[Spice-devel] Information about video detection

[Yonit Halperin]

Hi,
On 07/01/2013 04:27 AM, Matilde Yanez wrote:
> Hello,
>
> I need some information about video detection, on VM.
> When I am on web pages, or documents, with images the VM seems to detect
> video and start the mjpeg_encoder process.
> Thus, the display is slows down.
>
What vm are you using? We encountered such behaviour with gnome-shell, 
due to high frequency updates of regions over the primary surface.
> With argument streaming-video=off, the CPU consomation goes up.
This is unexpected. On which guest scenarios?
> Increasing the value of "RED_STREAM_FRAMES_START_CONDITION", does not
> launch the video detection on these documents and keep fluidity on
> videos and documents
>
> How can i make difference between real video, and documents with images?
I'm afraid there is no simple answer for this
(1) Why does the driver send frequent updates? Does the rectangles that 
are being updated really change? Can it be prevented on the driver side?
(2) If the area that is being refreshed doesn't change much, we can 
apply a quick comparison of sampled regions of 2 successive "frames", 
and if most of the pixels stay the same, we won't consider those 
"frames" as part of a video stream. (for such scenarios we would also 
like to improve and employ the GLZ encoding, or change our caching 
mechanism, to be applied on slices of bitmaps)
>   On what part of the spice-server code can i make changes?
Code that is related to video streams is located in red_worker.c, in 
routines with "stream|upgrade" in their names.
>
> Thanks,
> Matilde.
>
Regards,
Yonit.
>
>
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