AVTP CVF: ensure transmission time constraints (and other fixes)
When CVF payloader fragments an H.264 NAL that is to big to be sent in a single network packet, it currently keeps all fragments with the same PTS/DTS as the original one. While that works now, !800 (merged) introduces a more strict timing for packets transmission, so CVF payloader has to properly account for that.
While that is the main patch in this MR, it also has patches that fixes avtpcvfpay
behaviour regarding segments and seek events - all those are exposed by !800 (merged). So, basically, this MR is about making avtpcvfpay
work properly after !800 (merged) is merged.