基本完成twcc rtcp fci的生成

src/Rtcp/RtcpFCI.cpp

@@ -285,22 +285,16 @@ public:
     //获取symbollist
     vector<SymbolStatus> getSymbolList() const;
     //构造函数
-    StatusVecChunk(const vector<SymbolStatus> &status);
+    StatusVecChunk(bool symbol_bit, const vector<SymbolStatus> &status);
     //打印本对象
     string dumpString() const;
 } PACKED;
 
-StatusVecChunk::StatusVecChunk(const vector<SymbolStatus> &status) {
+StatusVecChunk::StatusVecChunk(bool symbol_bit, const vector<SymbolStatus> &status) {
+    CHECK((1 + symbol_bit) * status.size() <= 14);
     uint16_t value = 0;
     type = 1;
-    if (status.size() == 14) {
+    symbol = symbol_bit;
-        symbol = 0;
-    } else if (status.size() == 7) {
-        symbol = 1;
-    } else {
-        //非法
-        CHECK(0);
-    }
     int i = 13;
     for (auto &item : status) {
         CHECK(item <= SymbolStatus::reserved);
@@ -428,8 +422,8 @@ static int16_t getRecvDelta(SymbolStatus status, uint8_t *&ptr, const uint8_t *e
     return delta;
 }
 
-map<uint16_t, std::pair<SymbolStatus, int16_t/*stamp*/> > FCI_TWCC::getPacketChunkList(size_t total_size) const {
+FCI_TWCC::TwccPacketStatus FCI_TWCC::getPacketChunkList(size_t total_size) const {
-    map<uint16_t, std::pair<SymbolStatus, int16_t> > ret;
+    TwccPacketStatus ret;
     auto ptr = (uint8_t *) this + kSize;
     auto end = (uint8_t *) this + total_size;
     CHECK(ptr < end);
@@ -475,48 +469,83 @@ string FCI_TWCC::dumpString(size_t total_size) const {
     return std::move(printer);
 }
 
+static void appendDeltaString(string &delta_str, FCI_TWCC::TwccPacketStatus &status, int count){
+    for (auto it = status.begin(); it != status.end() && count--;) {
+        switch (it->second.first) {
+            //large delta模式先写高字节，再写低字节
+            case SymbolStatus::large_delta: delta_str.push_back((it->second.second >> 8) & 0xFF);
+                //small delta模式只写低字节
+            case SymbolStatus::small_delta: delta_str.push_back(it->second.second & 0xFF); break;
+            default: break;
+        }
+        //移除已经处理过的数据
+        it = status.erase(it);
+    }
+}
+
+string FCI_TWCC::create(uint32_t ref_time, uint8_t fb_pkt_count, TwccPacketStatus &status) {
+    string fci;
+    fci.resize(FCI_TWCC::kSize);
+    FCI_TWCC *ptr = (FCI_TWCC *) (fci.data());
+    ptr->base_seq = htons(status.begin()->first);
+    ptr->pkt_status_count = htons(status.size());
+    ptr->fb_pkt_count = fb_pkt_count;
+    ptr->ref_time[0] = (ref_time >> 16) & 0xFF;
+    ptr->ref_time[1] = (ref_time >> 8) & 0xFF;
+    ptr->ref_time[2] = (ref_time >> 0) & 0xFF;
+
+    string delta_str;
+    while (!status.empty()) {
+        {
+            //第一个rtp的状态
+            auto symbol = status.begin()->second.first;
+            int16_t count = 0;
+            for (auto &pr : status) {
+                if (++count == (0xFFFF >> 3)) {
+                    //RunLengthChunk 13个bit表明rtp个数，最多可以表述0xFFFF >> 3个rtp状态
+                    break;
+                }
+                if (pr.second.first != symbol) {
+                    //状态发送变更了，本chunk结束
+                    break;
+                }
+            }
+            if (count >= 7) {
+                //连续状态相同个数大于6个时，使用RunLengthChunk模式比较节省带宽
+                RunLengthChunk chunk(symbol, count);
+                fci.append((char *)&chunk, RunLengthChunk::kSize);
+                appendDeltaString(delta_str, status, count);
+                continue;
+            }
+        }
+
+        {
+            //StatusVecChunk模式
+            //symbol_list中元素是1个bit
+            auto symbol = 0;
+            int count = 0;
+            vector<SymbolStatus> vec;
+            for (auto &pr : status) {
+                vec.push_back(pr.second.first);
+                if (pr.second.first >= SymbolStatus::large_delta) {
+                    //symbol_list中元素是2个bit
+                    symbol = 1;
+                }
+                if ((1 + symbol) * (++count) == 14) {
+                    //symbol为0时，最多存放14个rtp的状态
+                    //symbol为1时，最多存放7个rtp的状态
+                    break;
+                }
+            }
+            StatusVecChunk chunk(symbol, vec);
+            fci.append((char *)&chunk, StatusVecChunk::kSize);
+            appendDeltaString(delta_str, status, count);
+        }
+    }
+
+    //recv delta部分
+    fci.append(delta_str);
+    return fci;
+}
+
 }//namespace mediakit
-
-#if 1
-using namespace mediakit;
-void testFCI() {
-    {
-        FCI_SLI fci(8191, 0, 63);
-        InfoL << hexdump(&fci, FCI_SLI::kSize) << fci.dumpString();
-    }
-    {
-        FCI_FIR fci(123456, 139, 456789);
-        InfoL << hexdump(&fci, FCI_FIR::kSize) << fci.dumpString();
-    }
-    {
-        auto str = FCI_REMB::create({1234, 2345, 5678}, 4 * 1024 * 1024);
-        FCI_REMB *ptr = (FCI_REMB *) str.data();
-        InfoL << hexdump(str.data(), str.size()) << ptr->dumpString();
-    }
-    {
-        FCI_NACK nack(1234, vector<bool>({1, 0, 0, 0, 1, 0, 1, 0, 1, 0}));
-        InfoL << hexdump(&nack, FCI_NACK::kSize) << nack.dumpString();
-    }
-
-    {
-        RunLengthChunk chunk(SymbolStatus::large_delta, 8024);
-        InfoL << hexdump(&chunk, RunLengthChunk::kSize) << chunk.dumpString();
-    }
-
-    auto lam = [](const initializer_list<int> &lst) {
-        vector<SymbolStatus> ret;
-        for (auto &num : lst) {
-            ret.emplace_back((SymbolStatus) num);
-        }
-        return ret;
-    };
-    {
-        StatusVecChunk chunk(lam({0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1}));
-        InfoL << hexdump(&chunk, StatusVecChunk::kSize) << chunk.dumpString();
-    }
-    {
-        StatusVecChunk chunk(lam({0, 1, 2, 2, 0, 1, 2}));
-        InfoL <<  hexdump(&chunk, StatusVecChunk::kSize) << chunk.dumpString();
-    }
-}
-#endif

