初步添加twcc rtcp发送逻辑

src/Rtcp/RtcpFCI.cpp

@@ -428,8 +428,8 @@ static int16_t getRecvDelta(SymbolStatus status, uint8_t *&ptr, const uint8_t *e
     return delta;
 }
 
-map<uint16_t, std::pair<SymbolStatus, uint32_t/*stamp*/> > FCI_TWCC::getPacketChunkList(size_t total_size) const {
-    map<uint16_t, std::pair<SymbolStatus, uint32_t> > ret;
+map<uint16_t, std::pair<SymbolStatus, int16_t/*stamp*/> > FCI_TWCC::getPacketChunkList(size_t total_size) const {
+    map<uint16_t, std::pair<SymbolStatus, int16_t> > ret;
     auto ptr = (uint8_t *) this + kSize;
     auto end = (uint8_t *) this + total_size;
     CHECK(ptr < end);

src/Rtcp/RtcpFCI.h

@@ -353,7 +353,7 @@ public:
     //单位64ms
     uint32_t getReferenceTime() const;
     uint16_t getPacketCount() const;
-    map<uint16_t, std::pair<SymbolStatus, uint32_t/*recv delta,单位为250us*/> > getPacketChunkList(size_t total_size) const;
+    map<uint16_t/*rtp ext seq*/, std::pair<SymbolStatus, int16_t/*recv delta,单位为250us*/> > getPacketChunkList(size_t total_size) const;
 
 private:
     //base sequence number,基础序号,本次反馈的第一个包的序号;也就是RTP扩展头的序列号

webrtc/RtpExt.cpp

@@ -239,7 +239,7 @@ string RtpExt::dumpString() const {
             break;
         }
         case RtpExtType::transport_cc : {
-            printer << "twcc seq:" << getTransportCCSeq();
+            printer << "twcc ext seq:" << getTransportCCSeq();
             break;
         }
         case RtpExtType::sdes_mid : {
@@ -546,6 +546,10 @@ RtpExtType RtpExt::getType() const {
     return _type;
 }
 
+RtpExt::operator bool() const {
+    return _ext != nullptr;
+}
+
 RtpExtContext::RtpExtContext(const RtcMedia &m){
     for (auto &ext : m.extmap) {
         auto ext_type = RtpExt::getExtType(ext.ext);
@@ -566,8 +570,9 @@ void RtpExtContext::setRid(uint32_t ssrc, const string &rid) {
     _ssrc_to_rid[ssrc] = rid;
 }
 
-void RtpExtContext::changeRtpExtId(const RtpHeader *header, bool is_recv, string *rid_ptr) {
+RtpExt RtpExtContext::changeRtpExtId(const RtpHeader *header, bool is_recv, string *rid_ptr, RtpExtType type) {
     string rid, repaired_rid;
+    RtpExt ret;
     auto ext_map = RtpExt::getExtValue(header);
     for (auto &pr : ext_map) {
         if (is_recv) {
@@ -596,10 +601,13 @@ void RtpExtContext::changeRtpExtId(const RtpHeader *header, bool is_recv, string
             //重新赋值ext id为客户端sdp声明的类型
             pr.second.setExtId(it->second);
         }
+        if (pr.second.getType() == type) {
+            ret = pr.second;
+        }
     }
 
     if (!is_recv) {
-        return;
+        return ret;
     }
     if (rid.empty()) {
         rid = repaired_rid;
@@ -619,6 +627,7 @@ void RtpExtContext::changeRtpExtId(const RtpHeader *header, bool is_recv, string
     if (rid_ptr) {
         *rid_ptr = rid;
     }
+    return ret;
 }
 
 void RtpExtContext::setOnGetRtp(OnGetRtp cb) {

webrtc/RtpExt.h

@@ -52,7 +52,7 @@ class RtpExt {
 public:
     template<typename Type>
     friend void appendExt(map<uint8_t, RtpExt> &ret, uint8_t *ptr, const uint8_t *end);
-
+    friend class RtpExtContext;
     ~RtpExt() = default;
 
