Implementation for FEC encoder module

src/fec/fec_encoder.cpp

@@ -0,0 +1,149 @@
+#include "fec_encoder.h"
+
+#include "log.h"
+
+FecEncoder::FecEncoder() {}
+
+FecEncoder::~FecEncoder() {}
+
+int FecEncoder::Init() {
+  fec_codec_id_ = OF_CODEC_REED_SOLOMON_GF_2_M_STABLE;
+
+  fec_rs_params_ = (of_rs_2_m_parameters_t *)calloc(1, sizeof(*fec_params_));
+  if (nullptr == fec_rs_params_) {
+    LOG_ERROR("Create FEC codec params failed");
+    return -1;
+  }
+
+  fec_rs_params_->m = 8;
+  fec_params_ = (of_parameters_t *)fec_rs_params_;
+
+  if (OF_STATUS_OK !=
+      of_create_codec_instance(&fec_session_, fec_codec_id_, OF_ENCODER, 2)) {
+    LOG_ERROR("Create FEC codec instance failed");
+    return -1;
+  }
+
+  return 0;
+}
+
+int FecEncoder::Release() {
+  if (!fec_session_) {
+    LOG_ERROR("Invalid FEC codec instance");
+    return -1;
+  }
+
+  {
+    if (OF_STATUS_OK != of_release_codec_instance(fec_session_)) {
+      LOG_ERROR("Release FEC codec instance failed");
+      return -1;
+    }
+  }
+
+  return 0;
+}
+
+uint8_t **FecEncoder::Encode(const char *data, size_t len) {
+  uint8_t **fec_packets = nullptr;
+
+  unsigned int last_packet_size = len % max_size_of_packet_;
+  unsigned int num_of_source_packets =
+      len / max_size_of_packet_ + (last_packet_size ? 1 : 0);
+  unsigned int num_of_total_packets =
+      (unsigned int)floor((double)num_of_source_packets / code_rate_);
+
+  fec_params_->nb_source_symbols = num_of_source_packets;
+  fec_params_->nb_repair_symbols = num_of_total_packets - num_of_source_packets;
+
+  fec_params_->encoding_symbol_length = max_size_of_packet_;
+
+  if (OF_STATUS_OK != of_set_fec_parameters(fec_session_, fec_params_)) {
+    LOG_ERROR("Set FEC params failed for codec_id {}", fec_codec_id_);
+    return nullptr;
+  }
+
+  fec_packets = (uint8_t **)calloc(num_of_total_packets, sizeof(uint8_t *));
+
+  if (nullptr == fec_packets) {
+    LOG_ERROR("Calloc failed for fec_packets with size [{}])",
+              num_of_total_packets);
+    return nullptr;
+  }
+
+  for (unsigned int esi = 0; esi < num_of_source_packets; esi++) {
+    if (esi != num_of_source_packets - 1) {
+      fec_packets[esi] =
+          (uint8_t *)calloc(max_size_of_packet_, sizeof(uint8_t));
+      if (nullptr == fec_packets[esi]) {
+        LOG_ERROR("Calloc failed for fec_packets[{}] with size [{}])", esi,
+                  max_size_of_packet_);
+        ReleaseFecPackets(fec_packets, len);
+        return nullptr;
+      }
+      memcpy(fec_packets[esi], data + esi * max_size_of_packet_,
+             max_size_of_packet_);
+    } else {
+      fec_packets[esi] =
+          (uint8_t *)calloc(max_size_of_packet_, sizeof(uint8_t));
+      if (nullptr == fec_packets[esi]) {
+        LOG_ERROR("Calloc failed for fec_packets[{}] with size [{}])", esi,
+                  last_packet_size);
+        ReleaseFecPackets(fec_packets, len);
+        return nullptr;
+      }
+      memcpy(fec_packets[esi], data + esi * max_size_of_packet_,
+             last_packet_size);
+    }
+  }
+
+  for (unsigned int esi = num_of_source_packets; esi < num_of_total_packets;
+       esi++) {
+    fec_packets[esi] = (uint8_t *)calloc(max_size_of_packet_, sizeof(uint8_t));
+    if (nullptr == fec_packets[esi]) {
+      LOG_ERROR("Calloc failed for fec_packets[{}] with size [{}])", esi,
+                max_size_of_packet_);
+      ReleaseFecPackets(fec_packets, len);
+      return nullptr;
+    }
+    if (OF_STATUS_OK !=
+        of_build_repair_symbol(fec_session_, (void **)fec_packets, esi)) {
+      LOG_ERROR("Build repair symbols failed for esi [{}]", esi);
+      ReleaseFecPackets(fec_packets, len);
+      return nullptr;
+    }
+  }
+
+  return fec_packets;
+}
+
+int FecEncoder::ReleaseFecPackets(uint8_t **fec_packets, size_t len) {
+  if (nullptr == fec_packets) {
+    LOG_ERROR("Release Fec packets failed, due to fec_packets is nullptr");
+    return -1;
+  }
+  unsigned int last_packet_size = len % max_size_of_packet_;
+  unsigned int num_of_source_packets =
+      len / max_size_of_packet_ + (last_packet_size ? 1 : 0);
+  unsigned int num_of_total_packets =
+      (unsigned int)floor((double)num_of_source_packets / code_rate_);
+
+  for (unsigned int esi = 0; esi < num_of_total_packets; esi++) {
+    if (fec_packets[esi]) {
+      free(fec_packets[esi]);
+    }
+  }
+  free(fec_packets);
+
+  return 0;
+}
+
+void FecEncoder::GetFecPacketsParams(unsigned int source_length,
+                                     unsigned int &num_of_total_packets,
+                                     unsigned int &num_of_source_packets,
+                                     unsigned int &last_packet_size) {
+  last_packet_size = source_length % max_size_of_packet_;
+  num_of_source_packets =
+      source_length / max_size_of_packet_ + (last_packet_size ? 1 : 0);
+  num_of_total_packets =
+      (unsigned int)floor((double)num_of_source_packets / code_rate_);
+}

