Implementation of MediaCodecPlayer stage 1

media/base/android/access_unit_queue.h

+// Copyright 2015 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.
+
+#ifndef MEDIA_BASE_ANDROID_ACCESS_UNIT_QUEUE_H_
+#define MEDIA_BASE_ANDROID_ACCESS_UNIT_QUEUE_H_
+
+#include <deque>
+
+#include "base/macros.h"
+#include "base/synchronization/lock.h"
+#include "media/base/android/demuxer_stream_player_params.h"
+
+namespace media {
+
+// The queue of incoming data for MediaCodecDecoder.
+//
+// The queue is accessed on the Media thread that puts the incoming
+// data in and the Decoder thread that gets the next access unit and
+// eventually removes it from the queue.
+class AccessUnitQueue {
+ public:
+  // Information about the queue state and it's front AccessUnit

[wolenetz, 2015/05/19 21:58:37]

nit: s/it's/its/

[Tima Vaisburd, 2015/05/22 23:37:52]

Done.

+  struct Info {
+    // The unit at front
+    const AccessUnit* front_unit;
+
+    // New configs at front.
+    // If |front_unit| is defined, |configs| is null, and vice versa.
+    const DemuxerConfigs* configs;
+
+    // Current size of the queue.

[wolenetz, 2015/05/19 21:58:37]

Does presence of new configs change this size?

[Tima Vaisburd, 2015/05/22 22:48:54]

Yes, |kConfigChanged| is a placeholder access unit. I changed description,
hopefully it became clearer.

+    int length;
+
+    // Whether the queue containd End Of Stream.
+    bool has_eos;
+
+    Info()
+        : front_unit(nullptr), configs(nullptr), length(0), has_eos(false) {}
+  };
+
+  AccessUnitQueue();
+  virtual ~AccessUnitQueue();

[wolenetz, 2015/05/19 21:58:37]

hmm. AccessUnitQueue doesn't derive, nor is it derived from. Is virtual
necessary here?

[Tima Vaisburd, 2015/05/22 22:48:54]

Sorry, I can't see why it was virtual either. Removed.

+
+  // Appends the incoming data to the queue.
+  void PushBack(const DemuxerData& frames);
+
+  // Removes one access unit from the front.
+  void PopFront();
+
+  // Clears the queue
+  void Flush();
+
+  // Looks for the first key frame and if it exists,
+  // removes prior frames and returns true. If it does not

[wolenetz, 2015/05/19 21:58:37]

nit: squeeze 3rd line of comment onto end of 2nd?

[Tima Vaisburd, 2015/05/22 22:48:54]

Done.

+  // exist returns false.
+  bool SkipToKeyFrame();

[wolenetz, 2015/05/19 21:58:37]

What if there is a config prior to the keyframe?

[Tima Vaisburd, 2015/05/28 02:00:34]

As Min pointed out below, instead of going forward in time I should have gone
backward, the same way it is done currently. I think this way we will always get
the key frame that is consistent with the current configuration. I changed the
implementation of AccessUnitQueue to use the list of chunks. This allows for
some limited search backwards.

+
+  // Returns the information about the queue.
+  void GetInfo(Info* info) const;
+
+ private:
+  // The queue of access units
+  std::deque<AccessUnit> access_units_;
+
+  // The queue of corresponding configurations.
+  // Some access units has the state set to |kConfigChanged|,
+  // these units have no data and no PTS, and for each there is

[wolenetz, 2015/05/19 21:58:37]

nit ditto: squeeze comment paragraphs into longer lines.
Here and elsewhere in this CL, please.

[Tima Vaisburd, 2015/05/22 22:48:54]

Done.

+  // one entry in |demuxer_configs_|
+  std::deque<DemuxerConfigs> demuxer_configs_;
+
+  // Indicates that a unit with End Of Stream flag
+  // has been appended to the queue.
+  bool has_eos_;
+
+  // The queue works on two threads.
+  mutable base::Lock lock_;
+
+  DISALLOW_COPY_AND_ASSIGN(AccessUnitQueue);
+};
+
+}  // namespace media
+
+// For logging
+std::ostream& operator<<(std::ostream& os, const media::AccessUnit& au);

[wolenetz, 2015/05/19 21:58:37]

Hmm. Put this into demuxer_stream_player_params.h ?

[Tima Vaisburd, 2015/05/22 22:48:54]

Done.

+
+#endif  // MEDIA_BASE_ANDROID_ACCESS_UNIT_QUEUE_H_