_Timeout  = '60'
  
 
class MYLOG( MythTV.MythLog ):
 
class MYLOG( MythTV.MythLog ):
Line 1,130: Line 1,130:
 
         + ', "' + str(rec.title) + ' - ' + str(rec.subtitle) + '"')
 
         + ', "' + str(rec.title) + ' - ' + str(rec.subtitle) + '"')
  
     if rec.commflagged == 3:
+
     commfree = 1 if rec.commflagged == 3 else 0
        commfree = 1
+
    if commfree:
 
         logger.log('--- Comm-free programme - will detect pre-roll & post-roll adverts only')
 
         logger.log('--- Comm-free programme - will detect pre-roll & post-roll adverts only')
    else:
 
        commfree = 0
 
  
 
     sg = MythTV.findfile(rec.basename, rec.storagegroup, db)
 
     sg = MythTV.findfile(rec.basename, rec.storagegroup, db)
Line 1,143: Line 1,141:
 
         sys.exit(1)
 
         sys.exit(1)
  
     # player update message needs prog id
+
     # player update message needs prog id (with time in Qt::ISODate format)
     progId = str(chanid) + '_' + str(starttime)
+
     progId = str(chanid) + '_' + str(starttime).replace(' ','T')
   
+
 
 
     # create params with default values
 
     # create params with default values
 
     param = PRESET(logger)
 
     param = PRESET(logger)
 
+
    # read any supplied presets
 
     if args.preset:
 
     if args.preset:
 
         param.getFromArg(args.preset)
 
         param.getFromArg(args.preset)
Line 1,163: Line 1,161:
 
     # Write out the file contents and keep going till recording is finished.
 
     # Write out the file contents and keep going till recording is finished.
 
     p1 = subprocess.Popen([kExe_Catagrower, infile, timeout], stdout = subprocess.PIPE)
 
     p1 = subprocess.Popen([kExe_Catagrower, infile, timeout], stdout = subprocess.PIPE)
     # Pipe through avconv to extract uncompressed audio stream.
+
     # Pipe through ffmpeg to extract uncompressed audio stream.
 
     p2 = subprocess.Popen(["mythffmpeg", "-loglevel", "quiet", "-i", "pipe:0",
 
     p2 = subprocess.Popen(["mythffmpeg", "-loglevel", "quiet", "-i", "pipe:0",
 
             "-ar", "8000", "-f", "au", "-ac", kUpmix_Channels, "-"],
 
             "-ar", "8000", "-f", "au", "-ac", kUpmix_Channels, "-"],
 
             stdin = p1.stdout, stdout = subprocess.PIPE)
 
             stdin = p1.stdout, stdout = subprocess.PIPE)
     # Pipe to mausc which will spit out a list of breaks.
+
     # Pipe to silence which will spit out formatted log lines
     p3 = subprocess.Popen([kExe_Mausc] + param.getValues() + [str(commfree)] + [progId],  
+
     p3 = subprocess.Popen([kExe_Silence] + param.getValues() + [str(commfree)] + [progId],
 
     stdin = p2.stdout, stdout = subprocess.PIPE)
 
     stdin = p2.stdout, stdout = subprocess.PIPE)
  
     # Store breaks in the database.
+
     # Process log output
 
     breaks = 0
 
     breaks = 0
 
     level = {'info':MYLOG.INFO, 'debug':MYLOG.DEBUG, 'err':MYLOG.ERR}
 
     level = {'info':MYLOG.INFO, 'debug':MYLOG.DEBUG, 'err':MYLOG.ERR}
Line 1,181: Line 1,179:
 
                 # extract numbers from log  
 
                 # extract numbers from log  
 
                 numbers = re.findall('\d+', info)
 
                 numbers = re.findall('\d+', info)
                 # mark advert in recording
+
                 # mark advert in database
 
                 rec.markup.append(numbers[0], rec.markup.MARK_COMM_START, None)
 
                 rec.markup.append(numbers[0], rec.markup.MARK_COMM_START, None)
 
                 rec.markup.append(numbers[1], rec.markup.MARK_COMM_END, None)
 
                 rec.markup.append(numbers[1], rec.markup.MARK_COMM_END, None)
Line 1,199: Line 1,197:
  
