commit 0145db40912babe3f74e00bed01df1a7b4502105
author Henrik Boström <hbos@webrtc.org> Wed Jul 26 12:01:59 2023
committer WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Jul 26 13:48:41 2023
tree b967b3ddce346b74d7f711d9b59b2d86f3a59f6c
parent 9130431b54fd18aa4857614c886aeeed1731fcf7

Recreate the stream when switching from standard to legacy API.

ReconfigureEncoder() is supposed to recreate the send stream when
switching between legacy and standard API paths to ensure that the
upper and lower layers agree on the number of streams that exist
(legacy = 3 encodings but 1 stream, standard = same as encodings).

This successfully happened when going from standard to legacy but due
to a bug in the condition this did not happen when going from legacy to
standard because `scalability_mode_used` is always false here (even
though the standard path does use a scalability mode).

As a consequence, SetRtpParameters()'s call to UpdateSendState()
resulted in a DCHECK-crash. In release builds we still avoid IOOB
because active_modules.size() < rtp_streams.size() but to avoid mistakes
like this happening again in the future, the DCHECK is promoted to a
CHECK.

The fix is to remove the scalability mode condition which didn't make
sense anyway - changing scalability mode does not require recreation but
recreation is necessary when number of streams change, whether or not
scalability mode changed.

TESTED = Using Simulcast Playground and switching back and forth
between standard and legacy and changing scalability modes and
confirming from stats, see https://crbug.com/1467455.

Bug: chromium:1467455
Change-Id: Ide29742972ba83f2e0a11f135ab9b39c39d4eb49
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/313280
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#40477}