The non-primary SSRC being RTX, for example. Normally a default stream
wouldn't be created from RTX packets, but there is a window of time
where packets can be received before the video engine has receive
parameters/payload type mappings, so it creates one anyway.
Then in AddRecvStream, normally the default stream would be destroyed
before creating a new one, but this only happens for sp.first_ssrc().
Resulting in the error "Receive stream with SSRC 'X' already exists".
Fixed by simply iterating over all SSRCs.
Bug: webrtc:13171
Change-Id: Iaf4e4a3ceafddee3d9b2d1e24af68be56f9695de
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/231633
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Commit-Queue: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#34971}
b9b0890541