obs-webrtc: Add AV1 Support

[Sean-Der]

Description

This adds AV1 support to obs-webrtc

Motivation and Context

Users wish to use AV1

How Has This Been Tested?

Tested against Broadcast Box

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[Sean-Der]

Adding AV1 is done in this commit d639dda

Migrating the libdatachannel usage to C -> C++ is done in this commit 11a6348

Migration to C++ is a prerequisite for AV1 support.

[tytan652]

Those changes must be guarded behind #if version (e.g. 1.19.0 since it is not released), some distro will not use an alpha version to build OBS Studio.

[Sean-Der]

@tytan652 We use an alpha version of libdatachannel today. No stable release of libdatachannel exists that can be used with OBS.

I can ask for a stable release if packagers/distros want. Since libdatachannel isn't packaged anywhere I anticipate WebRTC will be disabled in most places :(

[tytan652]

Since libdatachannel isn't packaged anywhere I anticipate WebRTC will be disabled in most places :(

So I am off-topic: It was already available on the AUR (ArchLinux User Repo) with author of libdatachannel help since a while. So people that build obs-studio-git have bad build of the webrtc plugin and my dev machine too.
A PR to make CMake fail if the version is too low (if libdatachannel does things right and changed the version in CMake) might be needed as a fix.

Edit: I repeat this is off-topic.

[Conan-Kudo]

I can ask for a stable release if packagers/distros want. Since libdatachannel isn't packaged anywhere I anticipate WebRTC will be disabled in most places :(

Please get a released version in place for OBS (and packagers) to depend on.

[tytan652]

@Conan-Kudo, this is off-topic of the PR.
But maybe try to discuss libdatachannel author/maintainer directly about libdatachannel stabilization.

[Lain-B]

I'll just throw in one very final thing on that off-topic discussion here: there's no need to rush things. I'd agree with @Conan-Kudo and @tytan652. But don't push public packages to release alpha as stable, make sure it's fully stabilized. Let's just all have patience. 🙂

(Also it would be nice if there were version macros)

Glad to see more AV1 PRs.

[Sean-Der]

@Lain-B Good news! AV1 is now available in stable v0.19.0

Post v30.0 would it be ok to update the deps and enable AV1 for OBS?

[Sean-Der]

AV1 is now available in the libdatachannel that OBS uses. This PR is ready for review/merge.

[kimilpyoung]

Hi guys
When using the AV1 codec, frequent video freezing issues seem to occur due to keyframe problems.
After a keyframe arrives and the video playback resumes, the video plays normally for a while.
However, after a certain amount of time, the video stops and �Browser can no longer receive keyframes from OBS.

When setting the keyframe interval to 1 second, the video experiences frequent interruptions. The testing environment is 1920x1080 at 60fps with a bitrate of 6000 Kbps.

This happening on Windows, using an Intel 12900k, Geforce 4090.