[FFmpeg-user] audio streams

Carl Eugen Hoyos cehoyos at ag.or.at
Sun Nov 13 13:02:43 CET 2011

Rick C. <rickcorteza <at> gmail.com> writes:

> > The -map option allows you to choose which stream(s) of the input file
> > should be encoded.
> Sorry here's the output below.  I guess there's no choice but to use the -map
> option in this case?


> Input #0, mpeg, from '/Users/mahalko/Desktop/VTS_04_1.VOB':
>   Duration: 00:23:56.44, start: 0.203422, bitrate: 5979 kb/s
>     Stream #0.0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x576 [PAR 64:45
DAR 16:9], 9800 kb/s, 25 fps,
> 25 tbr, 90k tbn, 50 tbc
>     Stream #0.1[0x20]: Subtitle: dvdsub
>     Stream #0.2[0x21]: Subtitle: dvdsub
>     Stream #0.3[0x80]: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
>     Stream #0.4[0x81]: Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s

I agree with you that there are several signs that indicate 0x80 is the track
most users want to encode. Unfortunately, I don't think it is so easy in the
general case, so yes, you will have to provide -map afaict.
(My guess is that 0x81 starts earlier with non-silent sound and this is why
FFmpeg believes it is the more useful audio track. Just a guess.)

Carl Eugen

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