RE: [AVT] Update (-09) of Timed Tex draft (WAS: RE:Commentsondraft-ietf-avt-rtp-3gpp-timed-text-08.txt)

["Jose Rey" <Jose.Rey at panasonic.de>]

Colin,

[cut agreed]
> 
> > Note that sending a sample description together with every 
> text sample 
> > (or set of samples) may result in a situation where the same sample 
> > description is present in the receiver buffer many times, but with 
> > different timestamp values.  This is a desing choice to 
> ensure correct 
> > reception of sample descriptions and may cause moderate overhead.
> 
> I'm not sure this part's appropriate, since it assumes a 
> particular receiver buffer implementation strategy.
> 

I am assuming that only the basic functionality is implemented: opening RTP packets, reading out units, giving them a TS as the rules describe and storing them in the receiver buffer in TS order.  I intended to be as general as possible.  The last sentence may lead to misunderstanding.  Instead of that one, maybe describing an easy way to avoid this situation is more helpful:  

"Note that sending a sample description together with every text sample (or set of samples) may result in a situation where the same sample description is present in the receiver buffer many times, but with different timestamp values.  This can be avoided by maintaining a list of currently stored sample descriptions (i.e., their SIDX values) and checking this before writing in the buffer."



José


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