WebCodecs remote video encoders get timestamps in microseconds and no…

…t nanoseconds

rdar://123684436
https://bugs.webkit.org/show_bug.cgi?id=270159

Reviewed by Eric Carlson.

In WebRTC code path, we are getting a microsecond timestamp.
We were converting it to a MediaTime in LibWebRTCCodecs which was then converted back to
a nanosecond timestamp in LibWebRTCCodecsProxy.
A factor of 1000 was applied in LibWebRTCCodecs and handled correctly on LibWebRTCCodecsProxy.

The WebCodecs path is getting a MediaTime directly but without the 1000 factor.
This was causing the timestamps given to WebCodecs encoder to be in microseconds and not nanoseconds.
This can have an impact on encoders in some circumstances.

We fix this by using Seconds/MediaTime routines on WebProcess WebRTC side (this removes the 1000 factor),
and we update LibWebRTCCodecsProxy to do the same.

* Source/WebKit/GPUProcess/webrtc/LibWebRTCCodecsProxy.mm:
(WebKit::LibWebRTCCodecsProxy::encodeFrame):
* Source/WebKit/WebProcess/GPU/webrtc/LibWebRTCCodecs.cpp:
(WebKit::LibWebRTCCodecs::encodeFrame):

Canonical link: https://commits.webkit.org/275392@main

Source/WebKit/GPUProcess/webrtc/LibWebRTCCodecsProxy.mm

@@ -440,7 +440,7 @@ static bool validateEncoderConfiguration(VideoCodecType codecType, const String&
 
 #if !PLATFORM(MACCATALYST)
     encoder->encodingCallbacks.append(WTFMove(callback));
-    webrtc::encodeLocalEncoderFrame(encoder->webrtcEncoder, pixelBuffer.get(), sharedVideoFrame.time.toTimeScale(1000000).timeValue(), timeStamp, duration, toWebRTCVideoRotation(sharedVideoFrame.rotation), shouldEncodeAsKeyFrame);
+    webrtc::encodeLocalEncoderFrame(encoder->webrtcEncoder, pixelBuffer.get(), Seconds(sharedVideoFrame.time.toDouble()).nanoseconds(), timeStamp, duration, toWebRTCVideoRotation(sharedVideoFrame.rotation), shouldEncodeAsKeyFrame);
 #else
     callback(false);
 #endif

Source/WebKit/WebProcess/GPU/webrtc/LibWebRTCCodecs.cpp

@@ -693,7 +693,7 @@ template<typename Frame> int32_t LibWebRTCCodecs::encodeFrameInternal(Encoder& e
 
 int32_t LibWebRTCCodecs::encodeFrame(Encoder& encoder, const webrtc::VideoFrame& frame, bool shouldEncodeAsKeyFrame)
 {
-    return encodeFrameInternal(encoder, frame, shouldEncodeAsKeyFrame, toVideoRotation(frame.rotation()), MediaTime(frame.timestamp_us() * 1000, 1000000), frame.timestamp(), { }, [](auto) { });
+    return encodeFrameInternal(encoder, frame, shouldEncodeAsKeyFrame, toVideoRotation(frame.rotation()), MediaTime::createWithDouble(Seconds::fromMicroseconds(frame.timestamp_us()).value()), frame.timestamp(), { }, [](auto) { });
 }
 
 int32_t LibWebRTCCodecs::encodeFrame(Encoder& encoder, const WebCore::VideoFrame& frame, int64_t timestamp, std::optional<uint64_t> duration, bool shouldEncodeAsKeyFrame, Function<void(bool)>&& callback)