摄像头自拍影像的压缩

在win下面用摄像头自拍了一段录像，时间不长，但尺寸很大，是因为没有压缩的缘故，到Linux里面用file命令查看一下：

# file self.avi
self.avi: RIFF (little-endian) data, AVI, 640 x 480, ~15 fps, video:

用mplayer无法播放，主要错误信息如下：
Opening video decoder: [raw] RAW Uncompressed Video
VDec: vo config request - 640 x 480 (preferred colorspace: BGR 24-bit)
Could not find matching colorspace - retrying with -vf scale...
Opening video filter: [scale]
The selected video_out device is incompatible with this codec.
Try appending the scale filter to your filter list,
e.g. -vf spp,scale instead of -vf spp.
VDecoder init failed :(

到网上查了一下，用mencoder如此压缩：

# mencoder self.avi  -of lavf -o self.wmv -lavcopts vcodec=mpeg4 -ovc lavc -lavfopts i_certify_that_my_video_stream_does_not_use_b_frames -nosound

把2G的文件压缩成为16M，播放效果完美。