[Spice-devel] [PATCH 0/11] Add GStreamer and VP8 support

[Fabio Fantoni]

Il 21/05/2015 10:34, Fabio Fantoni ha scritto:
> Il 13/05/2015 22:20, Francois Gouget ha scritto:
>> This is a followup on Jeremy White's concept patch to use GStreamer:
>> http://www.spinics.net/lists/spice-devel/msg10030.html
>>
>> There is still a lot of work ahead but this patches series has all the 
>> infrastructure so we're sending it out to verify that it looks ok.
>>
>> First, with this patch series:
>>  1. You can use the SpiceVideoCodecs option in the xorg.conf file (or
>>     $XSPICE_VIDEO_CODECS) to set your video encoder and codec 
>>     preferences. The default is still the builtin MJPEG encoder.
>>
>>  2. You can do the same from QEmu by setting the video-codecs option.
>>
>>  3. Clients can expose new display capabilities to advertise that 
>>     they support either or both of the MJPEG and VP8 codecs. The new 
>>     server will automatically pick a codec they support based on the 
>>     above preference list. Older clients that don't advertise these new 
>>     capabilities will automatically get an MJPEG stream. So old and new 
>>     clients and servers should all be compatible.
>>
>>  4. The GTK and and HTML5 clients have been updated to support both 
>>     MJPEG and VP8.
>>
>>  5. Using GStreamer as the video encoder should work well for either 
>>     codecs as long as the stream does not hit your network connection's 
>>     bandwidth limit. Essentially this means it should be ok on LANs and 
>>     fast WiFi networks. This should even work with multiple clients.
>>
>>
>> There's one known issue in the framework: if the Spice server and 
>> clients have no codec in common, red_display_create_stream() will set 
>> video_encoder to NULL and that's not handled well. Currently this should 
>> really not happen as all clients support MJPEG and we have the builtin 
>> MJPEG encoder as a fallback. The root of the issue is that the 
>> red_display_create_stream() callers assume it will never fail. But I 
>> don't know how to change that yet.
>>
>>
>> The GStreamer backend still has a number of limitations:
>>  1. It's still based on GStreamer 0.10. I don't think moving to 1.0 
>>     will be a problem, if anything it should help (famous last words).
>>     For instance support for dynamically changing the bitrate appears to 
>>     be better in 1.0.
>>
>>  2. It still does not have any rate control but should work fine as long 
>>     as the bandwidth is sufficient. The issue with rate control is that, 
>>     at least in 0.10, GStreamer encoders don't like bitrate changes, 
>>     need some time after each change to actually match the new bitrate, 
>>     still tend to exceed it from time to time, and sometimes just won't 
>>     get anywhere near it. Part of these issues are likely to be bugs in 
>>     the current implementation and it should be possible to work around 
>>     most others.
>>
>>
>> Feedback would be greatly appreciated.
>>
>>
>> Cheers,
>>
> Thanks for improving spice, I tried your patches, I applied the
> spice-gtk, spice-protocol and I updated the git submodule to use right
> spice-protocol but make of spice-common/common generate a new enum.h and
> override the spice-protocol patch failing the spice-gtk build with vp8
> codec undefined.
> Seems that also a spice-common patch (at least in spice.proto) is needed
> but missed in the patch serie posted.
>
>

Some days ago I tested spice server and client updated and compatibility
with older of both seems ok.
Today I finally tested with video-codecs=gstreamer:vp8.
The video image often freezes for a moment (or probably until next imput
event or something).
qemu log have only some of this as particular:
Spice-Warning **: gstreamer_encoder.c:189:construct_pipeline: GStreamer
error: nessun elemento «appsrc»

You need full logs of spice server and/or spice with debug enabled?

If you need other informations/tests tell me and I'll post them.

Thanks for any reply and sorry for my bad english.
Thanks for any reply.

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