 
     # Signal comflagging has finished
 
     # Signal comflagging has finished
     if commfree:
+
     rec.commflagged = 3 if commfree else 1
        rec.commflagged = 3
 
    else:
 
        rec.commflagged = 1
 
 
     rec.update()
 
     rec.update()
  
Line 1,212: Line 1,207:
 
{{Code box|Makefile|
 
{{Code box|Makefile|
 
<pre>
 
<pre>
CC=g++
+
CC= g++
CFLAGS=-c -Wall -std=c++0x
+
CFLAGS= -c -Wall -std=c++0x
LDFLAGS=
 
 
INCPATH = -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtNetwork -I/usr/include/qt4/QtSql -I/usr/include/qt4 -I/usr/include/mythtv
 
INCPATH = -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtNetwork -I/usr/include/qt4/QtSql -I/usr/include/qt4 -I/usr/include/mythtv
 
LIBPATH = -L/usr/lib -L/usr/lib/i386-linux-gnu
 
LIBPATH = -L/usr/lib -L/usr/lib/i386-linux-gnu
Line 1,220: Line 1,214:
 
PREFIX = /usr/local/bin
 
PREFIX = /usr/local/bin
  
all: silence.cpp catagrower.cpp silence catagrower
+
.PHONY: clean install
 +
 
 +
all: silence catagrower
 
 
 
catagrower: catagrower.o
 
catagrower: catagrower.o
$(CC) $(LDFLAGS) catagrower.o -o $(PREFIX)/$@
+
$(CC) catagrower.o -o $@
 
 
 
silence: silence.o
 
silence: silence.o
$(CC) $(LDFLAGS) silence.o -o $(PREFIX)/$@ $(LIBPATH) $(LIBS)
+
$(CC) silence.o -o $@ $(LIBPATH) $(LIBS)
  
 
.cpp.o:
 
.cpp.o:
 
$(CC) $(CFLAGS) $(INCPATH) $< -o $@
 
$(CC) $(CFLAGS) $(INCPATH) $< -o $@
  
clean:
+
install: silence catagrower silence.py
rm -f $(PREFIX)/silence $(PREFIX)/catagrower *.o
+
install -p -t $(PREFIX) $^
 +
 
 +
clean:
 +
-rm -f silence catagrower *.o
 
</pre>
 
</pre>
 
}}
 
}}

Revision as of 13:10, 11 March 2013


Author Hippo
Description A python program based on Mythcommflag-wrapper (thank you Cowbut) that can be used on UK FreeviewHD channels and probably others.
Supports Version25.png  Version26.png 


Original version

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)
  • 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%'

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. catagrower takes about 1% and could be a lot better if made less portable.

Script.png catagrower.c

/* 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;
}


Script.png mausc.c

/* 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) {
  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);
}


Script.png mausc-wrapper

#!/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()

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 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

  • 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. 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/

MythPlayer Interaction

Commercial markups are stored in the Myth database. The script writes to the database (via the Python bindings) as commercials are detected. However MythPlayer only reads them from the database once, when playback starts. Thus it will not be aware of any commercials that have been detected after playback started. This situation occurs mainly when watching programmes whilst they are still recording.

MythPlayer is capable of being notified of newly flagged commercials via messages. However to do this, the script needs to be built with Myth & Qt header files, which are not usually installed on packaged Myth installations such as MythBuntu. It is possible to install the requisite headers on such systems. However I am not familiar enough with them to comment on the wisdom of doing so. I believe it is safe but be aware that the packages also contain libraries - updates could break Myth if they are not synchronised correctly.

If you do not install the headers and watch in-progress recordings (whilst they are being flagged), then periodically quitting playback and re-starting it will refresh the commercial markups.

As presented, the script does not need the headers and will build on packaged systems. If you have installed the headers then uncomment the first line of silence.cpp so that USE_HEADERS is defined. This will enable the messaging functionality.

Currently adverts are flagged <maxsep> after they finishes. An experimental feature enables flagging <mindetect> after an advert starts, which may be useful when watching close to real-time. However, it is currently ineffective because MythPlayer prohibits comm-skipping close to programme end.

Ideally MythPlayer notification should be done via Python - I'm investigating this.

