[Pixman] [cairo] Planar YUV support

Siarhei Siamashka siarhei.siamashka at gmail.com
Fri Feb 25 05:00:13 PST 2011

On Tuesday 09 March 2010 18:09:57 Benjamin Otte wrote:
> Hey,
> Here's an update on my work on YUV planar support, also known as "what
> we got from the gstreamer-cairo hackfest". I've reworked my experimental
> code from back then to incorporate the things we agreed on. It is not
> complete yet, but only misses details. So if you're a maintainer of the
> libraries in question, now is a good time for a review and complaints or
> issues with the general design of the code.
> The code can be found in these 3 places:
>   http://cgit.freedesktop.org/~company/cairo/log?h=planar
>   http://cgit.freedesktop.org/~company/pixman/log?h=planar
>   http://cgit.freedesktop.org/~company/gst-plugins-cairo
> I constantly rebase and update it while I work on it, so that the final
> merge contains a proper set of patches.

Hi, what is the current status of this work? Is it still being developed, put 
on hold, or maybe even totally dead by now?

I'm cautiously interested in getting planar YUV format support added to
pixman/cairo for the purpose of implementing some kind of reasonably
well performing software fallback solution for html5 video in browsers
when hardware acceleration is either impossible or too difficult to use.
And this looks like a much smaller scale task than your work because:
1. Just read-only support for planar YUV format is enough
2. Image quality is less important than performance, so that the precise
filtering details or chroma siting can be just ignored
3. Probably just only SD color matrix (Rec.  601) would be enough for the start

The only missing thing in pixman API right now is the ability to wrap the
output of video decoder (3 buffers corresponding to the color planes) into
pixman_image_t for using it as source image in compositing operations.

Would it be possible to introduce this minor pixman API extension right now, 
possibly in time for pixman 0.22.0 release? And then continue your efforts,
which are targeted at implementing complete YUV support also suitable for high
quality video editing purposes (if I understand it correctly).

Best regards,
Siarhei Siamashka

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