Mythcutprojectx

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Script to preprocess mpeg2 recordings from dvb-t. Applying the cutlist via Project-X within MythArchive? sometimes gives the wrong sound channel and means that the size of the final file is not known when the recordings are selected. This script tells the user what PIDs are present and requires him/her to specify two: one video, one audio. The cutlist is not applied with single-frame accuracy but I have found it robust and 'good enough'. I have had very few failures when the script has been used on the original recording; it seemed less reliable when used on recordings that had been preprocessed using mencoder.

The script (still called mythcutprojectx) uses ideas from scripts found in the mythtv lists: mythcutprojectx and pxcut.sh


#!/bin/sh -e

# Copyright (C) 2010 John Pilkington 
# Largely based on scripts posted by Tino Keitel and Kees Cook in the Mythtv lists.

# Usage: ./mythcutprojectx <recording>
# <recording> is an mpeg2 file recorded by MythTV with a valid DB entry.

# This script is essentially a replacement for the 'lossless' mpeg2 mythtranscode.
# It will pass the recording and the MythTV cutlist to ProjectX.
# If the cutlist is empty the entire recording will be processed.
# It uses ffmpeg to report what streams are present and
# asks the user to input the PIDs of the video and one audio stream.
# It uses ProjectX to demux and mplex (from mjpegtools) to remux.
# Output format is DVD compliant without nav packets.
# It then clears the cutlist, updates the filesize in the database and rebuilds the seek table.
# The result is apparently acceptable as a recording within MythTV and as input to MythArchive.
# The ProjectX log file is kept. Other tempfiles are deleted.

# The script needs to be edited to define some local variables.

####################

# Variables RECDIR1, RECDIR2, TEMPDIR1, TEMPDIR2, PROJECTX, PASSWD need to be customised.
# RECDIR1 and TEMPDIR1 should if possible be on different drive spindles.  Likewise RECDIR2 and TEMPDIR2.

RECDIR1=/mnt/f10store/myth/reca
TEMPDIR1=/mnt/sam1/tempb

RECDIR2=/mnt/sam1/recb
TEMPDIR2=/mnt/f10store/myth/tempa

#PROJECTX=/path/to/ProjectX.jar (or to a link to it)
PROJECTX=~/projectx

#PASSWD=`grep "^DBPassword" ~/.mythtv/mysql.txt | cut -d '=' -f 2-`
PASSWD=mythtv

#################

if test "$1" = "-h" || test "$1" = "--help" ; then
echo "Usage: ./mythcutprojectx <recording>"
echo "<recording> is an mpeg2 file recorded by MythTV with a valid DB entry."
echo "e.g. 1234_20100405123400.mpg in one of the defined RECDIRs"
echo "The output file replaces the input file which is renamed to <recording>.old"
exit 0
fi

# Customize with paths to alternative recording and temp folders

cd $RECDIR1
TEMP=$TEMPDIR1
if  [ ! -f "$1" ] ; then
   cd $RECDIR2
   TEMP=$TEMPDIR2
     if  [ ! -f "$1" ] ; then 
       echo " "$1" not found.  Giving up"
       cd
       exit 1
     fi
fi 

if [ $# -lt 3 ]
then
   echo "Error: needs three arguments. Running  ffmpeg -i "$1" 2>&1 | grep -C 4 Video " 
   echo  
   ffmpeg -i "$1" 2>&1 | grep -C 4 Video
   echo
   echo "Expected Command Line is of the form   ./mythcutprojectx 1234_20070927190000.mpg  0xvvv 0xaaa " 
   echo "                                                         filename_in_DB           vPID  aPID  " 
   cd ~
   exit 1
fi

# chanid and starttime identify the recording in the DB
chanid=`echo "select chanid from recorded where basename=\"$1\";" |
mysql -N -u mythtv  -p$PASSWD mythconverg `

starttime=`echo "select starttime from recorded where basename=\"$1\";" |
mysql -N -u mythtv  -p$PASSWD mythconverg `

