Thanks for the explanation ilia.
I'm curious too here that if it's legal for player to not respect the
image size when calling vlVaGetImage. If player already know the size of
image is 100x100, then why should it still call vlVaGetImage with
width/height=600?
I mean when VA-API player calls to create image and create surface, it
should behave itself, or will be considered a player bug. If player
calls something out of range, even the driver have the size
clipped(driver trying to fix player bug), but player still won't get
expected stuff, since the requested size have been clipped by driver.
Does this make sense?
Regards,
Boyuan
On 2018-10-09 02:10 PM, Ilia Mirkin wrote:
On Tue, Oct 9, 2018 at 1:59 PM Boyuan Zhang <boyzh...@amd.com> wrote:
Hi ilia,
I saw the function
u_box_clip_2d(https://cgit.freedesktop.org/mesa/mesa/tree/src/gallium/auxiliary/util/u_box.h#n74).
But I still don't quite understand why we need to do this? Or say, what
will happen if we don't do this box clipping here? Can you provide more
information about this please?
Sure. Let's say you have:
1000x1000 video surface
500x500 image
Then you call
vlVaGetImage(surface, x=600, y=600, width=600, height=600, image)
Ideally you would retrieve the 400x400 "valid" area (from 600x600 at
the surface) and stick it into the image starting at 0,0.
Then let's say you have
1000x1000 video surface
100x100 image
Then you call
vlVaGetImage(surface, x=600, y=600, width=600, height=600, image)
Ideally the image would be filled with a 100x100 square from the
surface starting at 600x600 and ending at 700x700.
I haven't deeply dived into the VA docs. Perhaps some or all of these
are illegal. In which case the x/y/w/h need to be checked and errors
returned.
Cheers,
-ilia
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