RE: [AVT] Summary of 3GPP timed text draft

Hi John,

thanks for the comments. Please see below.

> -----Original Message-----
> From: avt-admin@ietf.org [mailto:avt-admin@ietf.org]On Behalf Of John
> Lazzaro
> Sent: Monday, July 07, 2003 9:56 PM
> To: avt@ietf.org
> Subject: Re: [AVT] Summary of 3GPP timed text draft
>
>
>
> >  "Jose Rey" <rey@panasonic.de> writes:
> >
> > The open issues/TODO list includes:
> >
> > - resilient transport: repetition, fragmentation,
> retransmission, FEC
> > (other?). It is our opinion that repetition should be
> included at the
> > very least.
>
> Is RTCP expected to be normally used with this payload format?

Not necessarily. Yes for unicast, but there's no plan to use RTCP
feedback in a first stage of the MBMS Service, that's why repetition is
important as a base mechanism.

cheers,

José

> If so,
> maybe the core idea behind the RTP MIDI resiliency -- a
> "recovery journal"
> in every packet coding the recent past, whose contents grow and shrink
> as the sender examines RTCP RR reports which indicate the highest
> sequence number the receiver has received -- could be the starting
> point of a timed text resiliency scheme.  For the default 5 second
> RTCP sending rate, and text that is not sent too frequently, one
> could imagine a recovery journal approach would be more efficient
> that simple repetition.  But you need RTCP to make it work ...
>
> --------------------------------------------------------------
> -----------
> John Lazzaro -- Research Specialist -- CS Division -- EECS --
> UC Berkeley
> lazzaro [at] cs [dot] berkeley [dot] edu
> www.cs.berkeley.edu/~lazzaro
> --------------------------------------------------------------
> -----------
>
> _______________________________________________
> Audio/Video Transport Working Group
> avt@ietf.org
> https://www1.ietf.org/mailman/listinfo/avt
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