MJPEG Tools Svn

Convert another utility/filter over to the new API and generalize to more
than 411 and 420 chroma formats.

Another utility converted over to the new YUV4MPEG2 API - chroma subsampling
generalized beyond 4:1:1 and 4:2:0

1) Added more chroma-information functions:

o y4m_chroma_parse_keyword()
o y4m_chroma_keyword()
o y4m_chroma_description()

2) Made use of those functions in appropriate places.

Accept the API extensions.

Rewrite to use the new YUV4MPEG2 API. The program shrank considerably in size
thanks to the new routines/accessor-functions available.

-v gives input stream info summary rather than 100 frame progress meter.

Rewrite to use the new YUV4MPEG2 API

Dammit --- I DID IT AGAIN: type "cvs commit yuv4mpeg.h yuv4mpeg.h" instead
of "cvs commit yuv4mpeg.h yuv4mpeg.c".

GOT IT RIGHT NOW.
Must investigate why smack to forehead failed.
Kicking self in butt in meantime.

(ps: Finally succeeded in committing code for y4m_chroma_ss_[xy]_ratio().)

o Remove sms's addition of y4m_get_chroma_ss().
o Actually commit the *code* for the y4m_chroma_ss_[xy]_ratio() functions.
o Smack myself in forehead twice (for good measure).

Note to those who read notes:

y4m_chroma_ss_[xy]_ratio() returns the scaling ratio "n:d" by which the
chroma planes are subsampled/scaled from full resolution. This means,
more or less, that any regions defined on a frame need to be aligned to
a multiple of "d" pixels --- since to a zeroth-order approximation, "d"
luma pixels correspond to "n" chroma pixels.

-matto

Add y4m_get_chroma_ss() function. Returns the subsampling factors (i.e. for
411 those are 4 and 1, for 422 those are 2 and 2, and so on). Useful for
programs that need to make sure counts are a proper multiple of the chroma
subsampling factor.