Add 8 pixels of padding around each rectangle under VP9.

remoting/codec/video_encoder_vpx.cc

Index: remoting/codec/video_encoder_vpx.cc
diff --git a/remoting/codec/video_encoder_vpx.cc b/remoting/codec/video_encoder_vpx.cc
index d92d5b336e1fdbcdb2b6b341ef9a9b7158e64543..317032cd03969228ec155f6895bf568099303581 100644
--- a/remoting/codec/video_encoder_vpx.cc
+++ b/remoting/codec/video_encoder_vpx.cc
@@ -373,14 +373,18 @@ void VideoEncoderVpx::PrepareImage(const webrtc::DesktopFrame& frame,
   }
 
   // Align the region to macroblocks, to avoid encoding artefacts.
+  // If VP9 is in use then we also pad the rectangles before aligning them, to
+  // avoid edge artefacts.
   // This also ensures that all rectangles have even-aligned top-left, which
   // is required for ConvertRGBToYUVWithRect() to work.
   std::vector<webrtc::DesktopRect> aligned_rects;
+  int padding = use_vp9_ ? 8 : 0;
   for (webrtc::DesktopRegion::Iterator r(frame.updated_region());
        !r.IsAtEnd(); r.Advance()) {
     const webrtc::DesktopRect& rect = r.rect();
     aligned_rects.push_back(AlignRect(webrtc::DesktopRect::MakeLTRB(

[Sergey Ulanov, 2015/01/13 19:19:42]

nit: you can just call updated_region->AddRect() here. There is no need to store
list of aligned rects in aligned_rects.

[Wez, 2015/01/13 19:29:05]

The idea was to allow AddRects() to do whatever smart optimizations it's capable
of.

In particular how does the current DesktopRegion handle reallocations for
internal structures if you build the region rectangle-by-rectangle?

-        rect.left(), rect.top(), rect.right(), rect.bottom())));
+        rect.left() - padding, rect.top() - padding, rect.right() + padding,
+        rect.bottom() + padding)));
   }
   DCHECK(!aligned_rects.empty());
   updated_region->Clear();