HD-Video Hardwar Acceleration?

Corbin Simpson mostawesomedude at gmail.com
Sat Aug 29 15:55:09 PDT 2009

I don't feel like digging through emails and writing point-by-point
replies, so I'm just going to do point-by-point talking-to-myself.

- The APIs for accelerating full decoding and not just colorspace
conversion and scaling (Xv) are:
-- XvBA
-- XvMC

Of those, only VDPAU is worth implementing. XvMC can be done in terms of
VDPAU if you're creative enough.

- OpenCL would be fine for video, but stupid and slow, just like
OpenGL-based video decoding.

- The current plan is to *not* add any more video decoding to any DDX,
but to do it in Gallium using a state tracker. Expand g3dvl to be a true
pipeline, let drivers fill in the pipeline with whatever they can
accelerate, and then expose VDPAU and XvMC to userspace. Of course, only
radeon (me, MrCooper) and nouveau (marcheu, ymanton) have actually
agreed that this is a good idea, but the intel devs will probably keep
maintaining their XvMC and VA-API implementation either way.

- It's not done because we've been working on other things. If it makes
you feel better, 3D support *is* required for this kind of work, since
we don't have documentation on the dedicated video decoders onboard most
GPUs, and we haven't reverse-engineered them, so we'll have to use 3D
shaders instead.

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