Requirements

  • Compilation environment (gcc, make) - install package build-essential
  • libsndfile for reading audio samples - install package libsndfile-dev
  • Optionally, Myth & Qt header files in /usr/include for communicating with MythPlayer. See #MythPlayer Interaction. These are not usually installed by packaged versions of Myth, ie. Mythbuntu, but can be found in packages libmyth-dev and libqt4-dev.

Building

  • Copy catagrower.cpp, silence.cpp, silence.py & Makefile to a new directory and cd there.
  • Modify silence.cpp if you have headers installed. See #MythPlayer Interaction
  • Build the silence & catagrower executables 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.
  • If using the headers, theoretically you should rebuild after every Myth update. However, the headers used rarely change so the script will probably continue to run.

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.
  • 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 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% %VERBOSELEVEL% --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% %VERBOSELEVEL% --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"

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

Script.png 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  

TroubleShooting

  • If you get "Local access to recording not found" 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.
  • If you're using headers and the script stops working after updating Myth, then ensure the headers are up-to-date and rebuild.


Script.png catagrower.cpp

 
/* Copyright 2012 Crackers Phipps. */
/* Public domain. */

/* 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> <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) {

  /* Check usage. */
  if (3 != 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);
  }
  const int timeout = atoi(argv[2]);

#define BUFFSIZE 4096
  int timer = timeout;
  char buffer[BUFFSIZE];
  int bytes;
  while (timer > 0) {
    while (0 != (bytes = read(fd, buffer, BUFFSIZE))) {
      if (-1 == write (STDOUT_FILENO, buffer, bytes)){
          fprintf(stderr, "Write failed.\n");
          exit(3);
        }
      timer = timeout;
    }
    sleep(1);
    timer--;
  }
  return 0;
}


Script.png silence.cpp

// Based on mausc.c by Tinsel Phipps.
// v1.0 Roger Siddons
// v2.0 Roger Siddons: Flag clusters asap, fix segfaults, optional headers
// Public domain. Requires libsndfile, libQtCore, libmythbase-0.x, libmyth-0.x
// Detects commercial breaks using clusters of audio silences

// Uncomment this if you have header files for Myth & Qt installed in /usr/include
// It enables MythPlayer update messages (for watching a programme whilst it is commflagging)
//#define USE_HEADERS 1

// Experimental: Only effective with a modified MythPlayer that allows comm-skipping close to prog end.
// If true, MythPlayer is notified as soon as an advert starts, then again as the advert grows in size.
// If false, MythPlayer will only be notified once per advert, shortly after the advert has finished
const bool kUseAggressiveFlagging = false;

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

#ifdef USE_HEADERS
#include <mythcorecontext.h>
#include <mythcontext.h>
#include <mythversion.h>
#include <programtypes.h>
#include <QCoreApplication>
#endif

#define DELIMITER '@' // must correlate with python wrapper

typedef unsigned frameNumber_t;
typedef unsigned frameCount_t;

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

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
int 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
int commfree;                   // bool: true if prog originates from a comm-free channel
char progId[40];                // programme ident: should be no bigger than "cccc_yyyy-mm-ddThh:mm:ss+hh:mm"

void usage()
{
    error("Usage: silence <threshold> <minquiet> <mindetect> <minlength> <maxsep> <pad> <commfree> <progid>", 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("<commfree> : (int)    1 if prog is comm-free, 0 otherwise.", false);
    error("<progid>   : (string) chan_starttime of program (for player updates).", false);
    error("An AU format file should be fed into this program.", false);
    error("Example: silence -75 0.1 5 60 90 0 1004_20121003090000 < audio.au");
}

void parse(int argc, char **argv)
// Parse args and convert to useable values (frames)
{
    if (9 != 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], "%f", &argThreshold))
        error("Could not parse threshold option into a number");
    if (1 != sscanf(argv[2], "%f", &argMinQuiet))
        error("Could not parse minquiet option into a number");
    if (1 != sscanf(argv[3], "%f", &argMinDetect))
        error("Could not parse mindetect option into a number");
    if (1 != sscanf(argv[4], "%f", &argMinLength))
        error("Could not parse minlength option into a number");
    if (1 != sscanf(argv[5], "%f", &argMaxSep))
        error("Could not parse maxsep option into a number");
    if (1 != sscanf(argv[6], "%f", &argPad))
        error("Could not parse pad option into a number");
    if (1 != sscanf(argv[7], "%d", &commfree))
        error("Could not parse commfree option into a number");
    if (1 != sscanf(argv[8], "%s", progId))
        error("Could not parse progid option into a string");

