[MPlayer-dev-eng] DxVA in MPlayer

[Laurent]

Hi,

On Sat, Nov 20, 2010 at 7:37 AM, Georgi Petrov <gogothebee at gmail.com> wrote:

[...]

>
>> Um, in that case the GPU and CPU memory are likely to be shared,
>> and there shouldn't be much if any performance issue with
>> choosing the "readback" method.
>
> This sounds logical. However, Laurent told me that using VLC
> (readback) results is a slow frame rate and poor decoding (may be only
> on his hardware), while MPC-HC is okay. Laurent, which h/w did you use
> to perform the comparison?

I used the GMA500/atom h/w.
IIRC, 1080p trailers (transformers, for instance) were playing
smoothly on XP/DxVA1/MPC-HT and Linux/VAAPI/MPlayer.
Regarding Win7 and DxVA2, I performed new tests (using native resolution):
* Desktop compositing makes DxVA decoding (or rather rendering) deadly
slow, so has been disabled for tests.
* MPC-HT does not play smoothly, but decodes all frames with ~10% CPU.
* VLC performed better than in my previous tests, thanks to
compositing being disabled.
  Note that VLC has a decoding bug with Intel decoders, but that is
not really relevant ATM.
  Playback is not smooth, but not worse that MPC.
  It decodes all frames, with ~30-40% CPU.
* VLC without DxVA does not play smooth (worse than with DxVA) and
uses 60% of the CPU.

Those numbers are very approximative, but give an idea.
With DxVA, the bottleneck does not seem to be the CPU.
Also, when displaying in a lower resolution with mpc-ht, the clip gets
smooth (with DxVA).

-- Laurent