[Spice-devel] [spice-server v2 8/9] reds: add support to ranks for video codecs

[Francois Gouget]

On Tue, 13 Dec 2016, Victor Toso wrote:
[...]
> > Why do you need a rank?
> 
> To be able to select video-codecs based on both host and client
> preferences.

I guess that by client you mean the Spice client (spice-gtk).

Assuming that's desired, then what you need is a way for the Spice 
client to express preferences. Currently it cannot because all it sends 
to the server is the list of supported codecs as an unordered 
capabilities set. So you'll need to add some sort of message to send a 
preference list. That list can be in the same format as on the server, 
that is an ordered semi-colon separated list of encoder:codec pairs.

Then armed with both the server's and client's preferences you determine 
which encoder:codec to use.

So I see no need for a rank.


Then there's the issue of whether to pick an encoder:codec pair based on 
the server administrator's wants, or based on the user of the Spice 
client's wants.

Given that encoding is pretty resource intensive and performed on the 
server I consider that the server administrator's preferences should be 
given priority, hence the current scheme where we have a preference list 
on the server and simple capabilities for the client.


-- 
Francois Gouget <fgouget at codeweavers.com>