What is the PLI in RTCP really mean?

[pei qian]

Hi :

I'm building a soft-MCU for video conference with webrtc. It works. 

I noticed the chrome (24m) send PLI with REMB parameters to me. I checked the RFC4585 and find out that mean "picture lost" but the video is fine.

how should I response to it ?

thanks!

[Mamadou]

This is just an indication and there is no RTP sequence number in such
packets.
For example, based on these indications your server can decide to
lower the bandwidth usage (lower bit rate, image down-scaling ...) or
strength the FEC protection length.
Another important RTCP packets are NACK and FIR:
- NACK will contains a list (sequence numbers) of all lost packets
- FIR to request sending full intra refresh frame
On the other side, just notice the fact that Chrome is sending tens of
PLI is not correct according to the standard as the RTCP bandwidth
should be something like 5% of the RTP.

[Venkatesh]

Hi:

I believe we opened up a bug for the "tens of PLI" being sent by the client here:

http://code.google.com/p/webrtc/issues/detail?id=1289

Venkatesh

--

[Venkatesh]

I meant this bug: http://code.google.com/p/webrtc/issues/detail?id=1288

Sorry about that.

Venkatesh

[pei qian]

Hi Mamadou:

As you said, I received many NACK with lost seq list. But it confuse me too, I don't know how to response.

as the "draft-ietf-rtcweb-rtp-usage-05" said. retransmit will cause some side-effects. so I'm working hard in the case testing chrome 24m 's response of my NACK.

Do you know the proper response of NACK ? 

Thanks.

[pei qian]

Thanks Venkatesh !

WEBRTC is great. I learnt much from it.