1453269 - Remove screen capture resolution hack from MediaEngineRemoteVideoSource.cpp

Status: NEW

(Core :: WebRTC: Audio/Video, enhancement, P3)

Description

[Andreas Pehrson [:pehrsons]]

In bug 1211656 we fixed constraints for screen sharing by hacking the desired resolution into a capability (essentially encoding the ideal and max constraint into one variable for each dimension) and handing it to the capture backend.

This hack later resulted in bug 1359662 and bug 1450954.

With bug 1388219 we support downscaling in the child process and would no longer need this hack. It's not optimal for perf to always capture at full resolution and pass such frames over IPC, but if that means we can leave the upstream capture backend unmodified it is still preferred IMO.

We'd need a way to figure out the captured screen's resolution ahead of selecting a capbility to be able to decide on the settings for a capture before resolving any capture requests.

Extra care needs to be taken for window captures where the size of the window may change dynamically while still fulfilling constraints.

[1] https://searchfox.org/mozilla-central/rev/6bfadf95b4a6aaa8bb3b2a166d6c3545983e179a/dom/media/webrtc/MediaEngineRemoteVideoSource.cpp#820-839
[2] https://searchfox.org/mozilla-central/rev/6bfadf95b4a6aaa8bb3b2a166d6c3545983e179a/dom/media/webrtc/MediaEngineRemoteVideoSource.cpp#490-501

Comment 1

[calonjunec]

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