FrameBuffer for the new jitter buffer.

webrtc/modules/video_coding/frame_buffer2.h

+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_VIDEO_CODING_FRAME_BUFFER2_H_
+#define WEBRTC_MODULES_VIDEO_CODING_FRAME_BUFFER2_H_
+
+#include <array>
+#include <map>
+#include <memory>
+#include <utility>
+
+#include "webrtc/base/criticalsection.h"
+#include "webrtc/base/event.h"
+#include "webrtc/base/thread_annotations.h"
+#include "webrtc/modules/video_coding/frame_object.h"
+#include "webrtc/modules/video_coding/jitter_estimator.h"
+#include "webrtc/modules/video_coding/sequence_number_util.h"
+#include "webrtc/modules/video_coding/timing.h"
+#include "webrtc/system_wrappers/include/clock.h"
+
+namespace webrtc {
+namespace video_coding {
+
+class FrameBuffer {
+ public:
+  FrameBuffer(Clock* clock,
+              VCMJitterEstimator* jitter_estimator,
+              VCMTiming* timing);
+
+  // Insert a frame into the frame buffer.
+  void InsertFrame(std::unique_ptr<FrameObject> frame);
+
+  // Get the next frame for decoding. Will return at latest after
+  // |max_wait_time|, with either a managed FrameObject or an empty
+  // unique ptr if there is no available frame for decoding.
+  std::unique_ptr<FrameObject> NextFrame(int64_t max_wait_time);

[danilchap, 2016/05/13 15:33:56]

max_wait_time_ms

[philipel, 2016/05/17 09:16:41]

Done.

+
+ private:
+  // The maximum age of a frame stored in the frame buffer, compared to
+  // |newest_picture_id_|.
+  static const int kMaxFrameAge = 4096;
+
+  // The maximum number of frames stored in the frame buffer.
+  static const int kMaxStoredFrames = 256;
+
+  // The maximum number of spatial layers.
+  static const int kMaxSpatialLayers = 5;
+
+  // Determines whether a frame is continuous.
+  bool IsContinuous(const FrameObject& frame) const
+      EXCLUSIVE_LOCKS_REQUIRED(crit_);
+
+  // For every picture id, keep information whether a frame has been decoded
+  // for a given spatial layer.
+  std::map<uint16_t,
+          std::array<bool, kMaxSpatialLayers>,
+          DescendingSeqNumComp<uint16_t>> decoded_frames_ GUARDED_BY(crit_);
+
+  // Comparator used to sort frames, first on their picture id, and second
+  // on their spatial layer.
+  struct FrameComp {
+    bool operator()(const std::pair<uint16_t, uint8_t>& f1,

[danilchap, 2016/05/13 15:33:56]

probably better make this static if you want to keep it.

[philipel, 2016/05/17 09:16:41]

I don't really understand...

[danilchap, 2016/05/17 12:35:02]

i.e. static bool operator()(<same as before>) const;
to help optimizer and tools. though I do not know any case where it would
matter.

[philipel, 2016/05/17 14:57:04]

Acknowledged.

+                    const std::pair<uint16_t, uint8_t>& f2) const {
+                      // first = picture id
+                      // second = spatial layer
+                      if (f1.first == f2.first)
+                        return f1.second < f2.second;
+                      return AheadOf(f2.first, f1.first);
+                    }
+  };
+
+  // The actual buffer that holds the FrameObjects, the key being the
+  // tuple (picture id, spatial layer).
+  std::map<std::pair<uint16_t, uint8_t>,

[danilchap, 2016/05/13 15:33:56]

may be instead of using pair as key and creating special comparer it would be
clearer to create special key structure:
struct FrameId {
  FrameId(uint16_t picture_id, uint8_t spatial_layer);
  uint16_t picture_id;
  uint8_t spatial_layer;
  bool operator<(const FrameId& other) const;
};

[philipel, 2016/05/17 09:16:41]

Acknowledged.

+           std::unique_ptr<FrameObject>,
+           FrameComp> frames_ GUARDED_BY(crit_);
+
+  rtc::CriticalSection crit_;
+  Clock* clock_;

[danilchap, 2016/05/13 15:33:56]

Clock* const clock_;

[philipel, 2016/05/17 09:16:41]

Done.

+  rtc::Event frame_inserted_event_;
+  VCMJitterEstimator* jitter_estimator_;

[danilchap, 2016/05/13 15:33:57]

VCMJitterEstimator* const jitter_estimator_;

[philipel, 2016/05/17 09:16:41]

Done.

+  VCMTiming* timing_;

[danilchap, 2016/05/13 15:33:56]

const VCMTiming* const timing_;

[philipel, 2016/05/17 09:16:41]

Done.

+  int newest_picture_id_ GUARDED_BY(crit_);
+};
+
+
+}  // namespace video_coding
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_VIDEO_CODING_FRAME_BUFFER2_H_