ffmpeg -i vts_01_1.vob test.flac
ffmpeg version 0.8.6, Copyright (c) 2000-2011 the FFmpeg developers
  built on Dec  2 2011 04:02:09 with gcc 4.6.2
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --enable-shared --cc=x86_64-pc-linux-gnu-gcc --disable-optimizations --disable-static --enable-gpl --enable-postproc --enable-avfilter --disable-stripping --disable-debug --disable-doc --disable-network --disable-vaapi --disable-vdpau --disable-zlib --disable-bzlib --disable-ffplay --disable-encoders --disable-indev=v4l --disable-indev=v4l2 --disable-indev=alsa --disable-indev=oss --disable-indev=jack --disable-outdev=alsa --disable-outdev=oss --disable-amd3dnow --disable-amd3dnowext --disable-altivec --disable-avx --disable-mmx --disable-mmx2 --disable-ssse3 --cpu=core2
  libavutil    51.  9. 1 / 51.  9. 1
  libavcodec   53.  7. 0 / 53.  7. 0
  libavformat  53.  4. 0 / 53.  4. 0
  libavdevice  53.  1. 1 / 53.  1. 1
  libavfilter   2. 23. 0 /  2. 23. 0
  libswscale    2.  0. 0 /  2.  0. 0
  libpostproc  51.  2. 0 / 51.  2. 0
[mpeg @ 0x1526330] max_analyze_duration 5000000 reached at 5000000
Input #0, mpeg, from 'vts_01_1.vob':
  Duration: 00:19:07.30, start: 0.287267, bitrate: 7487 kb/s
    Stream #0.0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x576 [PAR 64:45 DAR 16:9], 8000 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0.1[0xa0]: Audio: pcm_s16be, 48000 Hz, 2 channels, s16, 1536 kb/s
Output #0, flac, to 'test.flac':
    Stream #0.0: Audio: [0][0][0][0] / 0x0000, 48000 Hz, 2 channels, s16, 64 kb/s
Stream mapping:
  Stream #0.1 -> #0.0
Encoder (codec id 86030) not found for output stream #0.0