media: Add support for playback of VP8 Alpha video streams

media/filters/skcanvas_video_renderer.cc

Index: media/filters/skcanvas_video_renderer.cc
diff --git a/media/filters/skcanvas_video_renderer.cc b/media/filters/skcanvas_video_renderer.cc
index b478a731b58541d5f8cc7394e05e01c06e2edf2c..94395bfdb94950749dd7fbde109a08a1b991bd7a 100644
--- a/media/filters/skcanvas_video_renderer.cc
+++ b/media/filters/skcanvas_video_renderer.cc
@@ -21,6 +21,17 @@ static bool IsEitherYV12OrYV16OrNative(media::VideoFrame::Format format) {
       format == media::VideoFrame::NATIVE_TEXTURE;
 }
 
+static bool IsEitherYV12OrYV12AOrYV16(media::VideoFrame::Format format) {
+  return IsEitherYV12OrYV16(format) ||
+      format == media::VideoFrame::YV12A;
+}
+
+static bool IsEitherYV12OrYV12AOrYV16OrNative(
+    media::VideoFrame::Format format) {
+  return IsEitherYV12OrYV16OrNative(format) ||
+      format == media::VideoFrame::YV12A;
+}
+
 // CanFastPaint is a helper method to determine the conditions for fast
 // painting. The conditions are:
 // 1. No skew in canvas matrix.
@@ -70,7 +81,8 @@ static void FastPaint(
   const SkBitmap& bitmap = canvas->getDevice()->accessBitmap(true);
   media::YUVType yuv_type = media::YV16;
   int y_shift = 0;
-  if (video_frame->format() == media::VideoFrame::YV12) {
+  if (video_frame->format() == media::VideoFrame::YV12 ||
+      video_frame->format() == media::VideoFrame::YV12A) {
     yuv_type = media::YV12;
     y_shift = 1;
   }
@@ -170,9 +182,9 @@ static void FastPaint(
 static void ConvertVideoFrameToBitmap(
     const scoped_refptr<media::VideoFrame>& video_frame,
     SkBitmap* bitmap) {
-  DCHECK(IsEitherYV12OrYV16OrNative(video_frame->format()))
+  DCHECK(IsEitherYV12OrYV12AOrYV16OrNative(video_frame->format()))
       << video_frame->format();
-  if (IsEitherYV12OrYV16(video_frame->format())) {
+  if (IsEitherYV12OrYV12AOrYV16(video_frame->format())) {
     DCHECK_EQ(video_frame->stride(media::VideoFrame::kUPlane),
               video_frame->stride(media::VideoFrame::kVPlane));
   }
@@ -189,45 +201,75 @@ static void ConvertVideoFrameToBitmap(
   }
 
   bitmap->lockPixels();
-  if (IsEitherYV12OrYV16(video_frame->format())) {
-    media::YUVType yuv_type = media::YV16;
-    int y_shift = 0;
-    if (video_frame->format() == media::VideoFrame::YV12) {
-      yuv_type = media::YV12;
-      y_shift = 1;
-    }
 