    /* 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("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 flagged\n",
           DELIMITER);
    printf("info%c           Start - End    Start - End      Duration         Interval    Level/Count\n", DELIMITER);
    printf("info%c          frame - frame (mmm:ss-mmm:ss) frame (mm:ss.s)  frame (mmm:ss)\n", DELIMITER);
}
}

namespace Comms
// Manages MythPlayer communications
{
#ifdef USE_HEADERS
QString updateMessage = "COMMFLAG_UPDATE "; // Player update message
#endif

void initialise(int argc, char **argv)
{
#ifdef USE_HEADERS
    // Require Myth context for sending player update messages
    QCoreApplication q(argc, argv);
    QCoreApplication::setApplicationName("silence");

    MythContext* gContext = new MythContext(MYTH_BINARY_VERSION);

    if (!gContext->Init( false, /*use gui*/
                         false, /*prompt for backend*/
                         false, /*bypass auto discovery*/
                         false)) /*ignoreDB*/
        error("Myth Context initialisation failed");

    gCoreContext->ConnectToMasterServer();

    // construct player update message
    updateMessage += QString(Arg::progId) + ' ';
#endif
}

void send(frameNumber_t start, frameNumber_t end, bool completed = false)
// Sends list of all commbreaks defined so far
{
#ifdef USE_HEADERS
    // requires comma seperator unless it's first advert
    QString sep = (updateMessage.endsWith(' ') ? "" : ",");
    // build new advert markups
    QString newBreak = QString("%1%2:%3,%4:%5").arg(sep).arg(start).arg(MARK_COMM_START)
            .arg(end).arg(MARK_COMM_END);

    if (!completed || (completed && !kUseAggressiveFlagging)) {
        // send completed breaks followed by the one being built
        gCoreContext->SendMessage(updateMessage + newBreak);
        printf("debug%c  Sent %s\n", DELIMITER, (updateMessage + newBreak).toAscii().constData());
    }
    if (completed)
        // append completed break to message
        updateMessage += newBreak;
#endif
}
}

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 -threshold)) {
    fprintf(stderr, "Could not parse threshold option into a number.\n");
    usage(argv[0]);
    exit(2);
  }
  if (1 != sscanf(argv[2], "%f",  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
// Stores 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);
    }
};

ClusterList* clist; // List of completed silences & clusters

Silence* currentSilence; // the silence currently being detected/built
Cluster* currentCluster; // the cluster currently being built

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%c %7s %6d-%6d (%3d:%02ld-%3d:%02ld), %4d (%2d:%04.1f), %5d (%3d:%02ld), [%7d]\n",
           err, DELIMITER, 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("debug", currentSilence->state_log[currentSilence->state], "Silence",
               currentSilence->start, currentSilence->end,
               currentSilence->interval, currentSilence->power);

        // flag player asap for clusters at final state
        if (kUseAggressiveFlagging && currentCluster->state > Cluster::unset)
            Comms::send(currentCluster->padStart, currentCluster->padEnd);

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

    // only interested in clusters at final state
    if (currentCluster->state > Cluster::unset)
    {
        // flag player with completed cluster
        Comms::send(currentCluster->padStart, currentCluster->padEnd, true);
        // log cut
        report("cut", '=', "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
{
    /* Check the input is an audiofile. */
    SF_INFO metadata;
    SNDFILE* input = sf_open_fd(STDIN_FILENO, SFM_READ, &metadata, SF_FALSE);
    if (NULL == input) {
        sf_perror(NULL);
        return sf_error(NULL);
    }

    Arg::parse(argc, argv);

    Comms::initialise(argc, argv);

    /* 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) {
        perror(NULL);
        return errno;
    }

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

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

    // 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)))
    {
        frames++;

        // determine average audio level in this frame
        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 (if prog 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();
    }
}


