123 lines
4.4 KiB
C++
123 lines
4.4 KiB
C++
/*
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* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef MODULES_RTP_RTCP_SOURCE_ULPFEC_GENERATOR_H_
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#define MODULES_RTP_RTCP_SOURCE_ULPFEC_GENERATOR_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <list>
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#include <memory>
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#include <vector>
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#include "modules/include/module_fec_types.h"
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#include "modules/rtp_rtcp/source/forward_error_correction.h"
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#include "modules/rtp_rtcp/source/video_fec_generator.h"
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#include "rtc_base/race_checker.h"
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#include "rtc_base/rate_statistics.h"
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#include "rtc_base/synchronization/mutex.h"
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namespace webrtc {
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class FlexfecSender;
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class UlpfecGenerator : public VideoFecGenerator {
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friend class FlexfecSender;
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public:
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UlpfecGenerator(int red_payload_type, int ulpfec_payload_type, Clock* clock);
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~UlpfecGenerator();
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FecType GetFecType() const override {
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return VideoFecGenerator::FecType::kUlpFec;
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}
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absl::optional<uint32_t> FecSsrc() override { return absl::nullopt; }
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void SetProtectionParameters(const FecProtectionParams& delta_params,
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const FecProtectionParams& key_params) override;
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// Adds a media packet to the internal buffer. When enough media packets
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// have been added, the FEC packets are generated and stored internally.
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// These FEC packets are then obtained by calling GetFecPacketsAsRed().
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void AddPacketAndGenerateFec(const RtpPacketToSend& packet) override;
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// Returns the overhead, per packet, for FEC (and possibly RED).
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size_t MaxPacketOverhead() const override;
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std::vector<std::unique_ptr<RtpPacketToSend>> GetFecPackets() override;
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// Current rate of FEC packets generated, including all RTP-level headers.
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DataRate CurrentFecRate() const override;
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absl::optional<RtpState> GetRtpState() override { return absl::nullopt; }
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private:
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struct Params {
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Params();
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Params(FecProtectionParams delta_params,
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FecProtectionParams keyframe_params);
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FecProtectionParams delta_params;
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FecProtectionParams keyframe_params;
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};
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UlpfecGenerator(std::unique_ptr<ForwardErrorCorrection> fec, Clock* clock);
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// Overhead is defined as relative to the number of media packets, and not
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// relative to total number of packets. This definition is inherited from the
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// protection factor produced by video_coding module and how the FEC
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// generation is implemented.
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int Overhead() const;
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// Returns true if the excess overhead (actual - target) for the FEC is below
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// the amount |kMaxExcessOverhead|. This effects the lower protection level
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// cases and low number of media packets/frame. The target overhead is given
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// by |params_.fec_rate|, and is only achievable in the limit of large number
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// of media packets.
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bool ExcessOverheadBelowMax() const;
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// Returns true if the number of added media packets is at least
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// |min_num_media_packets_|. This condition tries to capture the effect
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// that, for the same amount of protection/overhead, longer codes
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// (e.g. (2k,2m) vs (k,m)) are generally more effective at recovering losses.
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bool MinimumMediaPacketsReached() const;
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const FecProtectionParams& CurrentParams() const;
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void ResetState();
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const int red_payload_type_;
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const int ulpfec_payload_type_;
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Clock* const clock_;
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rtc::RaceChecker race_checker_;
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const std::unique_ptr<ForwardErrorCorrection> fec_
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RTC_GUARDED_BY(race_checker_);
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ForwardErrorCorrection::PacketList media_packets_
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RTC_GUARDED_BY(race_checker_);
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absl::optional<RtpPacketToSend> last_media_packet_
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RTC_GUARDED_BY(race_checker_);
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std::list<ForwardErrorCorrection::Packet*> generated_fec_packets_
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RTC_GUARDED_BY(race_checker_);
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int num_protected_frames_ RTC_GUARDED_BY(race_checker_);
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int min_num_media_packets_ RTC_GUARDED_BY(race_checker_);
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Params current_params_ RTC_GUARDED_BY(race_checker_);
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bool keyframe_in_process_ RTC_GUARDED_BY(race_checker_);
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mutable Mutex mutex_;
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absl::optional<Params> pending_params_ RTC_GUARDED_BY(mutex_);
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RateStatistics fec_bitrate_ RTC_GUARDED_BY(mutex_);
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};
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} // namespace webrtc
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#endif // MODULES_RTP_RTCP_SOURCE_ULPFEC_GENERATOR_H_
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