[Magnus and Dave in discussion on SMPTE]
A. Is it acceptable to get the update a bit late? Using RTCP
can easily result in that the time code update arrives up to a
few seconds late. However if some latency is acceptable, the
RTCP bandwidth and the usage of the AVPF profile can ensure
that one maintain a limit on the latency to send the update.
I *think* so...
This is an important point, so further feedback on this is crucial.
I think the right answer to the question is "depends on the app", and
separates into two questions:
A. For the app, is associating the wrong SMPTE code with the RTP
stream for a few seconds a disaster?
B. For the app, how much advance notice does it have of an upcoming
SMPTE change?
Apps where A="yes" and B="very little if any" are probably not going
to be happy with the RTCP approach ... apps where A="no" will be
fine with the RTCP approach ... the final class of apps is "it depends".
An example of "B=little if any" is when the SMPTE is changing because
an operator is hitting buttons on a tape-deck controller, and is expecting
the RTP-controlled rack-mount to respond with 5 ms latency over a local
LAN in a reliable way.