+  size_t y_offset = 0;
+  size_t uv_offset = 0;
+  if (IsEitherYV12OrYV12AOrYV16(video_frame->format())) {
+    int y_shift = (video_frame->format() == media::VideoFrame::YV16) ? 0 : 1;
     // Use the "left" and "top" of the destination rect to locate the offset
     // in Y, U and V planes.
-    size_t y_offset = (video_frame->stride(media::VideoFrame::kYPlane) *
-                       video_frame->visible_rect().y()) +
-                      video_frame->visible_rect().x();
-
+    y_offset = (video_frame->stride(media::VideoFrame::kYPlane) *
+                video_frame->visible_rect().y()) +
+                video_frame->visible_rect().x();
     // For format YV12, there is one U, V value per 2x2 block.
     // For format YV16, there is one U, V value per 2x1 block.
-    size_t uv_offset = (video_frame->stride(media::VideoFrame::kUPlane) *
-                        (video_frame->visible_rect().y() >> y_shift)) +
-                       (video_frame->visible_rect().x() >> 1);
-    uint8* frame_clip_y =
-        video_frame->data(media::VideoFrame::kYPlane) + y_offset;
-    uint8* frame_clip_u =
-        video_frame->data(media::VideoFrame::kUPlane) + uv_offset;
-    uint8* frame_clip_v =
-        video_frame->data(media::VideoFrame::kVPlane) + uv_offset;
-
-    media::ConvertYUVToRGB32(frame_clip_y,
-                             frame_clip_u,
-                             frame_clip_v,
-                             static_cast<uint8*>(bitmap->getPixels()),
-                             video_frame->visible_rect().width(),
-                             video_frame->visible_rect().height(),
-                             video_frame->stride(media::VideoFrame::kYPlane),
-                             video_frame->stride(media::VideoFrame::kUPlane),
-                             bitmap->rowBytes(),
-                             yuv_type);
-  } else {
-    DCHECK_EQ(video_frame->format(), media::VideoFrame::NATIVE_TEXTURE);
-    video_frame->ReadPixelsFromNativeTexture(*bitmap);
+    uv_offset = (video_frame->stride(media::VideoFrame::kUPlane) *
+                (video_frame->visible_rect().y() >> y_shift)) +
+                (video_frame->visible_rect().x() >> 1);
+  }
+  switch (video_frame->format()) {
+    case media::VideoFrame::YV12:
+      media::ConvertYUVToRGB32(
+          video_frame->data(media::VideoFrame::kYPlane) + y_offset,
+          video_frame->data(media::VideoFrame::kUPlane) + uv_offset,
+          video_frame->data(media::VideoFrame::kVPlane) + uv_offset,
+          static_cast<uint8*>(bitmap->getPixels()),
+          video_frame->visible_rect().width(),
+          video_frame->visible_rect().height(),
+          video_frame->stride(media::VideoFrame::kYPlane),
+          video_frame->stride(media::VideoFrame::kUPlane),
+          bitmap->rowBytes(),
+          media::YV12);
+      break;
+
+    case media::VideoFrame::YV16:
+      media::ConvertYUVToRGB32(
+          video_frame->data(media::VideoFrame::kYPlane) + y_offset,
+          video_frame->data(media::VideoFrame::kUPlane) + uv_offset,
+          video_frame->data(media::VideoFrame::kVPlane) + uv_offset,
+          static_cast<uint8*>(bitmap->getPixels()),
+          video_frame->visible_rect().width(),
+          video_frame->visible_rect().height(),
+          video_frame->stride(media::VideoFrame::kYPlane),
+          video_frame->stride(media::VideoFrame::kUPlane),
+          bitmap->rowBytes(),
+          media::YV16);
+      break;
+
+    case media::VideoFrame::YV12A:
+      media::ConvertYUVAToARGB(
+          video_frame->data(media::VideoFrame::kYPlane) + y_offset,
+          video_frame->data(media::VideoFrame::kUPlane) + uv_offset,
+          video_frame->data(media::VideoFrame::kVPlane) + uv_offset,
+          video_frame->data(media::VideoFrame::kAPlane),
+          static_cast<uint8*>(bitmap->getPixels()),
+          video_frame->visible_rect().width(),
+          video_frame->visible_rect().height(),
+          video_frame->stride(media::VideoFrame::kYPlane),
+          video_frame->stride(media::VideoFrame::kUPlane),
+          video_frame->stride(media::VideoFrame::kAPlane),
+          bitmap->rowBytes(),
+          media::YV12);
+      break;
+
+    case media::VideoFrame::NATIVE_TEXTURE:
+      DCHECK_EQ(video_frame->format(), media::VideoFrame::NATIVE_TEXTURE);
+      video_frame->ReadPixelsFromNativeTexture(*bitmap);
+      break;
+
+    default:
+      NOTREACHED();
+      break;
   }
   bitmap->notifyPixelsChanged();
   bitmap->unlockPixels();
@@ -255,7 +297,8 @@ void SkCanvasVideoRenderer::Paint(media::VideoFrame* video_frame,
 
   // Paint black rectangle if there isn't a frame available or the
   // frame has an unexpected format.
-  if (!video_frame || !IsEitherYV12OrYV16OrNative(video_frame->format())) {
+  if (!video_frame ||
+      !IsEitherYV12OrYV12AOrYV16OrNative(video_frame->format())) {
     canvas->drawRect(dest, paint);
     return;
   }