RE: [AVT] RTP streaming and adaptation to AVC of an SVC temporalscalable bitstream - Packet loss

[<Ye-Kui.Wang at nokia.com>]

Hi Colin, 

Thanks for your clarification. But according to the following sentence
copied from Daniele's email, 

"... then the SVCtoAVC adapter doesn't know whether this loss has to be
signaled to the receiver, i.e. whether it must insert a sequence number
gap in the outcoming RTP stream...", 

the SVCtoAVC adapter uses a different RTP sequence number value space
for the outcoming RTP steam than the incoming RTP stream. Is this what a
translator can do? It is not clear how the SVCtoAVC adapter handles the
CC, SSRC and CSRC fields and RTCP traffic, though. 

BR, YK

>-----Original Message-----
>From: ext Colin Perkins [mailto:csp at csperkins.org] 
>Sent: Saturday, August 18, 2007 9:07 PM
>To: Wang Ye-Kui (Nokia-NRC/Tampere)
>Cc: daniele at bsoft.info; avt at ietf.org
>Subject: Re: [AVT] RTP streaming and adaptation to AVC of an 
>SVC temporalscalable bitstream - Packet loss
>
>On 18 Aug 2007, at 18:36, <Ye-Kui.Wang at nokia.com> wrote:
>> In your example the SVCtoAVC adapter is an RTP mixer, which 
>terminates 
>> the RTP session between the sender and itself and restarts 
>another RTP 
>> session between itself and the receiver.
>> Therefore the RTP sequence number needs to be updated for the base 
>> layer packets anyway.
>
>If the SVCtoAVC adapter is a transcoder from an SVC stream to 
>an AVC stream, it will be an RTP translator, not an RTP mixer. 
>Neither an RTP translator or a RTP mixer terminate the RTP 
>session. RFC 3550 and draft-ietf-avt-topologies-06.txt discuss 
>this in more detail.
>
>--
>Colin Perkins
>http://csperkins.org/
>
>
>

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