Script.png silence.py

#!/usr/bin/env python
# Build a skiplist from silence in the audio track.
# Roger Siddons v1.0
# Roger Siddons v2.0 Fix progid for job/player messages

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

kExe_Catagrower = '/usr/local/bin/catagrower'
kExe_Silence    = '/usr/local/bin/silence'
kUpmix_Channels = '1'
kInput_Timeout  = '60'

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

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

    def log(self, msg, level=MythTV.MythLog.INFO):
        "Log message"
        # prepend string to msg so that rsyslog routes it to correct 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(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 = map(self._validate, self.argname, vals)
            # 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)))

    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 = map(self._validate, self.argname, vals[1:min(len(vals),len(self.argname))])
                            # 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)))
                            break
                else:
                    self.logger.log('No preset found for "' + title + '" or "' + callsign + '"')
        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 self.argdict.values()]

def main():
    "Commflag a recording"

    # 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', help='Use chanid for manual operation')
    parser.add_argument('--starttime', help='Use starttime for manual operation')
    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()

    db = MythTV.MythDB()
    logger = MYLOG(db)

    if args.jobid:
        job = MythTV.Job(args.jobid, db)
        chanid = job.chanid
        starttime = job.starttime
        timeout = kInput_Timeout
    elif args.chanid and args.starttime:
        job = None
        chanid = args.chanid
        starttime = args.starttime
        timeout = '1'
    else:
        logger.log('Both chanid and starttime must be specified', MYLOG.ERR)
        sys.exit(1)

    # get recording
    try:
        rec = MythTV.Recorded((chanid, starttime), db)
    except:
        if job:
            job.update({'status':job.ERRORED, 'comment':'ERROR: Could not find recording.'})
        logger.log('Could not find recording', MYLOG.ERR)
        sys.exit(1)

    channel = MythTV.Channel(chanid, db)

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

    commfree = 1 if rec.commflagged == 3 else 0
    if commfree:
        logger.log('--- Comm-free programme - will detect pre-roll & post-roll adverts only')

    sg = MythTV.findfile(rec.basename, rec.storagegroup, db)
    if sg is None:
        if job:
            job.update({'status':job.ERRORED, 'comment':'ERROR: Local access to recording not found.'});
        logger.log('Local access to recording not found', MYLOG.ERR)
        sys.exit(1)

    # player update message needs prog id (with time in Qt::ISODate format)
    progId = str(chanid) + '_' + str(starttime).replace(' ','T')

    # 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)

    infile = os.path.join(sg.dirname, rec.basename)

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

    # Write out the file contents and keep going till recording is finished.
    p1 = subprocess.Popen([kExe_Catagrower, infile, timeout], stdout = subprocess.PIPE)
    # Pipe through ffmpeg 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 silence which will spit out formatted log lines
    p3 = subprocess.Popen([kExe_Silence] + param.getValues() + [str(commfree)] + [progId],
    stdin = p2.stdout, stdout = subprocess.PIPE)

    # Process log output
    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 
                numbers = re.findall('\d+', info)
                # mark advert in database
                rec.markup.append(numbers[0], rec.markup.MARK_COMM_START, None)
                rec.markup.append(numbers[1], rec.markup.MARK_COMM_END, None)
                rec.update()
                breaks += 1
                logger.log(info)
            else:
                # use warning for unexpected log levels
                logger.log(info, level.get(flag, MYLOG.WARNING))
        else:
           break

    if job:
        job.update({'status':272,
                    'comment':'Audio commflag detected %s breaks.' % breaks});
    logger.log('Audio commflag detected %s breaks.' % breaks)

    # Signal comflagging has finished
    rec.commflagged = 3 if commfree else 1
    rec.update()

if __name__ == '__main__':
    main()


Script.png Makefile

CC= g++
CFLAGS= -c -Wall -std=c++0x
INCPATH = -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtNetwork -I/usr/include/qt4/QtSql -I/usr/include/qt4 -I/usr/include/mythtv
LIBPATH = -L/usr/lib -L/usr/lib/i386-linux-gnu
LIBS = -lsndfile -lQtCore -lmythbase-0.26 -lmyth-0.26
PREFIX = /usr/local/bin

.PHONY: clean install

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

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

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

clean: 
	-rm -f silence catagrower *.o