ffmpeg -i 1-1.flv -vcodec copy -acodec libfaac -ab 64k -f mp4 1-1.mp4
FFmpeg version SVN-r22846, Copyright (c) 2000-2010 the FFmpeg developers
  built on Apr 24 2010 14:05:24 with gcc 4.4.3
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --enable-static --enable-shared --cc=x86_64-pc-linux-gnu-gcc --disable-debug --disable-network --enable-libmp3lame --enable-libvorbis --enable-libx264 --enable-libxvid --enable-libfaac --enable-nonfree --disable-indev=v4l --disable-indev=oss --disable-indev=jack --disable-outdev=oss --enable-x11grab --enable-pthreads --enable-libfaad --disable-vdpau --disable-altivec --enable-gpl --enable-version3 --enable-postproc --enable-avfilter --enable-avfilter-lavf --disable-stripping --enable-hardcoded-tables --disable-doc
  libavutil     50.14. 0 / 50.14. 0
  libavcodec    52.66. 0 / 52.66. 0
  libavformat   52.61. 0 / 52.61. 0
  libavdevice   52. 2. 0 / 52. 2. 0
  libavfilter    1.19. 0 /  1.19. 0
  libswscale     0.10. 0 /  0.10. 0
  libpostproc   51. 2. 0 / 51. 2. 0
[flv @ 0x2484420]Estimating duration from bitrate, this may be inaccurate

Seems stream 0 codec frame rate differs from container frame rate: 1000.00 (1000/1) -> 12.00 (12/1)
Input #0, flv, from '1-1.flv':
  Metadata:
    creator         : hiei at popgo. m_908051880_id. Tudou@China
    metadatacreator : Tudou.Com
    hasKeyframes    : true
    hasVideo        : true
    hasAudio        : true
    hasMetadata     : true
    canSeekToEnd    : false
    duration        : 1390
    datasize        : 50828389
    videosize       : 38742811
    videocodecid    : 2
    width           : 320
    height          : 240
    framerate       : 12
    videodatarate   : 217
    audiosize       : 11806022
    audiocodecid    : 2
    audiosamplerate : 22000
    audiosamplesize : 16
    stereo          : true
    audiodatarate   : 63
    filesize        : 50830561
    lasttimestamp   : 1390
    lastkeyframetimestamp: 1377
    lastkeyframelocation: 50397274
  Duration: 00:23:10.02, start: 0.000000, bitrate: 229 kb/s
    Stream #0.0: Video: flv, yuv420p, 320x240, 221 kb/s, 12 tbr, 1k tbn, 1k tbc
    Stream #0.1: Audio: mp3, 22050 Hz, 2 channels, s16, 8 kb/s
[mp4 @ 0x2487a10]track 0: could not find tag, codec not currently supported in container
Output #0, mp4, to '1-1.mp4':
  Metadata:
    encoder         : Lavf52.61.0
    Stream #0.0: Video: flv, yuv420p, 320x240, q=2-31, 221 kb/s, 90k tbn, 1k tbc
    Stream #0.1: Audio: aac, 22050 Hz, 2 channels, s16, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Could not write header for output file #0 (incorrect codec parameters ?)