src/Rtcp/RtcpFCI.h

@@ -346,14 +346,16 @@ enum class SymbolStatus : uint8_t{
 class FCI_TWCC{
 public:
     static size_t constexpr kSize = 8;
-
+    using TwccPacketStatus = map<uint16_t/*rtp ext seq*/, std::pair<SymbolStatus, int16_t/*recv delta,单位为250us*/> >;
     void check(size_t size);
     string dumpString(size_t total_size) const;
     uint16_t getBaseSeq() const;
     //单位64ms
     uint32_t getReferenceTime() const;
     uint16_t getPacketCount() const;
-    map<uint16_t/*rtp ext seq*/, std::pair<SymbolStatus, int16_t/*recv delta,单位为250us*/> > getPacketChunkList(size_t total_size) const;
+    TwccPacketStatus getPacketChunkList(size_t total_size) const;
+
+    static string create(uint32_t ref_time, uint8_t fb_pkt_count, TwccPacketStatus &status);
 
 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

tests/test_rtcp_fci.cpp

@@ -1,25 +0,0 @@
-/*
- * Copyright (c) 2016 The ZLToolKit project authors. All Rights Reserved.
- *
- * This file is part of ZLToolKit(https://github.com/xia-chu/ZLToolKit).
- *
- * 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 <iostream>
-#include "Util/logger.h"
-#include "Rtcp/RtcpFCI.h"
-using namespace std;
-using namespace toolkit;
-using namespace mediakit;
-
-extern void testFCI();
-
-int main() {
-    Logger::Instance().add(std::make_shared<ConsoleChannel>());
-
-    testFCI();
-    return 0;
-}

webrtc/TwccContext.cpp

@@ -9,6 +9,9 @@
  */
 
 #include "TwccContext.h"
+#include "Rtcp/RtcpFCI.h"
+
+using namespace mediakit;
 
 enum class ExtSeqStatus : int {
     normal = 0,
@@ -78,17 +81,27 @@ void TwccContext::onSendTwcc() {
     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
+    FCI_TWCC::TwccPacketStatus status;
-           << ", fb count:" << (int) (_twcc_pkt_count++);
+    for (auto seq = min; seq <= max; ++seq) {
-    for (auto i = min; i <= max; ++i) {
+        int16_t delta = 0;
-        auto it = _rtp_recv_status.find(i);
+        SymbolStatus symbol = SymbolStatus::not_received;
-        if (it == _rtp_recv_status.end()) {
+        auto it = _rtp_recv_status.find(seq);
-            DebugL << "rtp seq:" << i << ",packet status:" << 0 /*not recved*/ << ",delta_ms:" << 0;
+        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));
+            if (delta < 0 || delta > 0xFF) {
+                symbol = SymbolStatus::large_delta;
             } else {
-            auto delta_ms = it->second - ref_time;
+                symbol = SymbolStatus::small_delta;
-            DebugL << "rtp seq:" << i << ",packet status:" << 1 /*recved*/ << ",delta_ms:" << delta_ms;
             }
+            ref_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;
     clearStatus();
 }