H264SPS: Centralize computation of coded size and visible rect.

media/gpu/h264_decoder.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 <algorithm>
 #include <limits>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback_helpers.h"
 #include "base/macros.h"
 #include "base/numerics/safe_conversions.h"
+#include "base/optional.h"
 #include "base/stl_util.h"
 #include "media/gpu/h264_decoder.h"
 
 namespace media {
 
 H264Decoder::H264Accelerator::H264Accelerator() {}
 
 H264Decoder::H264Accelerator::~H264Accelerator() {}
 
 H264Decoder::H264Decoder(H264Accelerator* accelerator)
@@ skipping 1056 matching lines @@
   if (!sps)
     return false;
 
   *need_new_buffers = false;
 
   if (sps->frame_mbs_only_flag == 0) {
     DVLOG(1) << "frame_mbs_only_flag != 1 not supported";
     return false;
   }
 
-  // Calculate picture height/width in macroblocks and pixels
-  // (spec 7.4.2.1.1, 7.4.3).
-  int width_mb = sps->pic_width_in_mbs_minus1 + 1;
-  int height_mb = (2 - sps->frame_mbs_only_flag) *
-                  (sps->pic_height_in_map_units_minus1 + 1);
-
-  if (width_mb > std::numeric_limits<int>::max() / 16 ||
-      height_mb > std::numeric_limits<int>::max() / 16) {
-    DVLOG(1) << "Picture size is too big: width_mb=" << width_mb
-             << " height_mb=" << height_mb;
+  gfx::Size new_pic_size = sps->GetCodedSize().value_or(gfx::Size());
+  if (new_pic_size.IsEmpty()) {
+    DVLOG(1) << "Invalid picture size";
     return false;
   }
 
-  gfx::Size new_pic_size(16 * width_mb, 16 * height_mb);
-  if (new_pic_size.IsEmpty()) {
-    DVLOG(1) << "Invalid picture size: " << new_pic_size.ToString();
+  int width_mb = new_pic_size.width() / 16;
+  int height_mb = new_pic_size.height() / 16;
+
+  // Verify that the values are not too large before multiplying.
+  if (std::numeric_limits<int>::max() / width_mb < height_mb) {
+    DVLOG(1) << "Picture size is too big: " << new_pic_size.ToString();
     return false;
   }
 
-  if (!pic_size_.IsEmpty() && new_pic_size == pic_size_) {
+  if (new_pic_size == pic_size_) {
     // Already have surfaces and this SPS keeps the same resolution,
     // no need to request a new set.
     return true;
   }
 
   pic_size_ = new_pic_size;
   DVLOG(1) << "New picture size: " << pic_size_.ToString();
 
   int level = sps->level_idc;
   int max_dpb_mbs = LevelToMaxDpbMbs(level);
@@ skipping 317 matching lines @@
 
 gfx::Size H264Decoder::GetPicSize() const {
   return pic_size_;
 }
 
 size_t H264Decoder::GetRequiredNumOfPictures() const {
   return dpb_.max_num_pics() + kPicsInPipeline;
 }
 
 }  // namespace media