初步实现twcc rtcp发送

webrtc/TwccContext.cpp

@@ -19,10 +19,10 @@ enum class ExtSeqStatus : int {
     jumped,
 };
 
-void TwccContext::onRtp(uint16_t twcc_ext_seq) {
+void TwccContext::onRtp(uint32_t ssrc, 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::looped: /*回环，触发发送twcc rtcp*/ onSendTwcc(ssrc); break;
         case ExtSeqStatus::normal: break;
         default: /*不可达*/assert(0); break;
     }
@@ -40,7 +40,7 @@ void TwccContext::onRtp(uint16_t twcc_ext_seq) {
 
     if (checkIfNeedSendTwcc()) {
         //其他匹配条件立即发送twcc
-        onSendTwcc();
+        onSendTwcc(ssrc);
     }
 }
 
@@ -76,11 +76,12 @@ int TwccContext::checkSeqStatus(uint16_t twcc_ext_seq) const {
     return (int) ExtSeqStatus::normal;
 }
 
-void TwccContext::onSendTwcc() {
+void TwccContext::onSendTwcc(uint32_t ssrc) {
     auto max = _rtp_recv_status.rbegin()->first;
     auto begin = _rtp_recv_status.begin();
     auto min = begin->first;
-    auto ref_time = begin->second;
+    auto ref_time = begin->second >> 6;
+    auto last_time = ref_time << 6;
     FCI_TWCC::TwccPacketStatus status;
     for (auto seq = min; seq <= max; ++seq) {
         int16_t delta = 0;
@@ -88,20 +89,20 @@ void TwccContext::onSendTwcc() {
         auto it = _rtp_recv_status.find(seq);
         if (it != _rtp_recv_status.end()) {
             //recv delta,单位为250us,1ms等于4x250us
-            delta = (int16_t) (4 * ((int64_t) it->second - (int64_t) ref_time));
+            delta = (int16_t) (4 * ((int64_t) it->second - (int64_t) last_time));
             if (delta < 0 || delta > 0xFF) {
                 symbol = SymbolStatus::large_delta;
             } else {
                 symbol = SymbolStatus::small_delta;
             }
-            ref_time = it->second;
+            last_time = it->second;
         }
         status.emplace(seq, std::make_pair(symbol, delta));
     }
-    auto fci = FCI_TWCC::create(ref_time / 64, _twcc_pkt_count, status);
-    InfoL << ((FCI_TWCC *) (fci.data()))->dumpString(fci.size());
-
-    ++_twcc_pkt_count;
+    auto fci = FCI_TWCC::create(ref_time, _twcc_pkt_count++, status);
+    if (_cb) {
+        _cb(ssrc, std::move(fci));
+    }
     clearStatus();
 }
 
@@ -109,3 +110,7 @@ void TwccContext::clearStatus() {
     _rtp_recv_status.clear();
     _min_stamp = 0;
 }
+
+void TwccContext::setOnSendTwccCB(TwccContext::onSendTwccCB cb) {
+    _cb = std::move(cb);
+}

webrtc/TwccContext.h

@@ -18,18 +18,20 @@ using namespace toolkit;
 
 class TwccContext {
 public:
+    using onSendTwccCB = function<void(uint32_t ssrc, string fci)>;
     //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;
+    static constexpr size_t kMaxTimeDelta = 256;
 
     TwccContext() = default;
     ~TwccContext() = default;
 
-    void onRtp(uint16_t twcc_ext_seq);
+    void onRtp(uint32_t ssrc, uint16_t twcc_ext_seq);
+    void setOnSendTwccCB(onSendTwccCB cb);
 
 private:
-    void onSendTwcc();
+    void onSendTwcc(uint32_t ssrc);
     bool checkIfNeedSendTwcc() const;
     int checkSeqStatus(uint16_t twcc_ext_seq) const;
     void clearStatus();
@@ -40,6 +42,7 @@ private:
     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;
+    onSendTwccCB _cb;
 };
 
 

webrtc/WebRtcTransport.cpp

@@ -332,6 +332,10 @@ void WebRtcTransportImp::onCreate(){
         }
         return true;
     }, getPoller());
+
+    _twcc_ctx.setOnSendTwccCB([this](uint32_t ssrc, string fci) {
+        onSendTwcc(ssrc, fci);
+    });
 }
 
 WebRtcTransportImp::WebRtcTransportImp(const EventPoller::Ptr &poller) : WebRtcTransport(poller) {
@@ -810,7 +814,7 @@ void WebRtcTransportImp::onRtp(const char *buf, size_t len) {
     string 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());
+        _twcc_ctx.onRtp(ssrc, twcc_ext.getTransportCCSeq());
     }
 
     auto &ref = track->rtp_channel[rid];
@@ -865,6 +869,13 @@ void WebRtcTransportImp::onSendNack(MediaTrack &track, const FCI_NACK &nack, uin
     sendRtcpPacket((char *) rtcp.get(), rtcp->getSize(), true);
 }
 
+void WebRtcTransportImp::onSendTwcc(uint32_t ssrc, const string &twcc_fci) {
+    auto rtcp = RtcpFB::create(RTPFBType::RTCP_RTPFB_TWCC, twcc_fci.data(), twcc_fci.size());
+    rtcp->ssrc = htons(0);
+    rtcp->ssrc_media = htonl(ssrc);
+    sendRtcpPacket((char *) rtcp.get(), rtcp->getSize(), true);
+}
+
 ///////////////////////////////////////////////////////////////////
 
 void WebRtcTransportImp::onSortedRtp(MediaTrack &track, const string &rid, RtpPacket::Ptr rtp) {

webrtc/WebRtcTransport.h

@@ -217,6 +217,7 @@ private:
 
     void onSortedRtp(MediaTrack &track, const string &rid, RtpPacket::Ptr rtp);
     void onSendNack(MediaTrack &track, const FCI_NACK &nack, uint32_t ssrc);
+    void onSendTwcc(uint32_t ssrc, const string &twcc_fci);
     void createRtpChannel(const string &rid, uint32_t ssrc, MediaTrack &track);
     void registerSelf();
     void unregisterSelf();