id,summary,reporter,owner,description,type,status,priority,milestone,component,version,severity,resolution,keywords,cc,mlocked 11639,Dynamic PMT: Audio lost after transcode,oli.henning@…,,"Since a few weeks i have a problem with mythtranscode: Audio is completly lost after transcoding. Perhaps this is the same or similar to http://code.mythtv.org/trac/ticket/7118 == Details == - Recording with DVB-C - Problem occurs just on one specific channel: ""ORF 1"" (prime channel of austria). - Recorded in switzerland, cable-provider ""UPC Cablecom"" - Problem does not occur on every recording - so the problem is not ""stable"" - Just using ""lossless MPEG-2"" transcoding to cut-off commerials. - No audio- and no video-recompression (so it's quite fast) - Before the transcoding all audio-channels are present in mythfrontend - Changes in audio-streams-combinations within recoding is recognized in mythfrontend (e.g. not from the beginning but from somewhere in the middle of the recoding there is an AC3-stream) == Example-File to reproduce == https://dl.dropboxusercontent.com/u/517875/2109_20130701213000.mpg I cutted of the first 310'200'000 Bytes. This are exactly 1'650'000 TS-Packets (each 188 Bytes). So this is just the first ~9 minutes of the original recording. '''Interesting fact''': If the file would be just the first 1'600'000 TS-Packets, then {{{mythtranscode}}} will __not__ have the audio-loss-problem. This is the reason why the test-file-to-reproduce has to be so big. == LOG-Output of mythtranscode == {{{ (my_av_print) Input #0, mpegts, from '/mnt/mythtvRecordings/2109_20130701213000.mpg': (my_av_print) Duration: N/A, bitrate: N/A (my_av_print) Stream #0:0[0x90]: Video: mpeg2video, 90k tbn (my_av_print) Stream #0:1[0x91](ger): Audio: mp3, 0 channels (my_av_print) Stream #0:2[0x9b](ger): Audio: ac3, 0 channels (my_av_print) Stream #0:3[0xae](ger): Subtitle: dvb_teletext (InitAV) Skipping invalid audio stream: 1 (InitAV) Skipping invalid audio stream: 2 }}} You can see, that mythtranscode has some problems in identifying the stream-content: - mythtranscode could not detect the recording-duration (just logs ""N/A"") - mythtranscode could not detect details of the video-stream (pixel-format, frame-size, frame-rate, ...) - mythtranscode detected the first audio-stream as beeing ""mp3"". But actually it's a normal ""mp2"" audio-stream (analyzed with avprobe) To compare: the log of a 'normal' transcoding: {{{ (my_av_print) Input #0, mpegts, from '/mnt/mythtvRecordings/2102_20130629193300.mpg': (my_av_print) Duration: 00:44:56.88, start: 13209.723733, bitrate: 7099 kb/s (my_av_print) Stream #0:0[0x50]: Video: mpeg2video (Main), yuv420p, 720x576 [SAR 64:45 DAR 16:9], 15000 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc (my_av_print) Stream #0:1[0x51](deu): Audio: mp2, 48000 Hz, stereo, s16, 192 kb/s (my_av_print) Stream #0:2[0x52](eng): Audio: mp2, 48000 Hz, stereo, s16, 192 kb/s (my_av_print) Stream #0:3[0x6e](deu): Data: dvb_vbi (InitAV) Skipping unsupported codec 2 on stream 3 }}} On request i can do further investigations. Perhaps you have to name me some analyze-tools.",Bug Report - General,closed,minor,0.27.2,MythTV - Mythtranscode,0.26-fixes,medium,Duplicate,transcode audio,,0