tree d4c8cf211e245210a73181025375ef53c9872efa
parent 49ac6b758cc3c28be2fc13028a829f016b453d39
author Henrik Boström <hbos@webrtc.org> 1737555217 +0100
committer WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> 1737563245 -0800

Add unidirectional codec support ("offer to send" use case).

This CL implements allowing sendonly codecs in setCodecPreferences(),
i.e. this spec PR: https://github.com/w3c/webrtc-pc/pull/3018. It also
makes the setCodecPreferences() ignore level IDs in the filtering
algorithm (but not in the sCP method call) as per this spec PR:
https://github.com/w3c/webrtc-pc/pull/3023.

In short, before this CL, setCodecPreferences() threw an exception if a
codec was preferred that is not present in receiver codec capabilities.
After this CL, setCodecPreferences() allows you to prefer codecs that
are *either* in the sender capabilities *or* the receiver capabilities.
- This allows you to "offer to send", i.e. prefer sendonly codecs on a
  sendonly transceiver.
- The filtering on direction is handled by
  RtpTransceiver::filtered_codec_preferences() which is called during
  SDP offer/answer (sdp_offer_answer.cc).

Also as per spec changes, if this filtering results in not having any
codecs to offer or answer then this results in not having any codec
preferences as opposed to throwing an exception (old behavior).
- Two old peer_connection_media_unittest.cc tests are updated to
  reflect the API failing less.

This CL adds both unit tests (rtp_transceiver_unittest.cc) and full
stack integration tests (peer_connection_encodings_integrationtest.cc).
It also makes us pass the following Web Platform Tests in Chrome:
https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/web_tests/external/wpt/webrtc/protocol/h265-level-id.https.html

Bug: chromium:381407888
Change-Id: I98a5ad1acccb56db0538e4d47975b8a725102c33
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/374520
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Henrik Boström <hbos@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Evan Shrubsole <eshr@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#43788}