FFmpeg version UNKNOWN, Copyright (c) 2000-2010 the FFmpeg developers
  built on Nov  9 2010 12:08:03 with gcc 4.2.1 (Apple Inc. build 5664)
  configuration: --prefix=/Users/worth/OtherApps/ffmpeg/ffmpeg/../local/i386 --enable-static --enable-shared --enable-gpl --enable-version3 --enable-libmp3lame --enable-pthreads --enable-libvorbis --enable-libx264 --enable-libxvid --enable-libspeex --enable-libopencore_amrwb --enable-libopencore_amrnb --enable-libvpx --enable-memalign-hack --disable-debug --disable-stripping --arch=x86_32
  libavutil     50.33. 0 / 50.33. 0
  libavcore      0.12. 0 /  0.12. 0
  libavcodec    52.94. 3 / 52.94. 3
  libavformat   52.84. 0 / 52.84. 0
  libavdevice   52. 2. 2 / 52. 2. 2
  libavfilter    1.59. 0 /  1.59. 0
  libswscale     0.12. 0 /  0.12. 0

Seems stream 1 codec frame rate differs from container frame rate: 12000.00 (12000/1) -> 6.00 (6/1)
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/willg/Movies/Miro/videoplayback-sparams=id,expire,ip,ipbits,itag,algorithm,burst,factor_fexp=90.25_id=d539458d95dc66ba.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isomavc1mp42
  Duration: 00:03:10.83, start: 0.000000, bitrate: 474 kb/s
    Stream #0.0(und): Audio: aac, 44100 Hz, stereo, s16, 123 kb/s
    Stream #0.1(und): Video: h264, yuv420p, 480x360 [PAR 1:1 DAR 4:3], 349 kb/s, 6 fps, 6 tbr, 6k tbn, 12k tbc
At least one output file must be specified
