Bug 1996020 - use frame buffer pool in DesktopCaptureImpl::OnCaptureResult r=dbaker

Differential Revision: https://phabricator.services.mozilla.com/D270253

Author: mjfroman

dom/media/systemservices/video_engine/desktop_capture_impl.cc

@@ -273,7 +273,8 @@ DesktopCaptureImpl::DesktopCaptureImpl(const int32_t aId, const char* aUniqueId,
       mDeviceType(aType),
       mControlThread(mozilla::GetCurrentSerialEventTarget()),
       mNextFrameMinimumTime(Timestamp::Zero()),
-      mCallbacks("DesktopCaptureImpl::mCallbacks") {}
+      mCallbacks("DesktopCaptureImpl::mCallbacks"),
+      mBufferPool(false, 2) {}
 
 DesktopCaptureImpl::~DesktopCaptureImpl() {
   MOZ_ASSERT(!mCaptureThread);
@@ -399,6 +400,8 @@ int32_t DesktopCaptureImpl::StopCapture() {
     mRequestedCapability = mozilla::Nothing();
   }
 
+  mBufferPool.Release();
+
   if (mCaptureThread) {
     // CaptureThread shutdown.
     mCaptureThread->AsyncShutdown();
@@ -472,18 +475,24 @@ void DesktopCaptureImpl::OnCaptureResult(DesktopCapturer::Result aResult,
     return;
   }
 
-  int stride_y = width;
-  int stride_uv = (width + 1) / 2;
-
   // Setting absolute height (in case it was negative).
   // In Windows, the image starts bottom left, instead of top left.
   // Setting a negative source height, inverts the image (within LibYuv).
 
   mozilla::PerformanceRecorder<mozilla::CopyVideoStage> rec(
       "DesktopCaptureImpl::ConvertToI420"_ns, mTrackingId, width, abs(height));
-  // TODO(nisse): Use a pool?
-  webrtc::scoped_refptr<I420Buffer> buffer =
-      I420Buffer::Create(width, abs(height), stride_y, stride_uv, stride_uv);
+  // The more basic I420Buffer constructor defaults stride_y to width;
+  // and stride_u and stride_v as (width + 1) / 2, so we can use this
+  // call to CreateI420Buffer that takes only width and height.
+  webrtc::scoped_refptr<webrtc::I420Buffer> buffer =
+      mBufferPool.CreateI420Buffer(width, abs(height));
+  if (!buffer) {
+    RTC_LOG(LS_ERROR) << "Failed to allocate I420Buffer from pool.";
+    MOZ_ASSERT_UNREACHABLE(
+        "We might fail to allocate a buffer, but with this "
+        "being a recycling pool that shouldn't happen");
+    return;
+  }
 
   const int conversionResult = libyuv::ConvertToI420(
       videoFrame, videoFrameLength, buffer->MutableDataY(), buffer->StrideY(),

dom/media/systemservices/video_engine/desktop_capture_impl.h

@@ -24,6 +24,7 @@
 #include "api/sequence_checker.h"
 #include "api/video/video_frame.h"
 #include "api/video/video_sink_interface.h"
+#include "common_video/include/video_frame_buffer_pool.h"
 #include "modules/desktop_capture/desktop_capturer.h"
 #include "modules/video_capture/video_capture.h"
 #include "mozilla/DataMutex.h"
@@ -135,6 +136,8 @@ class DesktopCaptureImpl : public DesktopCapturer::Callback,
       mCallbacks;
   // Subscribers to this event will be notified when the capture has ended.
   mozilla::MediaEventProducer<void> mCaptureEndedEvent;
+
+  webrtc::VideoFrameBufferPool mBufferPool;
 };
 
 }  // namespace webrtc