[mythtv] Mytharchive - bad subsid-track mp2 to ac3 conversion

[Paul Harrison]

John Pilkington wrote:
> I just installed the latest ATrpms build: 0.21-175_trunk_r15741.el5.i386
>
> As suggested by the wiki I have Mytharchive converting the two native 
> mp2 audio channels to ac3.  The subsidiary track is garbled in the dvd 
> image - Donald Duck effect.   Same in mplayer and internal .iso player.
>
> With the earlier 15447 build I had noticed that the two audio streams 
> before the remux were both the same size.  I now find that the 
> subsidiary track is garbled on a DVD burned with that build.
>
> I don't think I really need to do the mp2 to ac3 thing - it's just a 
> workaround to help players that can't handle both, and the title music 
> is supplied as ac3.
>
> For the original recording as input after mythtranscode:
>
> $ ffmpeg -i 3009_20080207205900.mpg
>
> Input #0, mpeg, from '3009_20080207205900.mpg':
>    Duration: 00:58:59.3, start: 0.298589, bitrate: 3569 kb/s
>      Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 
> DAR 16:9], 15000 kb/s, 25.00 tb(r)
>      Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, stereo, 256 kb/s
>      Stream #0.2[0x1c1]: Audio: mp2, 48000 Hz, mono, 64 kb/s
>
> and in the working directory:
>
> ffmpeg -i VTS_02_1.VOB
>
> Input #0, mpeg, from 'VTS_02_1.VOB':
>    Duration: 00:38:45.1, start: 0.160000, bitrate: 3694 kb/s
>      Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 
> DAR 16:9], 15000 kb/s, 25.00 tb(r)
>      Stream #0.1[0x80]: Audio: liba52, 48000 Hz, stereo, 192 kb/s
>      Stream #0.2[0x81]: Audio: liba52, 48000 Hz, mono, 192 kb/s
>
> Thanks to Paul H for the recent native-mode patch.
>
> John P
>
>   

I've just tried to reproduce this and it worked OK for me. I had a hard
time finding a recording where the secondary audio track was actually
being used but did eventually find a film with an audio described track
for the second track mono, mp2, 64kb/s just like your original. I chose
not to re-encode the file but did chose to re-encode the audio to ac3
which looks to be what you did and both audio tracks played fine in the
internal player, mplayer and with xine.

If you still have the work directory intact you could look in there for
the ac3 sound track and see if it plays OK.

Paul H.