rtspsrc/rtpbin: Doesn't sync A/V if the server does not provide RTCP
The A/V synchronization only happens in rtpbin
when it receives an RTCP SR from rtpjitterbuffer
. In case of RTSP this could already happen once the caps are received with clock-base
/ npt-start
, and the first packet is received to know the local arrival times. The clock-base
is the RTP timestamp of each stream that corresponds to npt-start
.
If the server never sends an RTCP SR then A/V sync is never fixed up, and even if the server sends an RTCP SR it would be much later than necessary.
This can probably be solved by adding a new variant of the sync
signal to rtpjitterbuffer
that provides clock-base
and npt-start
among other things and has rtpbin
handle this as a special-case in gst_rtp_bin_associate()
.