PSA: rtc_use_h264 is set to false when WebRTC is built with MSVC
mbon...@webrtc.org
Hi,
Later today, once I have landed https://webrtc-review.googlesource.com/c/src/+/116982, the GN argument rtc_use_h264 will be defaulted to false when Microsoft Visual C++ is used to compile WebRTC (and GN will complain if it is forced to true).
Rationale:
WebRTC depends on Chromium's build configuration for FFmpeg. Starting from release 64, Chromium has moved to build only with clang and the Chromium build configuration for FFmpeg no longer supports MSVC (since this commit last year).
WebRTC was left with 3 choices:
Keep using the last version of Chromium's //third_party/ffmpeg that had MSVC support.
This is what we did up to this point. This approach is non-optimal from a security perspective and overall not sustainable in the long term.
Maintain MSVC support ourselves: fix MSVC build errors whenever FFmpeg is rolled into //third_party/ffmpeg.
This is a lot of work (that we were taking for granted from Chromium's side) and does not appear viable at this time.
If someone wants to take over this task we are happy to approve patches. See these instructions.
Drop H264 support for MSVC by disabling ffmpeg.
Alternative 3 is what we chose to do, hence this PSA.
