On Sun, 27 Jan 2008 07:56:31 -0800 Herman Robak wrote
On Sun, 27 Jan 2008 15:42:17 +0100, Terje J. Hanssen <[EMAIL PROTECTED]> wrote:
Are the above settings correct, or should something be changed and possibly
why?
What are really "W Ratio" and "H Ratio" vs "Aspect Ratio"?
What about color model to select, RGBA vs i.e YUVA or other?
YUVA.
According to the Cinelerra wiki (manual)
http://cvs.cinelerra.org/docs/wiki/doku.php?id=english_manual:cinelerra_cv_en_4#video_attributes
YUVA-8888
This allocates an alpha channel to the 8 bit YUV colormodel for
transparency. When using compressed footage, YUV colormodels are usually
faster than RGB colormodels. They also destroy fewer colors than RGB
colormodels. If footage stored as JPEG or MPEG is processed many times
in RGB, the colors will fade whereas they will not fade if processed in YUV.
RGB-Float
This allocates a 32 bit float for the R, G, and B channels and no alpha.
This is used for high dynamic range processing with no transparency.
Years of working with high dynamic range footage have shown floating
point RGB to be the best format for high dynamic range. RGB float does
not destroy information when used with YUV source footage and also
supports brightness above 100%. Be aware that some effects, like
Histogram, still clip above 100% when in floating point.
Some effects, like fade, work around the need for alpha channels while
other effects, like chromakey, require an alpha channel to do anything,
so it is a good idea to try the effect without alpha channels to see if
it works before settling on an alpha channel and slowing it down.
What is really "high dynamic range processing" as mentioned above?
----------------
Terje J. Hanssen
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