ffmpeg -i 20121201_135852.mp4 -vn -c:a pcm_s16le test2.wav -loglevel debug
ffmpeg version 1.0.1 Copyright (c) 2000-2012 the FFmpeg developers
  built on Dec 17 2012 15:56:29 with gcc 4.6.1 (Ubuntu/Linaro 4.6.1-9ubuntu3)
  configuration: --enable-gpl --enable-libfaac --enable-libfdk-aac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-librtmp --enable-libtheora --enable-libvorbis --enable-x11grab --enable-libx264 --enable-nonfree --enable-version3
  libavutil      51. 73.101 / 51. 73.101
  libavcodec     54. 59.100 / 54. 59.100
  libavformat    54. 29.104 / 54. 29.104
  libavdevice    54.  2.101 / 54.  2.101
  libavfilter     3. 17.100 /  3. 17.100
  libswscale      2.  1.101 /  2.  1.101
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x31a7260] Format mov,mp4,m4a,3gp,3g2,mj2 probed with size=2048 and score=100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x31a7260] ISO: File Type Major Brand: isom
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x31a7260] File position before avformat_find_stream_info() is 2729421085
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x31a7260] All info found
rfps: 29.333333 0.016280
rfps: 29.416667 0.012450
rfps: 29.500000 0.009132
    Last message repeated 1 times
rfps: 29.583333 0.006328
    Last message repeated 1 times
rfps: 29.666667 0.004036
    Last message repeated 1 times
rfps: 29.750000 0.002258
    Last message repeated 1 times
rfps: 29.833333 0.000993
    Last message repeated 1 times
rfps: 29.916667 0.000242
    Last message repeated 1 times
rfps: 30.000000 0.000004
    Last message repeated 1 times
rfps: 30.083333 0.000278
    Last message repeated 1 times
rfps: 30.166667 0.001067
    Last message repeated 1 times
rfps: 30.250000 0.002368
rfps: 30.333333 0.004182
rfps: 30.416667 0.006510
rfps: 30.500000 0.009351
rfps: 30.583333 0.012705
rfps: 30.666667 0.016573
rfps: 59.333333 0.016145
rfps: 59.416667 0.012333
rfps: 59.500000 0.009033
rfps: 59.583333 0.006247
rfps: 59.666667 0.003974
rfps: 59.750000 0.002214
    Last message repeated 1 times
rfps: 59.833333 0.000968
    Last message repeated 1 times
rfps: 59.916667 0.000234
    Last message repeated 1 times
rfps: 60.000000 0.000014
    Last message repeated 1 times
rfps: 29.970030 0.000030
    Last message repeated 1 times
rfps: 59.940060 0.000121
    Last message repeated 1 times
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x31a7260] File position after avformat_find_stream_info() is 1425556
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '20121201_135852.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 0
    compatible_brands: isom3gp4
    creation_time   : 2012-12-01 20:20:13
  Duration: 00:21:15.28, start: 0.000000, bitrate: 17121 kb/s
    Stream #0:0(eng), 21, 1/90000: Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080, 1/180000, 16993 kb/s, 29.99 fps, 30 tbr, 90k tbn, 180k tbc
    Metadata:
      creation_time   : 2012-12-01 20:20:13
      handler_name    : VideoHandle
    Stream #0:1(eng), 49, 1/48000: Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, s16, 123 kb/s
    Metadata:
      creation_time   : 2012-12-01 20:20:13
      handler_name    : SoundHandle
[abuffer @ 0x3209fa0] Setting entry with key 'time_base' to value '1/48000'
[abuffer @ 0x3209fa0] Setting entry with key 'sample_rate' to value '48000'
[abuffer @ 0x3209fa0] Setting entry with key 'sample_fmt' to value 's16'
[abuffer @ 0x3209fa0] Setting entry with key 'channel_layout' to value '0x3'
[graph 0 input from stream 0:1 @ 0x320cba0] tb:1/48000 samplefmt:s16 samplerate:48000 chlayout:0x3
[aformat @ 0x320a160] Setting entry with key 'sample_fmts' to value 's16'
Output #0, wav, to 'test2.wav':
  Metadata:
    major_brand     : isom
    minor_version   : 0
    compatible_brands: isom3gp4
    encoder         : Lavf54.29.104
    Stream #0:0(eng), 0, 1/48000: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, stereo, s16, 1536 kb/s
    Metadata:
      creation_time   : 2012-12-01 20:20:13
      handler_name    : SoundHandle
Stream mapping:
  Stream #0:1 -> #0:0 (aac -> pcm_s16le)
Press [q] to stop, [?] for help
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x31a7260] demuxer injecting skip 1024
[aac @ 0x31af480] skip 1024 samples due to side data
[aac @ 0x31af480] skip whole frame, skip left: 0
EOF on sink link output stream 0:0:default.35.9kbits/s
No more output streams to write to, finishing.
size=  239112kB time=00:21:15.28 bitrate=1536.0kbits/s
video:0kB audio:239112kB subtitle:0 global headers:0kB muxing overhead 0.000019%
[AVIOContext @ 0x31af920] Statistics: 42123415 bytes read, 1222 seeks