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[AVT] MPEG2-TS preamble drafts
Hi
I have tried to compare the two competing ID's on MPEG2-TS preamble. Not being an expert in this area I anyway try to get an understanding
As I see it draft-xia-avt-mpeg2ts-preamble-00.txt is a simple version of draft-begen-avt-rtp-mpeg2ts-preamble-03.txt as the former does not need a specification of a new preamble format (for simplicity I call the drafts XIA and BEGEN)
The benefit XIA is that the endpoints (that understands RFC4588) does not need to be upgraded to understand a new preamble format, I cannot put any weight on this possible benefit.
The benefit with XIA compared to BEGEN comes with some drawbacks
1) Increased transmission overhead : BEGEN compresses the preamble info into one packet while XIA needs to transmit each packet that contains the preamble. This naturally means that the overhead increases. Does anybody have some figures as regards to how much this overhead increases ?.
2) Vulnerability to packetloss: XIA transmits the packets with preamble in several RFC4588 packets, which means that if one of these packets is lost the whole preamble is rendered useless. BEGEN compresses the preamble and can can possibly use this "compression gain" to transmit two identical preamble packets to cope with lossy environments.
In addition, if I was to come up with a solution to the preamble problem I would first consider the XIA alternative then the more elaborate BEGEN alternative. I am curious to know if the authors of BEGEN originally considered the alterantive outlined in XIA and if so what the motivation was to go for the current proposal.
Unfortunately I cannot say do this or that but I hope that my questions will help to advance this in a direction that is satisfactory for all.
/Ingemar
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INGEMAR JOHANSSON M.Sc.
Senior Research Engineer
Ericsson AB
Multimedia Technologies
Labratoriegränd 11
971 28, Luleå, Sweden
Phone +46-1071 43042
SMS/MMS +46-73 078 3289
ingemar.s.johansson at ericsson.com
www.ericsson.com
Visit http://labs.ericsson.com !
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