     static map<uint8_t/*id*/, RtpExt/*data*/> getExtValue(const RtpHeader *header);
@@ -94,8 +94,10 @@ public:
 
     void setExtId(uint8_t ext_id);
     void clearExt();
+    operator bool () const;
 
 private:
+    RtpExt() = default;
     RtpExt(void *ptr, bool one_byte_ext, const char *str, size_t size);
     const char *data() const;
     size_t size() const;
@@ -122,7 +124,7 @@ public:
     void setOnGetRtp(OnGetRtp cb);
     string getRid(uint32_t ssrc) const;
     void setRid(uint32_t ssrc, const string &rid);
-    void changeRtpExtId(const RtpHeader *header, bool is_recv, string *rid_ptr = nullptr);
+    RtpExt changeRtpExtId(const RtpHeader *header, bool is_recv, string *rid_ptr = nullptr, RtpExtType type = RtpExtType::padding);
 
 private:
     void onGetRtp(uint8_t pt, uint32_t ssrc, const string &rid);

webrtc/TwccContext.cpp

+/*
+ * Copyright (c) 2021 The ZLMediaKit project authors. All Rights Reserved.
+ *
+ * This file is part of ZLMediaKit(https://github.com/xia-chu/ZLMediaKit).
+ *
+ * Use of this source code is governed by MIT license that can be found in the
+ * LICENSE file in the root of the source tree. All contributing project authors
+ * may be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "TwccContext.h"
+
+enum class ExtSeqStatus : int {
+    normal = 0,
+    looped,
+    jumped,
+};
+
+void TwccContext::onRtp(uint16_t twcc_ext_seq) {
+    switch ((ExtSeqStatus) checkSeqStatus(twcc_ext_seq)) {
+        case ExtSeqStatus::jumped: /*回环后，收到回环前的大ext seq包,过滤掉*/ return;
+        case ExtSeqStatus::looped: /*回环，触发发送twcc rtcp*/ onSendTwcc(); break;
+        case ExtSeqStatus::normal: break;
+        default: /*不可达*/assert(0); break;
+    }
+
+    auto result = _rtp_recv_status.emplace(twcc_ext_seq, _ticker.createdTime());
+    if (!result.second) {
+        WarnL << "recv same twcc ext seq:" << twcc_ext_seq;
+        return;
+    }
+
+    _max_stamp = result.first->second;
+    if (!_min_stamp) {
+        _min_stamp = _max_stamp;
+    }
+
+    if (checkIfNeedSendTwcc()) {
+        //其他匹配条件立即发送twcc
+        onSendTwcc();
+    }
+}
+
+bool TwccContext::checkIfNeedSendTwcc() const {
+    auto size = _rtp_recv_status.size();
+    if (!size) {
+        return false;
+    }
+    if (size >= kMaxSeqDelta) {
+        return true;
+    }
+    auto delta_ms = _max_stamp - _min_stamp;
+    if (delta_ms >= kMaxTimeDelta) {
+        return true;
+    }
+    return false;
+}
+
+int TwccContext::checkSeqStatus(uint16_t twcc_ext_seq) const {
+    if (_rtp_recv_status.empty()) {
+        return (int) ExtSeqStatus::normal;
+    }
+    auto max = _rtp_recv_status.rbegin()->first;
+    if (max > 0xFF00 && twcc_ext_seq < 0xFF) {
+        //发生回环了
+        TraceL << "rtp twcc ext seq looped:" << max << " -> " << twcc_ext_seq;
+        return (int) ExtSeqStatus::looped;
+    }
+    if (twcc_ext_seq - max > 0xFFFF / 2) {
+        TraceL << "rtp twcc ext seq jumped:" << max << " -> " << twcc_ext_seq;
+        return (int) ExtSeqStatus::jumped;
+    }
+    return (int) ExtSeqStatus::normal;
+}
+
+void TwccContext::onSendTwcc() {
+    auto max = _rtp_recv_status.rbegin()->first;
+    auto begin = _rtp_recv_status.begin();
+    auto min = begin->first;
+    auto ref_time = begin->second;
+    DebugL << "base_seq:" << min << ",pkt_status_count:" << max + 1 - min << ",ref time:" << ref_time / 64
+           << ", fb count:" << (int) (_twcc_pkt_count++);
+    for (auto i = min; i <= max; ++i) {
+        auto it = _rtp_recv_status.find(i);
+        if (it == _rtp_recv_status.end()) {
+            DebugL << "rtp seq:" << i << ",packet status:" << 0 /*not recved*/ << ",delta_ms:" << 0;
+        } else {
+            auto delta_ms = it->second - ref_time;
+            DebugL << "rtp seq:" << i << ",packet status:" << 1 /*recved*/ << ",delta_ms:" << delta_ms;
+        }
+    }
+    clearStatus();
+}
+
+void TwccContext::clearStatus() {
+    _rtp_recv_status.clear();
+    _min_stamp = 0;
+}

