Thank you, Eric.

By "video cancellation", I mean when the network bandwidth is very
small, we may send audio only and cancel the video. Does helix player
provide such a mechanism?
Or you always send video, even bandwidth is not enough?

--Laser

Eric Hyche wrote:
>Laser,
>
>I have heard the terms "stream thinning" used in different
>ways in different contexts. I'm not familiar with
>the term "video cancellation".
>
>In helix, when we say "stream thinning", we mean this:
>most of our video codecs have *as least* two rules associated with
>them: one for keyframes and one for non-keyframes.
>When the network delivery bandwidth drops below the level
>needed for non-keyframes, we drop into keyframe-only
>mode and send only keyframe packets. So in order to
>do this, the client sends an RTSP SET PARAMETER
>messages to the server and in that message Subscribes
>or Unsubscribes to the non-keyframe rule. This is
>what we mean by "stream thinnning".
>
>However, the same general principle applies for multi-rate
>streams with substreams that are encoded at completely
>different bitrates. But we usually refer to this
>as "stream switching" rather than "thinning".
>
>Eric
>
>==============================================
>Eric Hyche (ehyche at real.com)
>Embedded Player and Technologies
>RealNetworks, Inc. 
>
>
>  
>>-----Original Message-----
>>From: protocol-dev-bounces at helixcommunity.org 
>>[mailto:protocol-dev-bounces at helixcommunity.org] On Behalf Of 
>>laser9107 at 163.com
>>Sent: Wednesday, November 09, 2005 5:16 AM
>>To: protocol-dev at helixcommunity.org
>>Subject: [Protocol-dev] stream thinning and video cancellation
>>
>>Hello,
>>
>>Is there anyone know how Helix player and server handle 
>>stream thinning
>>and video cancellation?
>>What is the corresponding RTSP command?
>>
>>Thanks a lot!
>>
>>--laser
>>
>>
>>_______________________________________________
>>Protocol-dev mailing list
>>Protocol-dev at helixcommunity.org
>>http://lists.helixcommunity.org/mailman/listinfo/protocol-dev
>>
>>    
>
>
>
>