ffmpeg -i audioStream_0.4772734013386071.flv -ar 22050 foo.mp3
ffmpeg version N-53112-gd686517 Copyright (c) 2000-2013 the FFmpeg developers
  built on May 16 2013 05:24:51 with gcc 4.6 (Debian 4.6.3-1)
  configuration: --prefix=/root/ffmpeg-static/64bit --extra-cflags='-I/root/ffmpeg-static/64bit/include -static' --extra-ldflags='-L/root/ffmpeg-static/64bit/lib -static' --extra-libs='-lxml2 -lexpat -lfreetype' --enable-static --disable-shared --disable-ffserver --disable-doc --enable-bzlib --enable-zlib --enable-postproc --enable-runtime-cpudetect --enable-libx264 --enable-gpl --enable-libtheora --enable-libvorbis --enable-libmp3lame --enable-gray --enable-libass --enable-libfreetype --enable-libopenjpeg --enable-libspeex --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-version3 --enable-libvpx
  libavutil      52. 32.100 / 52. 32.100
  libavcodec     55.  9.100 / 55.  9.100
  libavformat    55.  7.100 / 55.  7.100
  libavdevice    55.  0.100 / 55.  0.100
  libavfilter     3. 68.101 /  3. 68.101
  libswscale      2.  3.100 /  2.  3.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  3.100 / 52.  3.100
[flv @ 0x257aec0] max_analyze_duration 5000000 reached at 5014000 microseconds
[flv @ 0x257aec0] Could not find codec parameters for stream 0 (Video: none): unspecified size
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, flv, from 'audioStream_0.4772734013386071.flv':
  Metadata:
    creationdate    : Thu May 30 10:44:55
    description     : Recorded using WebcamRecording example.
  Duration: 00:10:20.02, start: 0.000000, bitrate: 12 kb/s
    Stream #0:0: Video: none, 1k tbr, 1k tbn, 1k tbc
    Stream #0:1: Audio: nellymoser, 11025 Hz, mono, flt
Output #0, mp3, to 'foo.mp3':
  Metadata:
    creationdate    : Thu May 30 10:44:55
    description     : Recorded using WebcamRecording example.
    TSSE            : Lavf55.7.100
    Stream #0:0: Audio: mp3 (libmp3lame), 22050 Hz, mono, fltp
Stream mapping:
  Stream #0:1 -> #0:0 (nellymoser -> libmp3lame)
Press [q] to stop, [?] for help
size=    1251kB time=00:10:20.08 bitrate=  16.5kbits/s
video:0kB audio:1251kB subtitle:0 global headers:0kB muxing overhead 0.023194%