Re: [AVT] Some comments to subsection 8.1.1 in draft-ietf-avt-rtp-svc-08

[Colin Perkins <csp at csperkins.org>]

On 27 Mar 2008, at 21:39, <Ye-Kui.Wang at nokia.com> wrote:
...
> Here are some comments to subsection 8.1.1 in draft-ietf-avt-rtp- 
> svc-08,
> titled "The Classical RTP Decoding Order Recovery Mode". Basically I
> don't understand many details of the process described in the draft -
> for those I could guess I have made some suggestions below on how to
> improve the description.
>
> 1. In the following copied text, NTP timestamps of NAL units or
> operation point representations are mentioned. However, NAL units are
> not directly assoicated with NTP timestamps, which are only directly
> assoicated with RTCP SRs. The NTP timestamp for each NAL unit must be
> defined.

The RTCP SR packets define the mapping between the two timelines,  
allowing you to directly derive the NTP timestamps from the RTP  
timestamps in each session. This is the standard RFC 3550 semantics:  
nothing specific to this format needs to be defined.

-- 
Colin Perkins
http://csperkins.org/


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