# list0 gives start (cut-in) points but omits initial zero if start of recording is wanted; includes eof.
list0=`echo "select mark from recordedmarkup
where chanid=$chanid and starttime='$starttime' and type=0 order by mark;" |
mysql -N -u mythtv  -p$PASSWD mythconverg `
  
# list1 gives start of cut (cut-out points). Has initial zero if start of recording is to be cut 
list1=`echo "select mark from recordedmarkup
where chanid=$chanid and starttime='$starttime' and type=1 order by mark;" |
mysql -N -u mythtv  -p$PASSWD mythconverg `  

echo "CollectionPanel.CutMode=0" > cutlist$$ ;
for i in $list1 ;
do
  if [ $i = "0" ] 
    then  
    list=`echo "select mark from recordedmarkup
    where chanid=$chanid and starttime='$starttime' and type in (0,1) order by mark;" |
    mysql -N -u mythtv  -p$PASSWD mythconverg | tail -n +2 ` 
# tail -n +2 drops the initial zero.
  else
    echo "0" >> cutlist$$
    list=`echo "select mark from recordedmarkup
    where chanid=$chanid and starttime='$starttime' and type in (0,1) order by mark;" |
    mysql -N -u mythtv  -p$PASSWD mythconverg `  
  fi
#  use only the first element of list1, as a switch.
  break
done
 
# find the key frame (mark type 9) right before each cut mark,
# extract the byte offset, write it into the ProjectX cutlist
for i in $list ;
do echo "select offset from recordedseek
  where chanid=$chanid and starttime='$starttime' and type=9 and mark >= $i and mark < ($i + 100)
  order by offset;" |
  mysql -N -u mythtv  -p$PASSWD mythconverg | head -n 1
# for each cycle, head -n 1 yields the first line only.
done >> cutlist$$

echo "list0"
echo $list0
echo
echo "list1"
echo $list1
echo
echo "list"
echo $list
echo
cat cutlist$$
echo

#exit

if  [ -f "$1".old ] ; then
  echo " "$1".old exists.  Giving up"
  exit 1
else
  mv  "$1" "$1".old
# use ProjectX to de-multiplex selected streams with the created cutlist
  ionice -c3 java -jar "$PROJECTX" -name tempcut$$ -id $2,$3 -out $TEMP -cut cutlist$$ "$1".old || :
# and pipe for re-multiplexing to mplex. -f 9 is dvd format without navpacks
  ionice -c3  mplex -o "$1" -V -f 9 $TEMP/tempcut${$}.m2v $TEMP/tempcut${$}.mp2 

# tell mythDB about new filesize and clear myth cutlist
  FILESIZE=`du -b "$1" | cut -f 1`
  if [ "${FILESIZE}" -gt 1000000 ]; then
      echo "running: update recorded set filesize=${FILESIZE} where basename=\"$1\";"
      echo "update recorded set filesize=${FILESIZE} where basename=\"$1\";" | mysql -u mythtv -p$PASSWD mythconverg
      echo "filesize has been reset"
      echo "running: ionice -c3 mythcommflag -f "$1" --clearcutlist"
      ionice -c3 mythcommflag -f "$1" --clearcutlist
      echo "cutlist has been cleared"
  fi

#rebuild seek table
  echo "running: ionice -c3 mythtranscode --mpeg2 --buildindex --showprogress --chanid "$chanid" --starttime "$starttime""
  ionice -c3 mythtranscode --mpeg2 --buildindex --showprogress --chanid "$chanid" --starttime "$starttime"
  echo "seek table has been rebuilt"

  echo "Output file is $1  -  PID streams $2 and $3 copied"
  echo
  rm -f "$1".png
#rm -f $TEMP/tempcut${$}*
  mv $TEMP/tempcut${$}_log.txt $TEMP/$1_pxlog.txt 
  rm -f $TEMP/tempcut${$}.m2v
  rm -f $TEMP/tempcut${$}.mp2
  rm -f cutlist$$
fi

cd
exit 0