flv does not support that sample rate, choose from

# ffmpeg -y -ar 44100 -i in.avi out.flv
FFmpeg version SVN-r11087, Copyright (c) 2000-2007 Fabrice Bellard, et al.
  configuration: --enable-gpl --enable-pp --enable-libmp3lame
--enable-libfaad --enable-libfaac
  libavutil version: 49.5.0
  libavcodec version: 51.48.0
  libavformat version: 52.0.0
  built on Nov 24 2007 16:07:44, gcc: 4.1.3 20070929 (prerelease) (Ubuntu
4.1.2-16ubuntu2)
Input #0, avi, from 'in.avi':
  Duration: 01:57:10.8, start: 0.000000, bitrate: 834 kb/s
    Stream #0.0: Video: mpeg4, yuv420p, 544x304 [PAR 1:1 DAR 34:19], 23.98tb(r)
    Stream #0.1: Audio: mp3, 48000 Hz, stereo, 128 kb/s
Output #0, flv, to 'out.flv':
    Stream #0.0: Video: flv, yuv420p, 544x304 [PAR 1:1 DAR 34:19], q=2-31,
200 kb/s, 23.98 tb(c)
    Stream #0.1: Audio: libmp3lame, 48000 Hz, stereo, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
[libmp3lame @ 0x84d1e90]flv does not support that sample rate, choose from
(44100, 22050, 11025).
Could not write header for output file #0 (incorrect codec parameters ?)

这种错误一般是因为音频采样率没有选择好，应该按照提示改一下音频采样率，如(44100, 22050, 11025)