Implement rtpgccbwe

[ehfd]

Reference the issue numbers and reviewers Use # and @ to tag issues and reviewers.

Issue: #78

Explain relevant issues and how this pull request solves them A clear and concise description of the pull request. Ex. This pull request addresses issue # by [...]

Fixes #78

Describe the changes in code and its dependencies and justify that they work as intended after testing A clear and concise description of what you have changed. Please confirm that the pull request does not break this project by testing it in depth.

Translation of https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/blob/main/net/webrtc/src/webrtcsink/imp.rs for twcc and rtpgccbwe. Further analysis of the webrtcsink code is required.

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered other than this pull request, if applicable.

Additional context Add any other context or screenshots about the pull request here. Please describe whether you are willing to provide funding, as this will greatly accelerate your request.

• [x] I confirm that this pull request is relevant to the scope of this project. If you know that upstream projects are the cause of this problem, please file the pull request there.
• [x] I confirm that this pull request has been tested thoroughly and to the best of my knowledge that additional unintended problems do not arise.
• [x] I confirm that the style of the changed code conforms to the overall style of the project.
• [x] I confirm that I have read other open and closed pull requests and that duplicates do not exist.
• [x] I confirm that I have justified the need for this pull request and that the changes reflect the fix for the specified problem.
• [x] I confirm that no portion of this pull request contains credentials or other private information, and it is my own responsibility to protect my privacy.

[ehfd]

Current state: rtpgccbwe is implemented but doesn't work due to the lack of twcc. Need to implement twcc by translating https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/blob/main/net/webrtc/src/webrtcsink/imp.rs.

[ehfd]

twcc was implemented, but a few issues remain:

• Understand whether x-google-per-layer-pli=1 needs to be munged or not.
• Opus has a strange water splash-like high-pitch sound caused by no congestion management. Investigate useinbandfec=1.

Otherwise, the fix for video is beautiful even in very high bitrates. Nearly no stutter.

[ehfd]

Quality improved by adding FEC for audio and not using FEC for video (NACK/PLI/FIR is sufficient and FEC makes video inefficient).

Sustained stable bandwidth up to 30-40 mbps is achieved.