media/base/decoder_buffer_queue.h

   1 // Copyright (c) 2012 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_DECODER_BUFFER_QUEUE_H_
   6 #define MEDIA_BASE_DECODER_BUFFER_QUEUE_H_
   7
   8 #include <deque>
   9
  10 #include "base/memory/ref_counted.h"
  11 #include "base/time.h"
  12 #include "media/base/media_export.h"
  13
  14 namespace media {
  15
  16 class DecoderBuffer;
  17
  18 // Maintains a queue of DecoderBuffers in increasing timestamp order.
  19 //
  20 // Individual buffer durations are ignored when calculating the duration of the
  21 // queue i.e., the queue must have at least 2 in-order buffers to calculate
  22 // duration.
  23 //
  24 // Not thread safe: access must be externally synchronized.
  25 class MEDIA_EXPORT DecoderBufferQueue {
  26  public:
  27   DecoderBufferQueue();
  28   ~DecoderBufferQueue();
  29
  30   // Push |buffer| to the end of the queue. If |buffer| is queued out of order
  31   // it will be excluded from duration calculations.
  32   //
  33   // It is invalid to push an end-of-stream |buffer|.
  34   void Push(const scoped_refptr<DecoderBuffer>& buffer);
  35
  36   // Pops a DecoderBuffer from the front of the queue.
  37   //
  38   // It is invalid to call Pop() on an empty queue.
  39   scoped_refptr<DecoderBuffer> Pop();
  40
  41   // Removes all queued buffers.
  42   void Clear();
  43
  44   // Returns true if this queue is empty.
  45   bool IsEmpty();
  46
  47   // Returns the duration of encoded data stored in this queue as measured by
  48   // the timestamps of the earliest and latest buffers, ignoring out of order
  49   // buffers.
  50   //
  51   // Returns zero if the queue is empty.
  52   base::TimeDelta Duration();
  53
  54  private:
  55   typedef std::deque<scoped_refptr<DecoderBuffer> > Queue;
  56   Queue queue_;
  57
  58   // A subset of |queue_| that contains buffers that are in strictly
  59   // increasing timestamp order. Used to calculate Duration() while ignoring
  60   // out-of-order buffers.
  61   Queue in_order_queue_;
  62
  63   base::TimeDelta earliest_valid_timestamp_;
  64
  65   DISALLOW_COPY_AND_ASSIGN(DecoderBufferQueue);
  66 };
  67
  68 }  // namespace media
  69
  70 #endif  // MEDIA_BASE_DECODER_BUFFER_QUEUE_H_