[theora] png2theora.c + QImage
giles at thaumas.net
Wed Apr 18 09:01:34 PDT 2012
On 12-04-17 7:15 PM, Gustav González wrote:
> The point where I am stuck starts at this comment:
> // LOOK HERE (line 313)
This file is only 304 lines long.
> And here is the issue: QImage supports RGB images, so my first task is
> to transform
> the content of the QImage variable from RGB to YUV.
You did see there's already (more accurate) code to do this in
png2theora.c? See rgb_to_yuv in
https://svn.xiph.org/trunk/theora/examples/png2theora.c if you don't
have the latest version.
In particular, decimation isn't the best way to do chroma subsampling. :)
> As you already noticed it, I have to deal with a conflict of types. I
> was trying to cast the yuv variable from
> "uint8_t" to "unsigned char" and vice versa with no luck. The ogv file
> exported is always corrupted.
I didn't try compiling your code, but those types should be equivalent
under Qt. Perhaps the corruption is coming from the elsewhere in the
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