Provide a Chrome-owned buffer to FFmpeg for video decoding, instead of

media/base/video_frame.cc

Index: media/base/video_frame.cc
===================================================================
--- media/base/video_frame.cc	(revision 139175)
+++ media/base/video_frame.cc	(working copy)
@@ -133,6 +133,44 @@
   strides_[VideoFrame::kVPlane] = uv_stride;
 }
 
+extern "C" {

[Ami GONE FROM CHROMIUM, 2012/05/26 22:52:34]

this should not be necessary

+#include <stdlib.h>

[Ami GONE FROM CHROMIUM, 2012/05/26 22:52:34]

this belongs at the top of the file

+}
+
+int VideoFrame::AllocateAlignedWithStrides(int strides[], int aligned_h)

[Ami GONE FROM CHROMIUM, 2012/05/26 22:52:34]

Welcome to C++!  We've got bools!

+{
+  if (format_ == RGB32) {
+    strides_[VideoFrame::kRGBPlane] = strides[0];
+    uint8_t *data;

[Ami GONE FROM CHROMIUM, 2012/05/26 22:52:34]

unnecessary; just use data_[VideoFrame::kRGBPlane] in the memalign call and make
things clearer.

+    if (posix_memalign((void **) &data, 32, strides[0] * aligned_h)) {

[Ami GONE FROM CHROMIUM, 2012/05/26 22:52:34]

32 is magic here and elsewhere.  Name-constant (enum) it?

[Ami GONE FROM CHROMIUM, 2012/05/26 22:52:34]

Does this even compile on windows?

[DaleCurtis, 2012/05/29 17:33:19]

I don't think this works on other platforms; for reference see all the memalign
business in av_malloc (mem.c) for different platforms. We even force
"hacked-memalign" on OSX.

Instead of backing this with uint8 above, we can just use the DecoderBuffer
class I'm introducing here:

http://codereview.chromium.org/10447035/

Then you don't need to worry about alignment, etc.

+      return -1;
+    }
+    data_[VideoFrame::kRGBPlane] = data;
+  } else if (format_ == VideoFrame::YV12 || format_ == VideoFrame::YV16) {

[Ami GONE FROM CHROMIUM, 2012/05/26 22:52:34]

Other than the memalign's this function is a dup of AllocateYUV / AllocateRGB
above.  Hopefully you can drop one of the copies (and assume always-aligned in
the non-NativeTexture case).

+    size_t y_height = aligned_h;
+    DCHECK(aligned_h >= rows(VideoFrame::kYPlane));
+    size_t uv_height = format_ == YV12 ? y_height >> 1 : y_height;
+    size_t y_bytes = y_height * strides[0];
+    size_t uv_bytes = uv_height * strides[1];
+    uint8_t *data;
+
+    if (posix_memalign((void **) &data, 32, y_bytes + (uv_bytes * 2) + kFramePadBytes)) {

[Ami GONE FROM CHROMIUM, 2012/05/26 22:52:34]

80-col limit, here and elsewhere

+      return -1;
+    }
+
+    data_[VideoFrame::kYPlane] = data;
+    data_[VideoFrame::kUPlane] = data + y_bytes;
+    data_[VideoFrame::kVPlane] = data + y_bytes + uv_bytes;
+    strides_[VideoFrame::kYPlane] = strides[0];
+    strides_[VideoFrame::kUPlane] = strides[1];
+    strides_[VideoFrame::kVPlane] = strides[1];
+  } else {
+    return -1;
+  }
+  is_aligned_alloc_ = 1;
+  return 0;
+}
+
 VideoFrame::VideoFrame(VideoFrame::Format format,
                        size_t width,
                        size_t height,
@@ -141,6 +179,7 @@
     : format_(format),
       width_(width),
       height_(height),
+      is_aligned_alloc_(0),
       texture_id_(0),
       texture_target_(0),
       timestamp_(timestamp),
@@ -158,7 +197,13 @@
   // In multi-plane allocations, only a single block of memory is allocated
   // on the heap, and other |data| pointers point inside the same, single block
   // so just delete index 0.
-  delete[] data_[0];
+  if (data_[0]) {
+    if (is_aligned_alloc_) {
+      free(data_[0]);
+    } else {
+      delete[] data_[0];
+    }
+  }
 }
 
 bool VideoFrame::IsValidPlane(size_t plane) const {