rtpmanager: improve performance in NACK/RTX handling
Submitted by Miguel París Díaz
I am providing several changes to improve NACK/RTX handling.
The general remarks are:
- Add GstRTPRetransmissionListRequest that allows send a list of seqnum to ask for NACKS. avoiding sending a lot of events on packet looses bursts.
- GstRtpRtxQueue: several changes to avoid unnecessary operations.
- Add "rtt" field in both GstRTPRetransmissionRequest and GstRTPRetransmissionListRequest that allows upstream elements like GstRtpRtxQueue to send retransmissions under the RTT.
Anyway, each commit has more detailed info.