Add VAVDA, the VAAPI Video Decode Accelerator for Intel CPUs.

content/common/gpu/media/h264_dpb.h

+// 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.
+//
+// This file contains an implementation of an H.264 Decoded Picture Buffer
+// used in H264 decoders.
+
+#ifndef CONTENT_COMMON_GPU_MEDIA_H264_DPB_H_
+#define CONTENT_COMMON_GPU_MEDIA_H264_DPB_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_vector.h"
+#include "content/common/gpu/media/h264_parser.h"
+
+namespace content {
+
+// A picture (a frame or a field) in the H.264 spec sense.
+// See spec at http://www.itu.int/rec/T-REC-H.264
+struct H264Picture {
+  enum Field {
+    FIELD_NONE,
+    FIELD_TOP,
+    FIELD_BOTTOM,
+  };
+
+  // Values calculated per H.264 specification or taken from slice header.
+  // See spec for more details on each (some names have been converted from
+  // CamelCase in spec to Chromium-style names).
+  int top_field_order_cnt;
+  int bottom_field_order_cnt;
+  int pic_order_cnt;
+  int pic_order_cnt_msb;
+  int pic_order_cnt_lsb;
+
+  int pic_num;
+  int long_term_pic_num;
+  int frame_num;  // from slice header
+  int frame_num_wrap;
+  int long_term_frame_idx;
+
+  bool idr;  // IDR picture?
+  bool ref;  // reference picture?
+  bool long_term;  // long term reference picture?
+  bool outputted;
+  // Does memory management op 5 needs to be executed after this
+  // picture has finished decoding?
+  bool mem_mgmt_5;
+
+  Field field;
+
+  // Values from slice_hdr to be used during reference marking and
+  // memory management after finishing this picture.
+  bool long_term_reference_flag;
+  bool adaptive_ref_pic_marking_mode_flag;
+  H264DecRefPicMarking ref_pic_marking[H264SliceHeader::kRefListSize];
+
+  typedef std::vector<H264Picture*> PtrVector;
+};
+
+// DPB - Decoded Picture Buffer.
+// Stores decoded pictures that will be used for future display
+// and/or reference.
+class H264DPB {
+ public:
+  H264DPB();
+  ~H264DPB();
+
+  // Remove unused (not reference and already outputted) pictures from DPB.
+  void RemoveUnused();
+
+  // Remove a picture by its pic_order_cnt.
+  void RemoveByPOC(int poc);
+
+  // Clear DPB.
+  void Clear();
+
+  // Store picture in DPB. DPB takes ownership of its resources.
+  void StorePic(H264Picture* pic);
+
+  // Return the number of reference pictures in DPB.
+  int CountRefPics();
+
+  // Mark all pictures in DPB as unused for reference.
+  void MarkAllUnusedForRef();
+
+  // Return a short-term reference picture by its pic_num.
+  H264Picture* GetShortRefPicByPicNum(int pic_num);
+
+  // Return a long-term reference picture by its long_term_pic_num.
+  H264Picture* GetLongRefPicByLongTermPicNum(int pic_num);
+
+  // Return the short reference picture with lowest frame_num. Used for sliding
+  // window memory management.
+  H264Picture* GetLowestFrameNumWrapShortRefPic();
+
+  // Append all pictures that have not been outputted yet to the passed |out|
+  // vector, sorted by lowest pic_order_cnt (in output order).
+  void GetNotOutputtedPicsAppending(H264Picture::PtrVector& out);
+
+  // Append all short term reference pictures to the passed |out| vector.
+  void GetShortTermRefPicsAppending(H264Picture::PtrVector& out);
+
+  // Append all long term reference pictures to the passed |out| vector.
+  void GetLongTermRefPicsAppending(H264Picture::PtrVector& out);
+
+  // Iterators for direct access to DPB contents.
+  // Will be invalidated after any of Remove* calls.
+  typedef ScopedVector<H264Picture> Pictures;
+  Pictures::iterator begin() { return pics_.begin(); }
+  Pictures::iterator end() { return pics_.end(); }
+  Pictures::reverse_iterator rbegin() { return pics_.rbegin(); }
+  Pictures::reverse_iterator rend() { return pics_.rend(); }
+
+  size_t size() const { return pics_.size(); }
+  bool IsFull() const { return pics_.size() == kDPBMaxSize; }
+
+  // Per H264 spec, increase to 32 if interlaced video is supported.
+  enum { kDPBMaxSize = 16 };
+
+ private:
+  // Remove a picture from DPB, freeing its resources.
+  void RemovePic(const Pictures::iterator iter);
+
+  Pictures pics_;
+
+  DISALLOW_COPY_AND_ASSIGN(H264DPB);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_H264_DPB_H_
+