User-agent: Mozilla Thunderbird 1.0 (Windows/20041206)
Andreas Wittenstein wrote:
Paul,
Here's a simplification: Loop through the movie's video tracks' sample
descriptions, look at the data format, and decide whether any of them
warrant using 16-bit precision for RGB, for example by calling
'QTGetPixelFormatDepthForImageDescription()'.
Hi Andreas,
Yes, that will help determining the depth I need (maybe - since the
documentation for that function doesn't even mention 64-bit depths) once
I know the PixelFormat of the QuickTime media track I am trying to render.
But, it still doesn't help me determine what PixelFormat the track
itself needs.
Let me rephrase this again -
Given a Movie track, I need to determine what its PixelFormat is. In
other words, if the track contains 24-bit or 32-bit RGB data, I would
expect to get a PixelFormat of 32 (suitable for passing on to
QTNewGWorld). But, if the track is encoded with a 10-bit RGB codec for
example, I would expect to get k64ARGBPixelFormat or k48RGBPixelFormat
or something similar, so I know I need a *64-bit* GWorld to render the
movie into.
Perhaps if I knew how to get get the codec used for the track, I could
open the codec and ask what is preferred depth is. But I'm not sure what
functions to use to do that (get/open the codec needed to decompress the
track). Since I am using GetMoviePict() to render the movie, this is all
taken care of for me currently.
I suppose you need to loop through the movie's video tracks' sample
descriptions, look at the data format, and decide whether any of them
warrant using 16-bit precision for RGB, for example by looking up a
suitable image decompressor component for the format, and asking the
codec what precision to use for the track, which the codec returns in
the 'preferredOffscreenPixelSize' field of the
'CodecDecompressParams' argument to the 'Preflight()' selector.
--
Paul Miller | email@hidden | www.fxtech.com | Got Tivo?
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