patch by François Revol <revol at free dot fr>

- fix for multiple frames per chunk
- better probing
- better header parsing
- fixed some 4CCs
- use av_new_stream() (but still dealocates some of them with av_free())


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@790 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b