[Broadcaster] Send PLI fails sometimes

elixir-webrtc / apps

Example apps built on top of Elixir WebRTC

Apache License 2.0

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[Broadcaster] Send PLI fails sometimes #61

Open sgfn opened 1 month ago

mickel8 commented 1 month ago

Sometimes, browser doesn't start immediately sending all layers. Instead, it has to probe the connection. This means:

we cannot send PLi request before receiving the first packet for given layer as some SSRC
viewer has to wait additional time until browser starts sending h layer

Two things are actionable:

start sending whatever layer we have and then upgrade when better layer appears
why browser sometimes need to probe the connection and some other time it does not

mickel8 commented 1 month ago

why browser sometimes need to probe the connection and some other time it does not

This might have something to do with the frequency of TWCC repors we are sending. From video-dev slack:

It's very sensitive to the timing derived from TWCC packets. If you make a mistake in how you generate those or if you send them too slow I can see why it would sometimes behave like that

https://video-dev.slack.com/archives/C9PQ6FWH3/p1727878788799169?thread_ts=1727873414.829029&cid=C9PQ6FWH3