1 /* 2 * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef MODULES_VIDEO_CODING_NACK_MODULE_H_ 12 #define MODULES_VIDEO_CODING_NACK_MODULE_H_ 13 14 #include <map> 15 #include <vector> 16 #include <set> 17 18 #include "modules/include/module.h" 19 #include "modules/video_coding/histogram.h" 20 #include "modules/video_coding/include/video_coding_defines.h" 21 #include "modules/video_coding/packet.h" 22 #include "rtc_base/criticalsection.h" 23 #include "rtc_base/numerics/sequence_number_util.h" 24 #include "rtc_base/thread_annotations.h" 25 #include "system_wrappers/include/clock.h" 26 27 namespace webrtc { 28 29 class NackModule : public Module { 30 public: 31 NackModule(Clock* clock, 32 NackSender* nack_sender, 33 KeyFrameRequestSender* keyframe_request_sender); 34 35 int OnReceivedPacket(const VCMPacket& packet); 36 void ClearUpTo(uint16_t seq_num); 37 void UpdateRtt(int64_t rtt_ms); 38 void Clear(); 39 40 // Module implementation 41 int64_t TimeUntilNextProcess() override; 42 void Process() override; 43 44 private: 45 // Which fields to consider when deciding which packet to nack in 46 // GetNackBatch. 47 enum NackFilterOptions { kSeqNumOnly, kTimeOnly, kSeqNumAndTime }; 48 49 // This class holds the sequence number of the packet that is in the nack list 50 // as well as the meta data about when it should be nacked and how many times 51 // we have tried to nack this packet. 52 struct NackInfo { 53 NackInfo(); 54 NackInfo(uint16_t seq_num, uint16_t send_at_seq_num); 55 56 uint16_t seq_num; 57 uint16_t send_at_seq_num; 58 int64_t sent_at_time; 59 int retries; 60 }; 61 void AddPacketsToNack(uint16_t seq_num_start, uint16_t seq_num_end) 62 RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_); 63 64 // Removes packets from the nack list until the next keyframe. Returns true 65 // if packets were removed. 66 bool RemovePacketsUntilKeyFrame() RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_); 67 std::vector<uint16_t> GetNackBatch(NackFilterOptions options) 68 RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_); 69 70 // Update the reordering distribution. 71 void UpdateReorderingStatistics(uint16_t seq_num) 72 RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_); 73 74 // Returns how many packets we have to wait in order to receive the packet 75 // with probability |probabilty| or higher. 76 int WaitNumberOfPackets(float probability) const 77 RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_); 78 79 rtc::CriticalSection crit_; 80 Clock* const clock_; 81 NackSender* const nack_sender_; 82 KeyFrameRequestSender* const keyframe_request_sender_; 83 84 // TODO(philipel): Some of the variables below are consistently used on a 85 // known thread (e.g. see |initialized_|). Those probably do not need 86 // synchronized access. 87 std::map<uint16_t, NackInfo, DescendingSeqNumComp<uint16_t>> nack_list_ 88 RTC_GUARDED_BY(crit_); 89 std::set<uint16_t, DescendingSeqNumComp<uint16_t>> keyframe_list_ 90 RTC_GUARDED_BY(crit_); 91 video_coding::Histogram reordering_histogram_ RTC_GUARDED_BY(crit_); 92 bool initialized_ RTC_GUARDED_BY(crit_); 93 int64_t rtt_ms_ RTC_GUARDED_BY(crit_); 94 uint16_t newest_seq_num_ RTC_GUARDED_BY(crit_); 95 96 // Only touched on the process thread. 97 int64_t next_process_time_ms_; 98 }; 99 100 } // namespace webrtc 101 102 #endif // MODULES_VIDEO_CODING_NACK_MODULE_H_ 103