Mythtranscode swaps audio tracks

[Jim Stichnoth <stichnot@…>]

I sometimes record from an ATSC station that has some narrative on the second audio track that is unrelated to the program. When I do a lossless transcode, the track order becomes reversed, and one hears this narrative instead (so it is quite obvious that the wrong track is being played by default).

For the original file, "Select Audio Track" from the OSD menu gives choices "1: English AC3 2ch" and "2: French AC3 2ch". After transcoding, the options are "1: Undetermined AC3 2ch" and "2: Undetermined AC3 2ch".

Here is what I think is the relevant portion of the mythtranscode output, applied to a 100MB sample of the original file:

$ mythtranscode -v all -i thomas_100mb.mpg -o thomas_100mb_xcode.mpg --video --mpeg2
[...]
2010-03-13 19:47:59.432 Input #0, mpegts, from '/storage2/videos/test/thomas_100mb.mpg':
2010-03-13 19:47:59.432   Duration: 00:01:26.28, start: 23668.158511, bitrate: 9722 kb/s
2010-03-13 19:47:59.433     Stream #0.0[0x31]: Video: mpeg2video, yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], 19392 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
2010-03-13 19:47:59.433     Stream #0.1[0x34](eng): Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
2010-03-13 19:47:59.433     Stream #0.2[0x35](fre): Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
[...]
2010-03-13 19:48:02.262 Input #0, mpeg, from 'thomas_100mb_xcode.mpg':
2010-03-13 19:48:02.262   Duration: 00:01:25.09, start: 0.360000, bitrate: 9679 kb/s
2010-03-13 19:48:02.262     Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], 19392 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
2010-03-13 19:48:02.262     Stream #0.1[0x81]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
2010-03-13 19:48:02.262     Stream #0.2[0x80]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
[...]

Mythtranscode doesn't have a --version flag, but here is the output for mythbackend:

$ mythbackend --version
Please include all output in bug reports.
MythTV Version   : 23734M
MythTV Branch    : trunk
Network Protocol : 56
Library API      : 0.23.20100310-1
QT Version       : 4.5.2
Options compiled in:
 linux release using_oss using_alsa using_backend using_dvb using_fribidi using_frontend using_hdhomerun using_hdpvr using_iptv using_ivtv using_joystick_menu
 using_lirc using_mheg using_opengl_video using_opengl_vsync using_qtdbus using_qtwebkit using_v4l using_x11 using_xrandr using_xv
 using_bindings_perl using_bindings_python using_opengl using_vdpau using_ffmpeg_threads using_live using_mheg

100MB sample of the original: ​https://docs.google.com/leaf?id=0BxETmfuHvGPQMWFkMGIwOTctMjY4Ny00NDQ2LWFkZWYtYTkzNWQ0NTJhMTc4&hl=en

Result of transcoding the 100MB sample: ​https://docs.google.com/leaf?id=0BxETmfuHvGPQOGE5YTFmYzYtMmVlZS00YzI0LThmNDMtZmZiYTdhMTNlYzcx&hl=en

[sphery]

dup of #6626 .