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0367d1a1fb
Currently we send Nack as soon as we see packets out of order(a skip in packet sequence number). Sometimes this is not necessary because these "missing" packets just late for a couple of millisecond, or these packets can be recovered by FEC. This CL add a field trial parameter to configure a delay before sending Nack. Bug: webrtc:9953 Change-Id: Ia8f5995d874f7c55a74091bc90d8395b9b88e66b Reviewed-on: https://webrtc-review.googlesource.com/c/109080 Reviewed-by: Stefan Holmer <stefan@webrtc.org> Reviewed-by: Philip Eliasson <philipel@webrtc.org> Commit-Queue: Ying Wang <yinwa@webrtc.org> Cr-Commit-Position: refs/heads/master@{#25488}
111 lines
3.7 KiB
C++
111 lines
3.7 KiB
C++
/*
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* Copyright (c) 2016 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_VIDEO_CODING_NACK_MODULE_H_
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#define MODULES_VIDEO_CODING_NACK_MODULE_H_
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#include <map>
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#include <set>
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#include <vector>
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#include "modules/include/module.h"
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#include "modules/include/module_common_types.h"
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#include "modules/video_coding/histogram.h"
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#include "rtc_base/criticalsection.h"
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#include "rtc_base/numerics/sequence_number_util.h"
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#include "rtc_base/thread_annotations.h"
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#include "system_wrappers/include/clock.h"
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namespace webrtc {
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class NackModule : public Module {
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public:
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NackModule(Clock* clock,
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NackSender* nack_sender,
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KeyFrameRequestSender* keyframe_request_sender);
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int OnReceivedPacket(uint16_t seq_num, bool is_keyframe);
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int OnReceivedPacket(uint16_t seq_num, bool is_keyframe, bool is_recovered);
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void ClearUpTo(uint16_t seq_num);
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void UpdateRtt(int64_t rtt_ms);
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void Clear();
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// Module implementation
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int64_t TimeUntilNextProcess() override;
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void Process() override;
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private:
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// Which fields to consider when deciding which packet to nack in
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// GetNackBatch.
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enum NackFilterOptions { kSeqNumOnly, kTimeOnly, kSeqNumAndTime };
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// This class holds the sequence number of the packet that is in the nack list
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// as well as the meta data about when it should be nacked and how many times
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// we have tried to nack this packet.
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struct NackInfo {
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NackInfo();
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NackInfo(uint16_t seq_num,
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uint16_t send_at_seq_num,
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int64_t created_at_time);
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uint16_t seq_num;
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uint16_t send_at_seq_num;
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int64_t created_at_time;
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int64_t sent_at_time;
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int retries;
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};
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void AddPacketsToNack(uint16_t seq_num_start, uint16_t seq_num_end)
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RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
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// Removes packets from the nack list until the next keyframe. Returns true
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// if packets were removed.
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bool RemovePacketsUntilKeyFrame() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
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std::vector<uint16_t> GetNackBatch(NackFilterOptions options)
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RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
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// Update the reordering distribution.
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void UpdateReorderingStatistics(uint16_t seq_num)
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RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
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// Returns how many packets we have to wait in order to receive the packet
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// with probability |probabilty| or higher.
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int WaitNumberOfPackets(float probability) const
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RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
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rtc::CriticalSection crit_;
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Clock* const clock_;
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NackSender* const nack_sender_;
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KeyFrameRequestSender* const keyframe_request_sender_;
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// TODO(philipel): Some of the variables below are consistently used on a
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// known thread (e.g. see |initialized_|). Those probably do not need
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// synchronized access.
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std::map<uint16_t, NackInfo, DescendingSeqNumComp<uint16_t>> nack_list_
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RTC_GUARDED_BY(crit_);
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std::set<uint16_t, DescendingSeqNumComp<uint16_t>> keyframe_list_
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RTC_GUARDED_BY(crit_);
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std::set<uint16_t, DescendingSeqNumComp<uint16_t>> recovered_list_
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RTC_GUARDED_BY(crit_);
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video_coding::Histogram reordering_histogram_ RTC_GUARDED_BY(crit_);
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bool initialized_ RTC_GUARDED_BY(crit_);
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int64_t rtt_ms_ RTC_GUARDED_BY(crit_);
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uint16_t newest_seq_num_ RTC_GUARDED_BY(crit_);
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// Only touched on the process thread.
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int64_t next_process_time_ms_;
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// Adds a delay before send nack on packet received.
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const int64_t send_nack_delay_ms_;
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};
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} // namespace webrtc
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#endif // MODULES_VIDEO_CODING_NACK_MODULE_H_
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