media/base/video_frame_pool.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_BASE_VIDEO_FRAME_POOL_H_
   6 #define MEDIA_BASE_VIDEO_FRAME_POOL_H_
   7
   8 #include "media/base/media_export.h"
   9 #include "media/base/video_frame.h"
  10
  11 namespace media {
  12
  13 // Simple VideoFrame pool used to avoid unnecessarily allocating and destroying
  14 // VideoFrame objects. The pool manages the memory for the VideoFrame
  15 // returned by CreateFrame(). When one of these VideoFrames is destroyed,
  16 // the memory is returned to the pool for use by a subsequent CreateFrame()
  17 // call. The memory in the pool is retained for the life of the
  18 // VideoFramePool object. If the parameters passed to CreateFrame() change
  19 // during the life of this object, then the memory used by frames with the old
  20 // parameter values will be purged from the pool.
  21 class MEDIA_EXPORT VideoFramePool {
  22  public:
  23   VideoFramePool();
  24   ~VideoFramePool();
  25
  26   // Returns a frame from the pool that matches the specified
  27   // parameters or creates a new frame if no suitable frame exists in
  28   // the pool. The pool is drained if no matching frame is found.
  29   // The buffer for the new frame will be zero initialized.  Reused frames will
  30   // not be zero initialized.
  31   scoped_refptr<VideoFrame> CreateFrame(VideoPixelFormat format,
  32                                         const gfx::Size& coded_size,
  33                                         const gfx::Rect& visible_rect,
  34                                         const gfx::Size& natural_size,
  35                                         base::TimeDelta timestamp);
  36
  37 protected:
  38   friend class VideoFramePoolTest;
  39
  40   // Returns the number of frames in the pool for testing purposes.
  41   size_t GetPoolSizeForTesting() const;
  42
  43  private:
  44   class PoolImpl;
  45   scoped_refptr<PoolImpl> pool_;
  46
  47   DISALLOW_COPY_AND_ASSIGN(VideoFramePool);
  48 };
  49
  50 }  // namespace media
  51
  52 #endif  // MEDIA_BASE_VIDEO_FRAME_POOL_H_