How to recover paused video stream?


I am trying to use 3rd party webrtc client to connect Jitsi video bridge and I can get video streams from remote chrome jitsi client.

What I observed is that it seems received video stream contains multiple SSRCs (mixed streams from one port), and I want to implement filter to just render package with specific SSRC.
But the problem is that when switching SSRC, video got paused and PLI was sent to video bridge, but it seems video bridge ignored my PLI request and video still got paused.
I’m wondering is there specific request for PLI package for video bridge?

I think there are 2 SSRCS in PLI control frame , one is local SSRC(Video Receiver SSRC) in header, another one is remote SSRC(Video sender SSRC) in payload.
For remote SSRC, should I use SSRC specified in media description in XMPP message, or just use dynamic SSRC associated to video stream?