[MPlayer-DOCS] documenting lavdopts debug=0x4000

[Jeff Clagg]

Well, there are probably MANY things that could be added to the
documentation of lavdopts, but currently the easiest way to decipher the
meaning of the output of "lavdopts debug=0x4000" is a combination of
rtfs and lavdopts debug=0x4008. However, once we open this can of worms,
the lavdopts section of the man page might become extremely long.

Nevertheless, I'm going to suggest that we add explanations in the man
page of what each block tint/color actually means. One of my questions
is, should we stick to the old vertical listing style, which takes up a
heck of a lot of space, or just list them in sentence form?

While you argue that, here's my (hopefully correct and complete) list of
what all the colors mean:

Red: intra
Purple: 4x4 intra (H.264)
Green: forward-predicted
Blue: backward-predicted
Cyan: bidirectionally predicted
Orange: direct
Black and white (untinted): skip or direct-skip

Other things: lines are drawn across macroblocks to indicate partitions
in inter mb's (H.264) or the use of interlacing.

Also, I don't understand the colorspace used here so I'm not sure what
color to report for the following block types:
GMC (mpeg4 asp); PCM (H.264).
I'm pretty sure intra 8x8 blocks (H.264) are colored red, but not quite
positive.

Other cans of worms: if we document these, why not also document all the
output from debug=8 as well? Now you see how things start getting long,
especially with vertical listing. And clearly even much of the output of
debug=1 isn't always obvious, and some of it is codec-specific, some of
it is broken afaict,...