+ avcodec_get_pix_fmt
converts textual representation of pixel format into
the actual id. Complements avcodec_get_pix_fmt_name.
+ avpicture_layout
serializes given picture into a flat array.
Complements avpicture_fill.
* adding a new option -pix_fmt to the ffmpeg, in order to control
pixel format for the codecs that do support it, like rawvideo,
for example.
* reducing complexity of the rawvideo codec by splitting it in two
and making it more reliable via hooking up to the avpicture_layout.
Plus adding new FourCC as described here: http://www.fourcc.org
* A tiny fix for avienc.c that makes avih and video strf consistent
regarding codec FourCC.
Originally committed as revision 1842 to svn://svn.ffmpeg.org/ffmpeg/trunk
