webrtc answer m-lines次序错误 (#1695)

Co-authored-by: james <mrjamesli@126.com>

webrtc/Sdp.cpp

@@ -1521,15 +1521,17 @@ void RtcConfigure::enableREMB(bool enable, TrackType type){
     }
 }
 
-shared_ptr<RtcSession> RtcConfigure::createAnswer(const RtcSession &offer){
+shared_ptr<RtcSession> RtcConfigure::createAnswer(const RtcSession &offer) const {
     shared_ptr<RtcSession> ret = std::make_shared<RtcSession>();
     ret->version = offer.version;
     ret->origin = offer.origin;
     ret->session_name = offer.session_name;
     ret->msid_semantic = offer.msid_semantic;
-    matchMedia(ret, TrackAudio, offer.media, audio);
-    matchMedia(ret, TrackVideo, offer.media, video);
-    matchMedia(ret, TrackApplication, offer.media, application);
+
+    for (auto &m : offer.media) {
+        matchMedia(ret, m);
+    }
+
     //设置音视频端口复用
     if (!offer.group.mids.empty()) {
         for (auto &m : ret->media) {
@@ -1573,17 +1575,22 @@ static DtlsRole mathDtlsRole(DtlsRole role){
     }
 }
 
-void RtcConfigure::matchMedia(const shared_ptr<RtcSession> &ret, TrackType type, const vector<RtcMedia> &medias, const RtcTrackConfigure &configure){
+void RtcConfigure::matchMedia(const std::shared_ptr<RtcSession> &ret,const RtcMedia &offer_media) const {
     bool check_profile = true;
     bool check_codec = true;
+    const RtcTrackConfigure *cfg_ptr = nullptr;
+
+    switch (offer_media.type) {
+        case TrackAudio: cfg_ptr = &audio; break;
+        case TrackVideo: cfg_ptr = &video; break;
+        case TrackApplication: cfg_ptr = &application; break;
+        default: return;
+    }
+    auto &configure = *cfg_ptr;
 
 RETRY:
 
-    for (auto &offer_media : medias) {
-        if (offer_media.type != type) {
-            continue;
-        }
-        if (type == TrackApplication) {
+    if (offer_media.type == TrackApplication) {
         RtcMedia answer_media = offer_media;
         answer_media.role = mathDtlsRole(offer_media.role);
 #ifdef ENABLE_SCTP
@@ -1720,7 +1727,6 @@ RETRY:
         ret->media.emplace_back(answer_media);
         return;
     }
-    }
 
     if (check_profile) {
         //如果是由于检查profile导致匹配失败，那么重试一次，且不检查profile
@@ -1765,7 +1771,7 @@ void RtcConfigure::setPlayRtspInfo(const string &sdp){
 static const string kProfile{"profile-level-id"};
 static const string kMode{"packetization-mode"};
 
-bool RtcConfigure::onCheckCodecProfile(const RtcCodecPlan &plan, CodecId codec){
+bool RtcConfigure::onCheckCodecProfile(const RtcCodecPlan &plan, CodecId codec) const {
     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
@@ -1785,7 +1791,7 @@ bool RtcConfigure::onCheckCodecProfile(const RtcCodecPlan &plan, CodecId codec){
     return true;
 }
 
-void RtcConfigure::onSelectPlan(RtcCodecPlan &plan, CodecId codec){
+void RtcConfigure::onSelectPlan(RtcCodecPlan &plan, CodecId codec) const {
     if (_rtsp_video_plan && codec == CodecH264 && getCodecId(_rtsp_video_plan->codec) == CodecH264) {
         //h264时，设置packetization-mod为一致
         auto mode = _rtsp_video_plan->fmtp[kMode];

webrtc/Sdp.h

@@ -720,7 +720,7 @@ public:
     void setDefaultSetting(std::string ice_ufrag, std::string ice_pwd, RtpDirection direction, const SdpAttrFingerprint &fingerprint);
     void addCandidate(const SdpAttrCandidate &candidate, mediakit::TrackType type = mediakit::TrackInvalid);
 
-    std::shared_ptr<RtcSession> createAnswer(const RtcSession &offer);
+    std::shared_ptr<RtcSession> createAnswer(const RtcSession &offer) const;
 
     void setPlayRtspInfo(const std::string &sdp);
 
@@ -728,9 +728,9 @@ public:
     void enableREMB(bool enable = true, mediakit::TrackType type = mediakit::TrackInvalid);
 
 private:
-    void matchMedia(const std::shared_ptr<RtcSession> &ret, mediakit::TrackType type, const std::vector<RtcMedia> &medias, const RtcTrackConfigure &configure);
-    bool onCheckCodecProfile(const RtcCodecPlan &plan, mediakit::CodecId codec);
-    void onSelectPlan(RtcCodecPlan &plan, mediakit::CodecId codec);
+    void matchMedia(const std::shared_ptr<RtcSession> &ret, const RtcMedia &media) const;
+    bool onCheckCodecProfile(const RtcCodecPlan &plan, mediakit::CodecId codec) const;
+    void onSelectPlan(RtcCodecPlan &plan, mediakit::CodecId codec) const;
 
 private:
     RtcCodecPlan::Ptr _rtsp_video_plan;