[FFmpeg-devel] [PATCH v4 1/5] libavutil: VAAPI infrastructure
nfxjfg at googlemail.com
Sun Jan 24 14:12:41 CET 2016
On Sun, 24 Jan 2016 13:58:59 +0100
Timo Rothenpieler <timo at rothenpieler.org> wrote:
> >> + void *address;
> >> + // On current Intel drivers, derive gives you memory which is very slow
> >> + // to read (uncached?). It can be better for write-only cases, but for
> >> + // now play it safe and never use derive.
> > Still subject to debate when we introduce a "GPU memcpy".
> > I think someone on this list once even posted a patch to add such a
> > memcpy, but it didn't get in yet.
> Related article from Intel:
> It contains a ready-to-use copy-function, which just has to be converted
> from intrinsics to yasm.
> And propably also needs a reversed counterpart, as it's designed to copy
> from uswc memory to normal system memory, while ffmpeg also needs to
> copy data into such uswc buffers.
Yes, though apparently we can get by without this additional "cache"
suggested on this page.
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