From 6070654860a2ceaddaa348bb8895ddfe3f8927be Mon Sep 17 00:00:00 2001
From: xiongziliang <771730766@qq.com>
Date: Sun, 4 Apr 2021 23:58:59 +0800
Subject: [PATCH] =?UTF-8?q?rtc=E6=92=AD=E6=94=BE=E6=97=B6=EF=BC=8C?=
 =?UTF-8?q?=E6=AF=94=E5=AF=B9=E9=87=87=E6=A0=B7=E7=8E=87=E7=AD=89=E4=BF=A1?=
 =?UTF-8?q?=E6=81=AF?=
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---
 webrtc/Sdp.cpp             | 47 +++++++++++++++++++++++++++++++++-----
 webrtc/Sdp.h               |  9 +++++++-
 webrtc/WebRtcTransport.cpp |  7 ++++--
 3 files changed, 54 insertions(+), 9 deletions(-)

diff --git a/webrtc/Sdp.cpp b/webrtc/Sdp.cpp
index f83b2b7e..91d822bf 100644
--- a/webrtc/Sdp.cpp
+++ b/webrtc/Sdp.cpp
@@ -1331,6 +1331,10 @@ void RtcConfigure::matchMedia(shared_ptr<RtcSession> &ret, TrackType type, const
     if (!configure.enable) {
         return;
     }
+    bool failed = false;
+
+RETRY:
+
     for (auto &codec : configure.preferred_codec) {
         for (auto &offer_media : medias) {
             if (offer_media.type != type) {
@@ -1342,12 +1346,15 @@ void RtcConfigure::matchMedia(shared_ptr<RtcSession> &ret, TrackType type, const
             }
             const RtcCodecPlan *offer_plan_ptr = nullptr;
             for (auto &plan : offer_media.plan) {
-                if (getCodecId(plan.codec) != codec) {
-                    continue;
-                }
-                //命中偏好的编码格式
-                if (!onMatchCodecPlan(plan, codec)) {
-                    continue;
+                if (!failed) {
+                    //如果匹配失败了，那么随便选择一个plan
+                    if (getCodecId(plan.codec) != codec) {
+                        continue;
+                    }
+                    //命中偏好的编码格式
+                    if (!onMatchCodecPlan(plan, codec)) {
+                        continue;
+                    }
                 }
                 //找到中意的codec
                 offer_plan_ptr = &plan;
@@ -1476,4 +1483,32 @@ void RtcConfigure::matchMedia(shared_ptr<RtcSession> &ret, TrackType type, const
             return;
         }
     }
+
+    if (!failed) {
+        //只重试一次
+        failed = true;
+        goto RETRY;
+    }
+}
+
+void RtcConfigure::setPlayRtspInfo(const string &sdp){
+    RtcSession session;
+    session.loadFrom(sdp, false);
+    for (auto &m : session.media) {
+        switch (m.type) {
+            case TrackVideo : _rtsp_video_plan = std::make_shared<RtcCodecPlan>(m.plan[0]); break;
+            case TrackAudio : _rtsp_audio_plan = std::make_shared<RtcCodecPlan>(m.plan[0]); break;
+            default: break;
+        }
+    }
+}
+
+bool RtcConfigure::onMatchCodecPlan(const RtcCodecPlan &plan, CodecId codec){
+    if (_rtsp_audio_plan && codec == getCodecId(_rtsp_audio_plan->codec)) {
+        if (plan.sample_rate != _rtsp_audio_plan->sample_rate || plan.channel != _rtsp_audio_plan->channel) {
+            //音频采样率和通道数必须相同
+            return false;
+        }
+    }
+    return true;
 }
diff --git a/webrtc/Sdp.h b/webrtc/Sdp.h
index 0d0f972a..e7ba518e 100644
--- a/webrtc/Sdp.h
+++ b/webrtc/Sdp.h
@@ -574,6 +574,7 @@ public:
 //rtc传输编码方案
 class RtcCodecPlan{
 public:
+    using Ptr = shared_ptr<RtcCodecPlan>;
     uint8_t pt;
     string codec;
     uint32_t sample_rate;
@@ -702,9 +703,15 @@ public:
 
     shared_ptr<RtcSession> createAnswer(const RtcSession &offer);
 
+    void setPlayRtspInfo(const string &sdp);
+
 private:
     void matchMedia(shared_ptr<RtcSession> &ret, TrackType type, const vector<RtcMedia> &medias, const RtcTrackConfigure &configure);
-    bool onMatchCodecPlan(const RtcCodecPlan &plan, CodecId codec) { return true; }
+    bool onMatchCodecPlan(const RtcCodecPlan &plan, CodecId codec);
+
+private:
+    RtcCodecPlan::Ptr _rtsp_video_plan;
+    RtcCodecPlan::Ptr _rtsp_audio_plan;
 };
 
 
diff --git a/webrtc/WebRtcTransport.cpp b/webrtc/WebRtcTransport.cpp
index 0e32859b..7aa6417b 100644
--- a/webrtc/WebRtcTransport.cpp
+++ b/webrtc/WebRtcTransport.cpp
@@ -324,16 +324,19 @@ void WebRtcTransportImp::onRtcConfigure(RtcConfigure &configure) const {
         //这是播放
         configure.video.direction = RtpDirection::sendonly;
         configure.audio.direction = RtpDirection::sendonly;
+        configure.setPlayRtspInfo(_src->getSdp());
         _rtsp_send_sdp.loadFrom(_src->getSdp(), false);
         //根据rtsp流的相关信息，设置rtc最佳编码
         for (auto &m : _rtsp_send_sdp.media) {
             switch (m.type) {
                 case TrackVideo: {
-                    configure.video.preferred_codec.insert(configure.video.preferred_codec.begin(), getCodecId(m.plan[0].codec));
+                    configure.video.preferred_codec.clear();
+                    configure.video.preferred_codec.emplace_back(getCodecId(m.plan[0].codec));
                     break;
                 }
                 case TrackAudio: {
-                    configure.audio.preferred_codec.insert(configure.audio.preferred_codec.begin(),getCodecId(m.plan[0].codec));
+                    configure.audio.preferred_codec.clear();
+                    configure.audio.preferred_codec.emplace_back(getCodecId(m.plan[0].codec));
                     break;
                 }
                 default: