Is it possible to extract an audio track from the .VOB files (or a concatenated file) of a DVD with ffmpeg? The things I tried don't work and the concatenated .VOB seems broken. See how the audio tracks have 0 channels, and the movie last 2h22min.
$ ffmpeg -i all.VOB -map 0:2 -ar 48k -c copy out2.ac3
[mp3float @ 0x577426c4d6c0] Header missing
Last message repeated 555 times
[mpeg @ 0x577426c4a540] start time for stream 2 is not set in estimate_timings_from_pts
[mpeg @ 0x577426c4a540] stream 2 : no TS found at start of file, duration not set
[mpeg @ 0x577426c4a540] stream 3 : no TS found at start of file, duration not set
[mpeg @ 0x577426c4a540] stream 4 : no TS found at start of file, duration not set
[mpeg @ 0x577426c4a540] Could not find codec parameters for stream 2 (Audio: ac3, 0 channels): unspecified sample format
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
[mpeg @ 0x577426c4a540] Could not find codec parameters for stream 3 (Audio: ac3, 0 channels): unspecified sample format
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
[mpeg @ 0x577426c4a540] Could not find codec parameters for stream 4 (Audio: ac3, 0 channels): unspecified sample format
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, mpeg, from 'all.VOB':
Duration: 01:12:02.63, start: 0.128389, bitrate: 13054 kb/s
Stream #0:0[0x1bf]: Data: dvd_nav_packet
Stream #0:1[0x1e0]: Audio: mp3, 24000 Hz, stereo, fltp, 32 kb/s
Stream #0:2[0x80]: Audio: ac3, 0 channels
Stream #0:3[0x81]: Audio: ac3, 0 channels
Stream #0:4[0x82]: Audio: ac3, 0 channels