YUV software decode path stride fixes.

media/base/video_frame.cc

 // Copyright (c) 2012 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 "media/base/video_frame.h"
 
 #include "base/logging.h"
 #include "base/string_piece.h"
 #include "media/base/limits.h"
 #include "media/base/video_util.h"
@@ skipping 106 matching lines @@
   // Check that |alignment| is a power of 2.
   DCHECK((alignment + (alignment - 1)) == (alignment | (alignment - 1)));
   return ((value + (alignment - 1)) & ~(alignment-1));
 }
 
 static const int kFrameSizeAlignment = 16;
 // Allows faster SIMD YUV convert. Also, FFmpeg overreads/-writes occasionally.
 static const int kFramePadBytes = 15;
 
 void VideoFrame::AllocateRGB(size_t bytes_per_pixel) {
+  coded_size_.set_width(RoundUp(coded_size_.width(), 4));

[sheu, 2012/11/16 03:03:45]

This is kinda hacky.  I'm doing this basically because I don't want to have to
touch glStorePixeli(GL_UNPACK_ALIGNMENT), as if the coded size can be
arbitrarily aligned, then we have to set the unpack alignment to 1 when we do
the texture upload.

GL_EXT_unpack_subimage still gets bit by the unpack alignment.

   // Round up to align at least at a 16-byte boundary for each row.
   // This is sufficient for MMX and SSE2 reads (movq/movdqa).
   size_t bytes_per_row = RoundUp(coded_size_.width(),
                                  kFrameSizeAlignment) * bytes_per_pixel;
   size_t aligned_height = RoundUp(coded_size_.height(), kFrameSizeAlignment);
   strides_[VideoFrame::kRGBPlane] = bytes_per_row;
 #if !defined(OS_ANDROID)
   // TODO(dalecurtis): use DataAligned or so, so this #ifdef hackery
   // doesn't need to be repeated in every single user of aligned data.
   data_[VideoFrame::kRGBPlane] = reinterpret_cast<uint8*>(
       av_malloc(bytes_per_row * aligned_height + kFramePadBytes));
 #else
   data_[VideoFrame::kRGBPlane] = new uint8_t[bytes_per_row * aligned_height];
 #endif
   DCHECK(!(reinterpret_cast<intptr_t>(data_[VideoFrame::kRGBPlane]) & 7));
   COMPILE_ASSERT(0 == VideoFrame::kRGBPlane, RGB_data_must_be_index_0);
 }
 
 void VideoFrame::AllocateYUV() {
   DCHECK(format_ == VideoFrame::YV12 || format_ == VideoFrame::YV16);
-  // Align Y rows at least at 16 byte boundaries.  The stride for both
-  // YV12 and YV16 is 1/2 of the stride of Y.  For YV12, every row of bytes for
-  // U and V applies to two rows of Y (one byte of UV for 4 bytes of Y), so in
-  // the case of YV12 the strides are identical for the same width surface, but
-  // the number of bytes allocated for YV12 is 1/2 the amount for U & V as
-  // YV16. We also round the height of the surface allocated to be an even
-  // number to avoid any potential of faulting by code that attempts to access
-  // the Y values of the final row, but assumes that the last row of U & V
-  // applies to a full two rows of Y.
+  coded_size_.set_width(RoundUp(coded_size_.width(), 4));
+  // Align Y rows at least at 32 byte boundaries, so the stride for both YV12
+  // and YV16 at 1/2 of the stride of Y is aligned to 16. For YV12, every row of
+  // bytes for U and V applies to two rows of Y (one byte of UV for 4 bytes of
+  // Y), so in the case of YV12 the strides are identical for the same width
+  // surface, but the number of bytes allocated for YV12 is 1/2 the amount for
+  // U & V as YV16. We also round the height of the surface allocated to be an
+  // even number to avoid any potential of faulting by code that attempts to
+  // access the Y values of the final row, but assumes that the last row of U &
+  // V applies to a full two rows of Y.
   size_t y_stride = RoundUp(row_bytes(VideoFrame::kYPlane),
-                            kFrameSizeAlignment);
-  size_t uv_stride = RoundUp(row_bytes(VideoFrame::kUPlane),
-                             kFrameSizeAlignment);
+                            kFrameSizeAlignment * 2);
+  // We keep the UV stride (and height below) proportional to the Y stride
+  // (and height), since we will be assuming an identical scale factor for
+  // stride (and height) for the Y and UV planes.
+  size_t uv_stride = y_stride / 2;
   // The *2 here is because some formats (e.g. h264) allow interlaced coding,
   // and then the size needs to be a multiple of two macroblocks (vertically).
   // See libavcodec/utils.c:avcodec_align_dimensions2().
   size_t y_height = RoundUp(coded_size_.height(), kFrameSizeAlignment * 2);
   size_t uv_height = format_ == VideoFrame::YV12 ? y_height / 2 : y_height;
   size_t y_bytes = y_height * y_stride;
   size_t uv_bytes = uv_height * uv_stride;
 
 #if !defined(OS_ANDROID)
   // TODO(dalecurtis): use DataAligned or so, so this #ifdef hackery
@@ skipping 148 matching lines @@
       break;
     for(int row = 0; row < rows(plane); row++) {
       base::MD5Update(context, base::StringPiece(
           reinterpret_cast<char*>(data(plane) + stride(plane) * row),
           row_bytes(plane)));
     }
   }
 }
 
 }  // namespace media