[mythtv-commits] Ticket #8435: Mythtranscode uses the wrong audio track in the output

[MythTV]

#8435: Mythtranscode uses the wrong audio track in the output
------------------------------+---------------------------------------------
 Reporter:  anonymous         |       Owner:  ijr       
     Type:  defect            |      Status:  new       
 Priority:  minor             |   Milestone:  unknown   
Component:  MythTV - General  |     Version:  0.22-fixes
 Severity:  medium            |     Mlocked:  0         
------------------------------+---------------------------------------------
 I'm having an issue that is similar to ticket #6626.  A couple of times a
 week (especially for certain shows), mythtranscode using a Lossless
 profile generates a output file with the wrong audio track.

 {{{
 mythtranscode -v all --profile Lossless --video -i survivor.mpg -o
 survivor-transcode.mpg
 }}}

 The input file is an MPEG2-TS (from HRHomeRun) with 2 audio tracks.  In
 the original, audio track #1 is 6 channel AC3 while audio track #2 is 2
 channel.  Audio track #2 is easy to identify  since it plays back with a
 slight A/V sync issue.  Audio track #1 is in sync (and 5.1 of course):

 {{{
 2010-05-09 06:25:17.348 Opening /data/recordings/RecordedTV/survivor.mpg
 2010-05-09 06:25:17.389 Input #0, mpegts, from
 '/data/recordings/RecordedTV/survivor.mpg':
 2010-05-09 06:25:17.390   Duration: 00:59:56.91, start: 65258.976767,
 bitrate: 11163 kb/s
 2010-05-09 06:25:17.390     Stream #0.0[0x31]: Video: mpeg2video, yuv420p,
 1920x1080 [PAR 1:1 DAR 16:9], 1001/60000, 65000 kb/s, 59.94 tbr, 90k tbn,
 59.94 tbc
 2010-05-09 06:25:17.390     Stream #0.1[0x34]: Audio: ac3, 48000 Hz, 5.1,
 s16, 384 kb/s
 2010-05-09 06:25:17.390     Stream #0.2[0x35]: Audio: ac3, 48000 Hz,
 stereo, s16, 128 kb/s
 2010-05-09 06:25:17.390     Stream #0.3[0x120]: Data: 0x0101
 2010-05-09 06:25:17.390 Skipping unsupported codec 2 on stream 3
 2010-05-09 06:25:17.400 1920x1088 P:900900 02:22:31:004 #0 fl:2IT_0 pos:
 376
 2010-05-09 06:25:17.400 Found 1st valid video frame
 }}}

 What makes this ticket different from #6626 is the log seems to show that
 audio track #1 is being selected properly:

 {{{
 2010-05-09 06:25:17.305 Using 1 CPUs for decoding
 2010-05-09 06:25:17.305 AFD: InitVideoCodec() 0x8362960 id(MPEG2VIDEO)
 type (Video).
 2010-05-09 06:25:17.305 detectInterlace(Detect Scan, Interlaced Scan,
 29.97, 1080) ->Interlaced Scan
 2010-05-09 06:25:17.305 AFD: EIA-608 caption 1 is in the English language.
 2010-05-09 06:25:17.305 AFD: Using ffmpeg for video decoding
 2010-05-09 06:25:17.305 AFD: Looking for decoder for MPEG2VIDEO
 2010-05-09 06:25:17.305 AFD: Opened codec 0x8362960, id(MPEG2VIDEO)
 type(Video)
 2010-05-09 06:25:17.305 AFD: Stream #1, has id 0x34 codec id AC3, type
 Audio, bitrate 384000 at 0x8362d20
 2010-05-09 06:25:17.306 AFD: codec AC3 has 6 channels
 2010-05-09 06:25:17.306 AFD: Looking for decoder for AC3
 2010-05-09 06:25:17.306 AFD: Opened codec 0x8367400, id(AC3) type(Audio)
 2010-05-09 06:25:17.306 AFD: Audio Track #1 is A/V stream #1 and has 6
 channels in the Undetermined language(7695972).
 2010-05-09 06:25:17.306 AFD: Stream #2, has id 0x35 codec id AC3, type
 Audio, bitrate 128000 at 0x83677c0
 2010-05-09 06:25:17.306 AFD: codec AC3 has 2 channels
 2010-05-09 06:25:17.306 AFD: Looking for decoder for AC3
 2010-05-09 06:25:17.307 AFD: Opened codec 0x8367990, id(AC3) type(Audio)
 2010-05-09 06:25:17.307 AFD: Audio Track #2 is A/V stream #2 and has 2
 channels in the Undetermined language(7695972).
 2010-05-09 06:25:17.307 AFD: Stream #3, has id 0x120 codec id DVB_VBI,
 type Data, bitrate 0 at 0x8367f30
 2010-05-09 06:25:17.313 AFD: data codec (Data)
 2010-05-09 06:25:17.313 RingBuf(/data/recordings/RecordedTV/survivor.mpg):
 CalcReadAheadThresh(0 KB)
                          -> threshhold(64 KB) min read(0 KB) blk size(32
 KB)
 2010-05-09 06:25:17.313 AFD: Trying to select audio track (w/lang)
 2010-05-09 06:25:17.313 AFD: Trying to select audio track (wo/lang)
 2010-05-09 06:25:17.313 AFD: Selected track 1: Undetermined AC3 5.1ch (A/V
 Stream #1)
 2010-05-09 06:25:17.313 AFD: Initializing audio parms from audio track #1
 2010-05-09 06:25:17.313 AFD: Audio format changed
                         from id(NONE)    -1Hz -1ch   0bps    ; id(NONE)
 -1Hz -1ch   0bps
                         to   id( AC3) 48000Hz  6ch  16bps    ; id( AC3)
 48000Hz  2ch  16bps
 2010-05-09 06:25:17.313 Dec: Selected track #1 in the English
 language(6647399)
 2010-05-09 06:25:17.313 Dec: Resyncing position map. posmapStarted = 0
 livetv(0) watchingRec(0)
 }}}

 The output file contains a single audio track.  However, it's the 2
 channel audio with the A/V sync issues.  So, it appears that audio track
 #2 is actually being used.

 I'll be happy to attach portions of the original file or output file if it
 would help.

 Thank you for your help!

-- 
Ticket URL: <http://svn.mythtv.org/trac/ticket/8435>
MythTV <http://www.mythtv.org/>
MythTV