[Spice-devel] spice

[Victor Toso]

Hi,

On Fri, Jun 24, 2022 at 01:57:01PM +0800, yipeng at nfs-hlj.com wrote:
> Hi,Victor!
> Thank you for your prompt reply. 
> I have a hardware device. Because its display is decoded by
> hardware and only supports H264 mode data stream, it does not
> support other modes. I want to use it to use the spice
> protocol. I have been learning about spice recently to see if
> spice can be run on this hardware device.

I understand you have h264 hw decoded. Your VM is remote or
running in the same machine? Your VM is Windows or Linux?

The hardware decoding to h264 is not hard. The hardware encoding
in h264 is harder. Might be better nowadays but I haven't tested
and for sure the code in spice-server needs tweaks for hardware
encoding.

Cheers,
Victor

> From: Victor Toso
> Date: 2022-06-23 19:16
> To: yipeng at nfs-hlj.com
> CC: spice-devel
> Subject: Re: spice
> Hi,
>  
> On Thu, Jun 23, 2022 at 02:15:23PM +0800, yipeng at nfs-hlj.com wrote:
> > Hi,Victor Toso!
> > I am learning spice code recently. I have some doubts about
> > spice display channel. I hope to get your reply.
>  
> You got it. I'm cc'ing spice-devel list which is the best place
> to ask for help related to Spice.
>  
> > 1. How does spice distinguish between video transmission and
> > picture transmission.
>  
> If the server is configured for streaming [0], it'll decide to
> start a video encoding based on how many updates it is getting
> from the Guest. We had a demo about it ages ago:
>  
>     https://www.youtube.com/watch?v=VUQYs72hrbM
>  
> > 2. in the process of video transmission, is it the number of
> > frames of all videos or the changing part of the transmitted
> > video.
>  
> Not sure I understand the question. The streaming will happen
> based on the amount of updates in a specific region of the
> Display. Let's say that you are playing a 720x360 video in a 4K
> display, only that region of the video is being updating too much
> and will be converted to a video stream. If you had two 720x360
> videos playing, that's where the options all/filter would change
> the behavior, I think. With one, you would get two video streams,
> with the other it'd combine them in both.
>  
> I'm talking from memory, so I might be wrong with some details.
>  
> Note that with most recent Desktop environments like GNOME or
> windows 10, there is a lot of 3D happening which is full screen,
> that means it is interesting to stream the whole desktop.
>  
> > 3. whether the transmission display can be configured to H264
> > mode.
>  
> It can, but it is software encoding. The default is the mjpeg
> encoder. H264, vp8/vp9 is using gstreamer and the code would most
> definitely need tweaks and tests to be considered for
> production... This is a heads up.
>  
> What is your use case?
>  
> [0] If using libvirt, that means setting <streaming mode=all> (or
> filter). See host video encoding at:
>     https://www.spice-space.org/spice-user-manual.html
>  
> Cheers,
> Victor
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