Move logic for calculating needed bitrate overhead used by NACK and FEC to VideoSender.

webrtc/modules/video_coding/protection_bitrate_calculator.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_PROTECTION_BITRATE_CALCULATOR_H_
+#define WEBRTC_MODULES_VIDEO_CODING_PROTECTION_BITRATE_CALCULATOR_H_
+
+#include <list>
+#include <memory>
+
+#include "webrtc/base/criticalsection.h"
+#include "webrtc/modules/include/module_common_types.h"
+#include "webrtc/modules/video_coding/include/video_coding.h"
+#include "webrtc/modules/video_coding/media_opt_util.h"
+#include "webrtc/system_wrappers/include/clock.h"
+
+namespace webrtc {
+
+// ProtectionBitrateCalculator calculates the calculates how much of the

[stefan-webrtc, 2016/05/19 12:52:40]

-"calculates the"

[perkj_webrtc, 2016/06/01 20:55:23]

Done.

+// allocated network capacity that can be used by an encoder and how much that
+// is needed for protection packets such as FEC and NACK. It uses an

[stefan-webrtc, 2016/05/19 12:52:40]

Maybe call it redundant packets instead?

[perkj_webrtc, 2016/06/01 20:55:23]

Done.

+// implementation of |VCMProtectionCallback| to set new FEC parameters and get
+// the bitrate currently used for FEC and NACK.
+// Usage:
+// Setup by calling SetProtectionMethod and SetEncodingData.
+// For each encoded image, call UpdateWithEncodedData.
+// Each time the bandwidth estimate change, call SetTargetRates. SetTargetRates
+// will return the bitrate that can be used by an encoder.
+class ProtectionBitrateCalculator {
+ public:
+  explicit ProtectionBitrateCalculator(

[stefan-webrtc, 2016/05/19 12:52:40]

Remove explicit

[perkj_webrtc, 2016/06/01 20:55:23]

Done.

+      Clock* clock,
+      VCMProtectionCallback* protection_callback);
+  ~ProtectionBitrateCalculator();
+
+  void SetProtectionMethod(bool enable_fec, bool enable_nack);

[stefan-webrtc, 2016/05/19 12:52:40]

Would it make sense to somehow document the thread model now that we're
refactoring this a bit?

[perkj_webrtc, 2016/06/01 20:55:23]

Added a short note about thread safety.

+
+  // Informs media optimization of initial encoding state.
+  void SetEncodingData(uint32_t estimated_bitrate_bps,
+                       uint16_t width,
+                       uint16_t height,
+                       uint32_t frame_rate,
+                       size_t num_temporal_layers,
+                       size_t mtu);
+
+  // Returns target rate for the encoder given the channel parameters.
+  // Inputs:  estimated_bitrate_bps - the estimated network bitrate in bits/s.
+  //          fraction_lost - packet loss rate in % in the network.
+  //          round_trip_time_ms - round trip time in milliseconds.
+  uint32_t SetTargetRates(uint32_t estimated_bitrate_bps,
+                          uint8_t fraction_lost,
+                          int64_t round_trip_time_ms);
+
+  // Informs of encoded output.
+  void UpdateWithEncodedData(const EncodedImage& encoded_image);
+
+  uint32_t SentFrameRate();
+  uint32_t SentBitRate();

[stefan-webrtc, 2016/05/19 12:52:40]

It's a bit weird that this class is named something with protection, and then it
also keeps track of framerate and bitrate stats...

[perkj_webrtc, 2016/06/01 20:55:23]

Removed. Now relies on fps as an input parameter from the send_stats proxy.

+
+ private:
+  enum { kBitrateAverageWinMs = 1000 };
+
+  void PurgeOldFrameSamples(int64_t now_ms)
+      EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  void UpdateSentBitrate(int64_t now_ms) EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  void UpdateSentFramerate() EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+
+  uint32_t SentFrameRateInternal() EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+
+  // Protect all members.
+  rtc::CriticalSection crit_sect_;
+  Clock* const clock_;
+  VCMProtectionCallback* const protection_callback_;
+
+  std::unique_ptr<media_optimization::VCMLossProtectionLogic> loss_prot_logic_
+      GUARDED_BY(crit_sect_);
+  size_t max_payload_size_ GUARDED_BY(crit_sect_);
+  struct EncodedFrameSample;

[stefan-webrtc, 2016/05/19 12:52:40]

Move this to before all members instead to not mix forward declarations with
members.

[perkj_webrtc, 2016/06/01 20:55:23]

Done.

+  std::list<EncodedFrameSample> encoded_frame_samples_ GUARDED_BY(crit_sect_);
+  uint32_t avg_sent_bit_rate_bps_ GUARDED_BY(crit_sect_);
+  uint32_t avg_sent_framerate_ GUARDED_BY(crit_sect_);
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(ProtectionBitrateCalculator);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_VIDEO_CODING_PROTECTION_BITRATE_CALCULATOR_H_