[MPlayer-dev-eng] DxVA in MPlayer

[Laurent]

On Tue, Nov 23, 2010 at 4:17 PM, Reimar Döffinger
<Reimar.Doeffinger at gmx.de> wrote:
> On Tue, Nov 23, 2010 at 03:17:48PM -0500, Laurent wrote:

[...]

>> * 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.

I wander if VLC does not try to drop things, as it plays the video
within the original duration, while MPC-HT does not.

>>   Playback is not smooth, but not worse that MPC.
>>   It decodes all frames, with ~30-40% CPU.
>
> Could you describe "not smooth" more precisely? Does the file possibly
> have extreme bitrate spikes (which would mean it's also not-smooth
> always at the same places)? Or does it look like some issue with
> the video output method, or memory bandwidth, any hints?

The file indeed has some bitrate spikes (>20Mbps, dixit VLC). Though,
the issue is all over the video. It is rather a bit slow and jerky.
As playing the video in a smaller window makes it smooth, I would say
that the issue is on the rendering side, rather than on the decoding
one.

>
>> * VLC without DxVA does not play smooth (worse than with DxVA) and
>> uses 60% of the CPU.
>
> How many cores is that (real and virtual (HT))? Otherwise those
> values don't say anything really...

1 real core, with HT.
Having HT makes the numbers difficult to interpret (on top of
approximative measurements)...

For software decoding, I tried without HT, and got a slightly better
result, but the system becomes completely unresponsive.

> And I assume that is not using ffmpeg-mt?

Using the original VLC build, so I don't know if it uses -mt or not.

> I'm not going to ask you to try MPlayer ;-), even though I'd be curious,

It plays slooow (no worse than VLC, I think), ~45% CPU, with 1 core
highly used...


-- Laurent