[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: IESG WG Review: IP over DVB (ipdvb) - Synchronised delivery of IP packets



Gorry Fairhurst wrote:

I believe you're asing for more detai of the synchronised delivery service...
Yes !!


To ensure we speak of the same thing the current requirements id (page 12) says:

             "The standard PES Packet as defined in table 2-18 of [ISO-
              MPEG] can also be used as a container for data packets. The
two values for the stream_id are "private_stream_1" and "private_stream_2". The private_stream_2 permits the use of
              the short PES header with limited overhead. This makes it
              attractive for publicly accessible multicast distribution
              services. The private_stream_1 makes available the scrambling
              control and the timing and clock reference features of the
              PES layer. The PES_data_packet_header_length will be used in
              this context to insert stuffing bytes. This is an important
              aspect since the payload can be aligned to 32-bit word
              boundaries. "
Ah ! I understood it was part of description of data-streaming !
but not a req itself. because PES packets may not be available in any
system using MPEG-2 ?


At the moment the proposed charter says we should consider this need, and assess the impact on the design of the encapsulation procdure.
OK : it must be looked, which doesn't mean it will be a requirement
for the encapsulation method.


Well, I maybe I missed some importants points, but if this feature is
important/needed/whatever, why is it not in the requirement draft ?


Correct, we need text, are you offering text?
Sorry, no:-(
I don't really grab the importance of such sync, neither I'm really
sure of its deepest implications. I don't see any use-case either

Does anyone else have text we can use to update the requirements draft with use-cases for this type of service?
Yep, it would be very helpfull understanding the real goal.

Regards.
Alain.
--
Alain RITOUX
Tel +33-1-39-30-92-32
Fax +33-1-39-30-92-11
visit our web http://www.6wind.com