[Spice-devel] xf86-video-qxl performance

[Marc-André Lureau]

Hi

----- Mensaje original -----
> Also, as a crazy idea, has anyone considered implementing a pure
> streaming video driver?  That is, what if we had a frame buffer
> driver,
> and then a thread that fired 29 times a second to drive a theora or
> vp8
> encoder, simply feeding the current frame at those intervals.

Even if doable, using theora or vp8 would result in poor visual quality
that isn't really acceptable for desktops.

Although there are some screencast video codecs (microsoft a developped
several over the years, unfortunately, there aren't very well known, and
I wonder how they differ from some kind of saved rdp stream)

However, I haven't look much at optimization, but I can imagine it
could be interesting to combine drawing operation more aggressively
perhaps based on a timer too (I don't think we do it, but I know that we
do some combining in some cases when the sending queue is full).
That could cost some host cpu though, but lower bandwidth...

There is certainly room for experimentation, improvements and tweaking!


> The advantage to that crazy proposal is that it would likely make the
> pure html5 client work 'perfectly'.  The obvious disadvantage is that
> it
> would consume a lot more cpu resources on the host, although it's not
> clear to me how substantial that would be.

In general video compression is substantially more intensive than
image compression. Long time ago, I ran some checks with vp8 (and webp)
with speed encoding params (low quality) and it was like ~x10-x20 slower
than jpeg-turbo iirc. Would be worth re-doing those tests, it's not
difficult. But I was discouraged to look further at that time.