VideoLayerImpl: subtract 1 from visible size when calculating tex stretch.

cc/layers/video_layer_impl.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/video_layer_impl.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 166 matching lines @@
 
   Occlusion occlusion_in_video_space =
       draw_properties()
           .occlusion_in_content_space.GetOcclusionWithGivenDrawTransform(
               transform);
   gfx::Rect visible_quad_rect =
       occlusion_in_video_space.GetUnoccludedContentRect(quad_rect);
   if (visible_quad_rect.IsEmpty())
     return;
 
-  // Pixels for macroblocked formats.
+  // Pixels for macroblocked formats. To prevent sampling outside the visible
+  // rect, stretch the video if needed.
+  gfx::Rect visible_sample_rect = frame_->visible_rect();
+  if (visible_rect.width() < coded_size.width() && visible_rect.width() > 1)
+    visible_sample_rect.set_width(visible_rect.width() - 1);
+  if (visible_rect.height() < coded_size.height() && visible_rect.height() > 1)
+    visible_sample_rect.set_height(visible_rect.height() - 1);
   const float tex_width_scale =
-      static_cast<float>(visible_rect.width()) / coded_size.width();
+      static_cast<float>(visible_sample_rect.width()) / coded_size.width();
   const float tex_height_scale =
-      static_cast<float>(visible_rect.height()) / coded_size.height();
+      static_cast<float>(visible_sample_rect.height()) / coded_size.height();
 
   switch (frame_resource_type_) {
     // TODO(danakj): Remove this, hide it in the hardware path.
     case VideoFrameExternalResources::SOFTWARE_RESOURCE: {
       DCHECK_EQ(frame_resources_.size(), 0u);
       DCHECK_EQ(software_resources_.size(), 1u);
       if (software_resources_.size() < 1u)
         break;
       bool premultiplied_alpha = true;
       gfx::PointF uv_top_left(0.f, 0.f);
@@ skipping 48 matching lines @@
                                   frame_->format(), media::VideoFrame::kAPlane,
                                   coded_size));
       }
 
       // Compute the UV sub-sampling factor based on the ratio between
       // |ya_tex_size| and |uv_tex_size|.
       float uv_subsampling_factor_x =
           static_cast<float>(ya_tex_size.width()) / uv_tex_size.width();
       float uv_subsampling_factor_y =
           static_cast<float>(ya_tex_size.height()) / uv_tex_size.height();
-      gfx::RectF ya_tex_coord_rect(visible_rect);
+      gfx::RectF ya_tex_coord_rect(visible_sample_rect);
       gfx::RectF uv_tex_coord_rect(
-          visible_rect.x() / uv_subsampling_factor_x,
-          visible_rect.y() / uv_subsampling_factor_y,
-          visible_rect.width() / uv_subsampling_factor_x,
-          visible_rect.height() / uv_subsampling_factor_y);
+          visible_sample_rect.x() / uv_subsampling_factor_x,
+          visible_sample_rect.y() / uv_subsampling_factor_y,
+          visible_sample_rect.width() / uv_subsampling_factor_x,
+          visible_sample_rect.height() / uv_subsampling_factor_y);
 
       YUVVideoDrawQuad* yuv_video_quad =
           render_pass->CreateAndAppendDrawQuad<YUVVideoDrawQuad>();
       yuv_video_quad->SetNew(
           shared_quad_state, quad_rect, opaque_rect, visible_quad_rect,
           ya_tex_coord_rect, uv_tex_coord_rect, ya_tex_size, uv_tex_size,
           frame_resources_[0].id, frame_resources_[1].id,
           frame_resources_[2].id,
           frame_resources_.size() > 3 ? frame_resources_[3].id : 0,
           color_space);
@@ skipping 125 matching lines @@
 void VideoLayerImpl::SetNeedsRedraw() {
   SetUpdateRect(gfx::UnionRects(update_rect(), gfx::Rect(bounds())));
   layer_tree_impl()->SetNeedsRedraw();
 }
 
 const char* VideoLayerImpl::LayerTypeAsString() const {
   return "cc::VideoLayerImpl";
 }
 
 }  // namespace cc