[Spice-devel] Video buffering

[John A. Sullivan III]

On Sat, 2011-06-18 at 21:26 +0200, Attila Sukosd wrote:
> Hi John,
> 
> Did you check the guest cpu usage while playing back youtube?
> 
> We have noticed that the bad video playback performance with flash was
> due to it using up all of the guest CPU, and of course it does not
> improve a lot by giving the VM more cores either... (ok this was on a
> 12 core AMD, where the cpu speed isn't as high per core as for other
> cpus)
> 
> Switching to HTML5 playback on youtube gave about the same video
> performance as playing it with VLC, and we could play back 720p over a
> 15mbit DSL line with an acceptable overall performance.
<snip>

It doesn't seem to be.  Here are some stats and examples:

http://www.youtube.com/watch?v=vb8njeKBfqw&feature=related
8-15% Flash 8-32% HTML5
http://www.youtube.com/watch?v=6eM8bXW3fhU&playnext=1&list=PL3CB56EAD33DEBAA6
5-18% Flash  9-32% HTML5
http://www.youtube.com/watch?v=tH-EVMUCsZc&feature=related
4-20% Flash  10-41% HTML5

As soon as something covers the video, we are able to take advantage of
SPICE's not writing hidden space and the audio picks right up.  As soon
as the video is exposed, it starts sputtering again.  Thanks - John

> 
> On Sat, Jun 18, 2011 at 8:17 PM, John A. Sullivan III
> <jsullivan at opensourcedevel.com> wrote:
> > Hello, all.  We spent some time testing audio and video performance with
> > SPICE today with mixed results.  Talking heads and some movement were
> > reasonably acceptable.  However we tried some music and ballet videos to
> > get lots of movement and the results were unusable - Rite of Spring was
> > more like Frozen Ice of Winter.  These were not full screen - simple
> > YouTube type video using an cable Internet connection - several Mbps
> > download, a couple upload.
> >
> > We are thus thinking of pursuing our plans to wrap SPICE inside X2Go so
> > we can use the new mimebox facility and offer users the choice of either
> > the streaming SPICE video approach or the more Citrix like download and
> > play locally approach.
> >
> > I'm guessing the problem is buffering.  If the pipe isn't big enough, it
> > just isn't going to get through in a usable way - stuttering and
> > starting all over the place.  Are there any plans to build some sort of
> > buffering into SPICE when it detects a video stream?
> >
> > I'm sure many are thinking likewise but we are looking at video as not
> > just a technology shift but a huge long term cultural shift almost as
> > large as the printing press so we see any VDI solution which does not
> > address video despite the huge technical hurdles as inadequate.
> >
> > We have already been told by some schools that they could not use our
> > X2Go VDI model because of their need for video.  Likewise, adoption has
> > been delayed by some large PR / Communications companies because of a
> > lack of video support.  As we look at consumerization of VDI for
> > potential service to lower income users, video is a potential show
> > stopper.
> >
> > Enough of teaching Grandma to suck eggs but this is why we are so
> > enthusiastic about SPICE - at least it has a fighting chance with video.
> > So we look forward to integrating with X2Go and would love to know if
> > there is a plan (or even an existing way) to implement buffering in
> > SPICE.  Thanks - John
> >
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