I heard that iptv uses udp multicast, so I thought that performance might be better if we use udp for video streaming. We can ignore missing and out of order frames. Does it make sense?
I understand that we need tcp channels for all others such as input and audio channels. 2016-02-02 23:03 GMT+09:00 Gerd Hoffmann <[email protected]>: > On Di, 2016-02-02 at 10:24 +0100, Christophe Fergeau wrote: > > Hey, > > > > On Tue, Feb 02, 2016 at 06:10:28PM +0900, Sunny Shin wrote: > > > I have a few questions about udp version of spice protocol. > > > > > > Is there a plan to support udp in spice protocol? > > > > > > If we support udp, what do we need to implement? > > > Is it enough to change tcp channels to udp ones? > > > > Maybe that would be enough, maybe more changes would be needed, I cannot > > exactly tell you. My main worries with UDP would be packet drops as > > there is nothing guaranteeing you that the packets you send will arrive > > at all to the other end of the connexion. > > That is exactly the problem. Packets may get dropped. Packets may also > arrive out-of-order. So using UDP is fine if loosing data is fine[1]. > > For spice this is largely not ok. Maybe for the audio channel, if you > are willing to accept sound dropouts in case of packet loss. Loosing > display channel messages will lead to rendering gliches due to missing > data and render tree inconsistencies. Not cool. Loosing input channel > messages may mess up the keyboard state such as keys being stuck due do > keyup messages being lost. That is even less funny. Webdav file > sharing corrupting your files? Have the backups ready! > > cheers, > Gerd > > [1] In theory one could implement some scheme to track packet > status, resend lost packets etc to fix this. In practice > the better answer to that is "use TCP" which does exactly > that. And keep in mind that the TCP algorithms in todays > OS kernels are the result of decades of network protocol > research. Coming up with an implementation which matches > TCP in performance certainly is not trivial. > >
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