[Live-devel] RTP basics

[serkan bozkurt]

Hi Ross,

I have seen in the FAQ's part below ;

"STBs typically handle only MPEG Transport Streams,
not Elementary Streams or other data formats. (Because
MPEG Transport Streams contain their own timestamps,
they can be streamed via raw-UDP, with RTP timestamps
not being required.)"

ES's have presentation and decoding timestamps.
so why we need to use timestamps in the ES's and not
to use for MPEG 2 TS's.

Below is taken from rfc2250

"Each RTP packet will contain a timestamp derived from
the sender's 90KHz clock reference.  This clock is
synchronized to the system stream Program Clock
Reference (PCR) or System Clock Reference SCR)and
represents the target transmission time of the first
byte of the packet payload.  The RTP timestamp will
not be passed to the MPEG decoder.  This use of the
timestamp is somewhat different than normally is the
case in RTP, in that it is not considered to be the
media display or presentation timestamp. The primary
purposes of the RTP timestamp will be to estimate and
reduce any network-induced jitter and to synchronize
relative time drift between the transmitter and
receiver."

what do you think about this.


Best Regards....

 



		
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