webrtc/TwccContext.h

+/*
+ * Copyright (c) 2021 The ZLMediaKit project authors. All Rights Reserved.
+ *
+ * This file is part of ZLMediaKit(https://github.com/xia-chu/ZLMediaKit).
+ *
+ * Use of this source code is governed by MIT license that can be found in the
+ * LICENSE file in the root of the source tree. All contributing project authors
+ * may be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef ZLMEDIAKIT_TWCCCONTEXT_H
+#define ZLMEDIAKIT_TWCCCONTEXT_H
+
+#include <stdint.h>
+#include <map>
+#include "Util/TimeTicker.h"
+using namespace toolkit;
+
+class TwccContext {
+public:
+    //每个twcc rtcp包最多表明的rtp ext seq增量
+    static constexpr size_t kMaxSeqDelta = 20;
+    //每个twcc rtcp包发送的最大时间间隔，单位毫秒
+    static constexpr size_t kMaxTimeDelta = 64;
+
+    TwccContext() = default;
+    ~TwccContext() = default;
+
+    void onRtp(uint16_t twcc_ext_seq);
+
+private:
+    void onSendTwcc();
+    bool checkIfNeedSendTwcc() const;
+    int checkSeqStatus(uint16_t twcc_ext_seq) const;
+    void clearStatus();
+
+private:
+    Ticker _ticker;
+    uint64_t _min_stamp = 0;
+    uint64_t _max_stamp;
+    std::map<uint32_t /*twcc_ext_seq*/, uint64_t/*recv time in ms*/> _rtp_recv_status;
+    uint8_t _twcc_pkt_count = 0;
+};
+
+
+#endif //ZLMEDIAKIT_TWCCCONTEXT_H

webrtc/WebRtcTransport.cpp

@@ -808,7 +808,10 @@ void WebRtcTransportImp::onRtp(const char *buf, size_t len) {
 
     //修改ext id至统一
     string rid;
-    track->rtp_ext_ctx->changeRtpExtId(rtp, true, &rid);
+    auto twcc_ext = track->rtp_ext_ctx->changeRtpExtId(rtp, true, &rid, RtpExtType::transport_cc);
+    if (twcc_ext && !is_rtx) {
+        _twcc_ctx.onRtp(twcc_ext.getTransportCCSeq());
+    }
 
     auto &ref = track->rtp_channel[rid];
     if (!ref) {

webrtc/WebRtcTransport.h

@@ -24,6 +24,7 @@
 #include "Rtcp/RtcpFCI.h"
 #include "Nack.h"
 #include "Network/Session.h"
+#include "TwccContext.h"
 
 using namespace toolkit;
 using namespace mediakit;
@@ -251,4 +252,5 @@ private:
     unordered_map<uint8_t/*pt*/, std::pair<bool/*is rtx*/,MediaTrack::Ptr> > _pt_to_track;
     //根据rtcp的ssrc获取相关信息，收发rtp和rtx的ssrc都会记录
     unordered_map<uint32_t/*ssrc*/, MediaTrack::Ptr> _ssrc_to_track;
+    TwccContext _twcc_ctx;
 };
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