The EncoderStreamFactory triggers different code paths depending on
`number_of_streams`: one for simulcast and one for non-simulcast.
The non-simulcast path is desired for both normal streams and SVC
streams.
The simulcast path gives sensible max bitrates for 4:2:1 scenarios, but
when encodings like {active,inactive,inactive} is specified in order to
do standard SVC, the max bps of the first encoding is so low that an
SVC stream will never send more than its first spatial layer (even when
scaleResolutionDownBy is 1).
Because of this, standard SVC is broken. This CL fixes this problem by
using the CreateDefaultVideoStreams() code path instead, which is the
same one that legacy SVC uses. With this fix, legacy and standard SVC
produce the same behavior regarding bitrate.
An added benefit of this is that numberOfSimulcastStreams == 1 in the
standard SVC path as well.
{active,inactive,inactive} tests are updated to verify the full
resolution is achieved after ramp-up. I've also confirmed that this
fixes the bug in Canary, see https://crbug.com/1428098#c2.
Bug: chromium:1428098, webrtc:15041, webrtc:15034
Change-Id: Ia1eb4ff59c4e2a56af833f7ac907a66bca8ea054
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/299147
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39697}
c99753ac8f