[FFmpeg-user] Audio stream missing

[John Pitney]

On Mon, Jan 2, 2012 at 6:24 PM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
> John Pitney <john <at> pitney.org> writes:
>
>> > ffmpeg -i dvd_rip.vob -map 0:1 out1.wav -map 0:2 out2.wav -map 0:3 out3.wav
>> > -map 0:4 out4.wav
>> > Assuming this works at all, do any of the resulting wav files contain audio?
>>
>> Yes, out[1234].wav each contain the correct audio stream.
>
> Then please test with audio encoders to find out the exact problem.
> (broken libfaac installation?)
>
> ffmpeg -i dvd_rip.vob out.ac3
> ffmpeg -i dvd_rip.vob out.aac

Both of those commands create files with the correct audio stream.

However, if I add -t 60 to try encoding only the first minute, I get
no output.  The file dvd_rip.vob is a single chapter from somewhere in
the middle of a DVD.  When I play it with mplayer, the timestamp
starts counting up at 00:55:51 or so.  It's only 6 or 7 minutes long.

--- begin paste ---
$ ffmpeg -i dvd_rip.vob -t 60 out.aac
ffmpeg version N-36295-gb6ffcee, Copyright (c) 2000-2011 the FFmpeg developers
  built on Dec 30 2011 20:33:51 with gcc 4.6.1 20110908 (Red Hat 4.6.1-9)
  configuration: --enable-gpl --enable-libfaac --enable-libmp3lame
--enable-libx264 --enable-nonfree
  libavutil      51. 33.100 / 51. 33.100
  libavcodec     53. 49.100 / 53. 49.100
  libavformat    53. 29.100 / 53. 29.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 55.100 /  2. 55.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  5.100 /  0.  5.100
  libpostproc    51.  2.100 / 51.  2.100
[mpeg2video @ 0x1e22c60] ac-tex damaged at 11 7
[mpeg2video @ 0x1e22c60] Warning MVs not available
[mpeg2video @ 0x1e22c60] concealing 1035 DC, 1035 AC, 1035 MV errors
[mpeg @ 0x1e1c7a0] max_analyze_duration 5000000 reached at 5024000

Seems stream 0 codec frame rate differs from container frame rate:
59.94 (60000/1001) -> 59.94 (60000/1001)
Input #0, mpeg, from 'dvd_rip.vob':
  Duration: 01:02:07.82, start: 0.280633, bitrate: 668 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480
[SAR 32:27 DAR 16:9], 9800 kb/s, 23.94 fps, 59.94 tbr, 90k tbn, 59.94
tbc
    Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), s16, 448 kb/s
    Stream #0:2[0x81]: Audio: ac3, 48000 Hz, 5.1(side), s16, 384 kb/s
    Stream #0:3[0x82]: Audio: ac3, 48000 Hz, 5.1(side), s16, 384 kb/s
    Stream #0:4[0x83]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
File 'out.aac' already exists. Overwrite ? [y/N] y
Output #0, adts, to 'out.aac':
  Metadata:
    encoder         : Lavf53.29.100
    Stream #0:0: Audio: aac, 48000 Hz, 5.1(side), s16, 128 kb/s
Stream mapping:
  Stream #0:1 -> #0:0 (ac3 -> libfaac)
Press [q] to stop, [?] for help
size=       0kB time=00:00:00.00 bitrate=   0.0kbits/s
video:0kB audio:0kB global headers:0kB muxing overhead -nan%
Output file is empty, nothing was encoded (check -ss / -t / -frames
parameters if used)
--- end paste ---

Best regards,
John