src/fec/fec_encoder.h

@@ -0,0 +1,49 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2023-11-13
+ * Copyright (c) 2023 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _FEC_ENCODER_H_
+#define _FEC_ENCODER_H_
+
+#include <stdint.h>
+
+#include <vector>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+#include "lib_common/of_openfec_api.h"
+#ifdef __cplusplus
+};
+#endif
+
+class FecEncoder {
+ public:
+  FecEncoder();
+  ~FecEncoder();
+
+ public:
+  int Init();
+  int Release();
+  uint8_t **Encode(const char *data, size_t len);
+  int ReleaseFecPackets(uint8_t **fec_packets, size_t len);
+  void GetFecPacketsParams(unsigned int source_length,
+                           unsigned int &num_of_total_packets,
+                           unsigned int &num_of_source_packets,
+                           unsigned int &last_packet_size);
+
+ private:
+  double code_rate_ = 0.667;
+  int max_size_of_packet_ = 1400;
+
+ private:
+  of_codec_id_t fec_codec_id_ = OF_CODEC_REED_SOLOMON_GF_2_M_STABLE;
+  of_session_t *fec_session_ = nullptr;
+  of_parameters_t *fec_params_ = nullptr;
+  of_rs_2_m_parameters_t *fec_rs_params_ = nullptr;
+  of_ldpc_parameters_t *fec_ldpc_params_ = nullptr;
+};
+
+#endif

src/rtp/rtp_codec.cpp

@@ -14,7 +14,9 @@ RtpCodec ::RtpCodec(RtpPacket::PAYLOAD_TYPE payload_type)
       has_padding_(false),
       has_extension_(false),
       payload_type_(payload_type),
-      sequence_number_(0) {}
+      sequence_number_(0) {
+  fec_encoder_.Init();
+}
 
 RtpCodec ::~RtpCodec() {
   if (extension_data_) {
@@ -34,10 +36,71 @@ void RtpCodec::Encode(uint8_t* buffer, size_t size,
   //   rtp_packet_ = new RtpPacket();
   // }
 
-  RtpPacket rtp_packet;
-
   if (RtpPacket::PAYLOAD_TYPE::H264 == payload_type_) {
+    if (fec_enable_ && IsKeyFrame((const uint8_t*)buffer, size)) {
+      uint8_t** fec_packets = fec_encoder_.Encode((const char*)buffer, size);
+      if (nullptr == fec_packets) {
+        LOG_ERROR("Invalid fec_packets");
+        return;
+      }
+      unsigned int num_of_total_packets = 0;
+      unsigned int num_of_source_packets = 0;
+      unsigned int last_packet_size = 0;
+      fec_encoder_.GetFecPacketsParams(size, num_of_total_packets,
+                                       num_of_source_packets, last_packet_size);
+
+      for (size_t index = 0; index < num_of_total_packets; index++) {
+        RtpPacket rtp_packet;
+        rtp_packet.SetVerion(version_);
+        rtp_packet.SetHasPadding(has_padding_);
+        rtp_packet.SetHasExtension(has_extension_);
+        rtp_packet.SetMarker(index == num_of_total_packets ? 1 : 0);
+        rtp_packet.SetPayloadType(RtpPacket::PAYLOAD_TYPE(payload_type_));
+        rtp_packet.SetSequenceNumber(sequence_number_++);
+
+        timestamp_ = std::chrono::high_resolution_clock::now()
+                         .time_since_epoch()
+                         .count();
+        rtp_packet.SetTimestamp(timestamp_);
+        rtp_packet.SetSsrc(ssrc_);
+
+        if (!csrcs_.empty()) {
+          rtp_packet.SetCsrcs(csrcs_);
+        }
+
+        if (has_extension_) {
+          rtp_packet.SetExtensionProfile(extension_profile_);
+          rtp_packet.SetExtensionData(extension_data_, extension_len_);
+        }
+
+        RtpPacket::FU_INDICATOR fu_indicator;
+        fu_indicator.forbidden_bit = 0;
+        fu_indicator.nal_reference_idc = 0;
+        fu_indicator.nal_unit_type = FU_A;
+
+        RtpPacket::FU_HEADER fu_header;
+        fu_header.start = index == 0 ? 1 : 0;
+        fu_header.end = index == num_of_total_packets - 1 ? 1 : 0;
+        fu_header.remain_bit = 0;
+        fu_header.nal_unit_type = FU_A;
+
+        rtp_packet.SetFuIndicator(fu_indicator);
+        rtp_packet.SetFuHeader(fu_header);
+
+        if (index == num_of_source_packets - 1 && last_packet_size > 0) {
+          rtp_packet.EncodeH264Fua(fec_packets[index], last_packet_size);
+        } else {
+          rtp_packet.EncodeH264Fua(fec_packets[index], MAX_NALU_LEN);
+        }
+        packets.emplace_back(rtp_packet);
+      }
+
+      fec_encoder_.ReleaseFecPackets(fec_packets, size);
+      return;
+    }
+
     if (size <= MAX_NALU_LEN) {
+      RtpPacket rtp_packet;
       rtp_packet.SetVerion(version_);
       rtp_packet.SetHasPadding(has_padding_);
       rtp_packet.SetHasExtension(has_extension_);
@@ -73,6 +136,7 @@ void RtpCodec::Encode(uint8_t* buffer, size_t size,
       size_t packet_num = size / MAX_NALU_LEN + (last_packet_size ? 1 : 0);
 
       for (size_t index = 0; index < packet_num; index++) {
+        RtpPacket rtp_packet;
         rtp_packet.SetVerion(version_);
         rtp_packet.SetHasPadding(has_padding_);
         rtp_packet.SetHasExtension(has_extension_);
@@ -119,6 +183,7 @@ void RtpCodec::Encode(uint8_t* buffer, size_t size,
       }
     }
   } else if (RtpPacket::PAYLOAD_TYPE::DATA == payload_type_) {
+    RtpPacket rtp_packet;
     rtp_packet.SetVerion(version_);
     rtp_packet.SetHasPadding(has_padding_);
     rtp_packet.SetHasExtension(has_extension_);
@@ -157,3 +222,10 @@ size_t RtpCodec::Decode(RtpPacket& packet, uint8_t* payload) {
     return packet.DecodeData(payload);
   }
 }
+
+bool RtpCodec::IsKeyFrame(const uint8_t* buffer, size_t size) {
+  if (buffer != nullptr && size != 0 && (*(buffer + 4) & 0x1f) == 0x07) {
+    return true;
+  }
+  return false;
+}

src/rtp/rtp_codec.h

@@ -5,6 +5,7 @@
 
 #include <vector>
 
+#include "fec_encoder.h"
 #include "rtp_packet.h"
 
 class RtpCodec {
@@ -18,6 +19,8 @@ class RtpCodec {
 
   //  protected:
   //   void OnReceiveFrame(uint8_t* payload) = 0;
+ private:
+  bool IsKeyFrame(const uint8_t* buffer, size_t size);
 
  private:
   uint32_t version_ = 0;
@@ -38,6 +41,8 @@ class RtpCodec {
  private:
   // RtpPacket* rtp_packet_ = nullptr;
   RtpPacket::FU_INDICATOR fu_indicator_;
+  bool fec_enable_ = true;
+  FecEncoder fec_encoder_;
 };
 
 #endif

xmake.lua

@@ -26,14 +26,13 @@ elseif is_os("macosx") then
     add_ldflags("-ld_classic", {force = true})
 end
 
-add_requires("asio 1.24.0", "nlohmann_json", "spdlog 1.11.0")
+add_requires("asio 1.24.0", "nlohmann_json", "spdlog 1.11.0", "openfec")
-add_packages("spdlog")
+add_packages("spdlog", "openfec")
 includes("thirdparty")
 
 if has_config("server_only") then
     includes("application/signal_server")
 else
-    add_requires("openfec")
     if is_os("windows") then
         add_requires("vcpkg::ffmpeg 5.1.2", {configs = {shared = false}})
         add_requires("vcpkg::libnice 0.1.21")
@@ -84,6 +83,12 @@ else
         add_files("src/frame/*.cpp")
         add_includedirs("src/frame", {public = true})
 
+    target("fec")
+        set_kind("static")
+        add_deps("log")
+        add_files("src/fec/*.cpp")
+        add_includedirs("src/fec", {public = true})
+
     target("rtcp")
         set_kind("static")
         add_deps("log")
@@ -92,7 +97,7 @@ else
 
     target("rtp")
         set_kind("static")
-        add_deps("log", "frame", "ringbuffer", "thread", "rtcp")
+        add_deps("log", "frame", "ringbuffer", "thread", "rtcp", "fec")
         add_files("src/rtp/*.cpp")
         add_includedirs("src/rtp", {public = true})