From acbe99cb43418ef280ab44a109345f92c0e5d31f Mon Sep 17 00:00:00 2001 From: ziyue <1213642868@qq.com> Date: Tue, 12 Oct 2021 21:26:01 +0800 Subject: [PATCH] =?UTF-8?q?=E6=95=B4=E7=90=86=E4=BC=98=E5=8C=96webrtc=20ss?= =?UTF-8?q?rc=E4=B8=8Esimulcast=E7=9B=B8=E5=85=B3=E4=BB=A3=E7=A0=81?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- webrtc/Sdp.cpp | 163 ++++++++++++++++++++++--------------- webrtc/Sdp.h | 2 + webrtc/WebRtcTransport.cpp | 5 +- 3 files changed, 103 insertions(+), 67 deletions(-) diff --git a/webrtc/Sdp.cpp b/webrtc/Sdp.cpp index 51e1c173..2e8010ee 100644 --- a/webrtc/Sdp.cpp +++ b/webrtc/Sdp.cpp @@ -870,57 +870,72 @@ void RtcSession::loadFrom(const string &str, bool check) { } auto ssrc_groups = media.getAllItem('a', "ssrc-group"); + bool have_rtx_ssrc = false; SdpAttrSSRCGroup *ssrc_group_sim = nullptr; - SdpAttrSSRCGroup *ssrc_group_fid = nullptr; for (auto &group : ssrc_groups) { if (group.isFID()) { - ssrc_group_fid = &group; + have_rtx_ssrc = true; + //ssrc-group:FID字段必须包含rtp/rtx的ssrc + CHECK(group.ssrcs.size() == 2); + //根据rtp ssrc找到对象 + auto it = rtc_ssrc_map.find(group.ssrcs[0]); + CHECK(it != rtc_ssrc_map.end()); + //设置rtx ssrc + it->second.rtx_ssrc = group.ssrcs[1]; + rtc_media.rtp_rtx_ssrc.emplace_back(it->second); } else if (group.isSIM()) { + CHECK(!ssrc_group_sim); ssrc_group_sim = &group; } } - if (ssrc_group_fid) { - //指定了ssrc-group:FID字段 - for (auto ssrc : ssrc_group_fid->ssrcs) { - auto it = rtc_ssrc_map.find(ssrc); - if (it == rtc_ssrc_map.end()) { - throw std::invalid_argument("a=ssrc-group:FID字段指定的ssrc未找到"); + if (!have_rtx_ssrc) { + //按照sdp顺序依次添加ssrc + for (auto &attr : ssrc_attr) { + if (attr.attribute == "cname") { + rtc_media.rtp_rtx_ssrc.emplace_back(rtc_ssrc_map[attr.ssrc]); } - rtc_media.rtp_rtx_ssrc.emplace_back(it->second); } - CHECK(rtc_media.rtp_rtx_ssrc.size() == 2); - } else { - auto simulcast = media.getItemClass('a', "simulcast"); - if (simulcast.empty()) { - //没有指定ssrc-group:FID字段,也不是simulcast，那么只有1个或0个ssrc - if (rtc_ssrc_map.size() == 1) { - rtc_media.rtp_rtx_ssrc.emplace_back(rtc_ssrc_map.begin()->second); - } else if (rtc_ssrc_map.size() > 1) { - throw std::invalid_argument("sdp中不存在a=ssrc-group:FID字段,但是ssrc却大于1个"); - } - } else { - //开启simulcast - rtc_media.rtp_rids = simulcast.rids; - //simulcast最少要求2种方案 - CHECK(rtc_media.rtp_rids.size() >= 2); + } + + auto simulcast = media.getItemClass('a', "simulcast"); + if (!simulcast.empty()) { + // a=rid:h send + // a=rid:m send + // a=rid:l send + // a=simulcast:send h;m;l + // 风格的simulcast + unordered_set rid_map; + for (auto &rid : simulcast.rids) { + rid_map.emplace(rid); } + for (auto &rid : media.getAllItem('a', "rid")) { + CHECK(rid.direction == simulcast.direction); + CHECK(rid_map.find(rid.rid) != rid_map.end()); + } + //simulcast最少要求2种方案 + CHECK(simulcast.rids.size() >= 2); + rtc_media.rtp_rids = simulcast.rids; } if (ssrc_group_sim) { //指定了a=ssrc-group:SIM for (auto ssrc : ssrc_group_sim->ssrcs) { auto it = rtc_ssrc_map.find(ssrc); - if (it == rtc_ssrc_map.end()) { - throw std::invalid_argument("a=ssrc-group:SIM字段指定的ssrc未找到"); - } + CHECK(it != rtc_ssrc_map.end()); rtc_media.rtp_ssrc_sim.emplace_back(it->second); } } else if (!rtc_media.rtp_rids.empty()) { - //未指定a=ssrc-group:SIM，但是指定了a=simulcast,且可能指定了ssrc - for (auto &attr : ssrc_attr) { - rtc_media.rtp_ssrc_sim.emplace_back(rtc_ssrc_map[attr.ssrc]); - } + //未指定a=ssrc-group:SIM, 但是指定了a=simulcast, 那么只能根据ssrc顺序来对应rid顺序 + rtc_media.rtp_ssrc_sim = rtc_media.rtp_rtx_ssrc; + } + + if (!rtc_media.supportSimulcast()) { + //不支持simulcast的情况下，最多一组ssrc + CHECK(rtc_media.rtp_rtx_ssrc.size() <= 1); + } else { + //simulcast的情况下，要么没有指定ssrc，要么指定的ssrc个数与rid个数一致 + CHECK(rtc_media.rtp_ssrc_sim.empty() || rtc_media.rtp_ssrc_sim.size() == rtc_media.rtp_rids.size()); } auto rtpmap_arr = media.getAllItem('a', "rtpmap"); @@ -1161,43 +1176,56 @@ RtcSessionSdp::Ptr RtcSession::toRtcSessionSdp() const{ static auto addSSRCItem = [](const RtcSSRC &rtp_ssrc, vector &items) { CHECK(!rtp_ssrc.empty()); - SdpAttrSSRC ssrc; - ssrc.ssrc = rtp_ssrc.ssrc; + auto ssrc_num = rtp_ssrc.ssrc; + for (auto i = 0; i < 2; ++i) { + SdpAttrSSRC ssrc; + ssrc.ssrc = ssrc_num; - ssrc.attribute = "cname"; - ssrc.attribute_value = rtp_ssrc.cname; - items.emplace_back(wrapSdpAttr(std::make_shared(ssrc))); - - if (!rtp_ssrc.msid.empty()) { - ssrc.attribute = "msid"; - ssrc.attribute_value = rtp_ssrc.msid; + ssrc.attribute = "cname"; + ssrc.attribute_value = rtp_ssrc.cname; items.emplace_back(wrapSdpAttr(std::make_shared(ssrc))); - } - if (!rtp_ssrc.mslabel.empty()) { - ssrc.attribute = "mslabel"; - ssrc.attribute_value = rtp_ssrc.mslabel; - items.emplace_back(wrapSdpAttr(std::make_shared(ssrc))); - } + if (!rtp_ssrc.msid.empty()) { + ssrc.attribute = "msid"; + ssrc.attribute_value = rtp_ssrc.msid; + items.emplace_back(wrapSdpAttr(std::make_shared(ssrc))); + } - if (!rtp_ssrc.label.empty()) { - ssrc.attribute = "label"; - ssrc.attribute_value = rtp_ssrc.label; - items.emplace_back(wrapSdpAttr(std::make_shared(ssrc))); + if (!rtp_ssrc.mslabel.empty()) { + ssrc.attribute = "mslabel"; + ssrc.attribute_value = rtp_ssrc.mslabel; + items.emplace_back(wrapSdpAttr(std::make_shared(ssrc))); + } + + if (!rtp_ssrc.label.empty()) { + ssrc.attribute = "label"; + ssrc.attribute_value = rtp_ssrc.label; + items.emplace_back(wrapSdpAttr(std::make_shared(ssrc))); + } + if (rtp_ssrc.rtx_ssrc) { + ssrc_num = rtp_ssrc.rtx_ssrc; + } else { + break; + } } }; { - auto group = std::make_shared(); for (auto &ssrc : m.rtp_rtx_ssrc) { //添加a=ssrc字段 addSSRCItem(ssrc, sdp_media.items); - group->ssrcs.emplace_back(ssrc.ssrc); } - if (group->ssrcs.size() >= 2) { - group->type = "FID"; + + for (auto &ssrc : m.rtp_rtx_ssrc) { //生成a=ssrc-group:FID字段 - sdp_media.items.emplace_back(wrapSdpAttr(std::move(group))); + if (ssrc.rtx_ssrc) { + //有rtx ssrc + auto group = std::make_shared(); + group->type = "FID"; + group->ssrcs.emplace_back(ssrc.ssrc); + group->ssrcs.emplace_back(ssrc.rtx_ssrc); + sdp_media.items.emplace_back(wrapSdpAttr(std::move(group))); + } } } @@ -1205,9 +1233,7 @@ RtcSessionSdp::Ptr RtcSession::toRtcSessionSdp() const{ if (m.rtp_ssrc_sim.size() >= 2) { //simulcast 要求 2~3路 auto group = std::make_shared(); - for (auto &ssrc : m.rtp_ssrc_sim) { - //添加simulcast的ssrc - addSSRCItem(ssrc, sdp_media.items); + for (auto &ssrc : m.rtp_ssrc_sim) { group->ssrcs.emplace_back(ssrc.ssrc); } //添加a=ssrc-group:SIM字段 @@ -1294,12 +1320,22 @@ uint32_t RtcMedia::getRtpSSRC() const { } uint32_t RtcMedia::getRtxSSRC() const { - if (rtp_rtx_ssrc.size() > 1) { - return rtp_rtx_ssrc[1].ssrc; + if (rtp_rtx_ssrc.size()) { + return rtp_rtx_ssrc[0].rtx_ssrc; } return 0; } +bool RtcMedia::supportSimulcast() const { + if (!rtp_rids.empty()) { + return true; + } + if (!rtp_ssrc_sim.empty()) { + return true; + } + return false; +} + void RtcMedia::checkValid() const{ CHECK(type != TrackInvalid); CHECK(!mid.empty()); @@ -1372,15 +1408,13 @@ bool RtcSession::supportRtcpFb(const string &name, TrackType type) const { bool RtcSession::supportSimulcast() const { for (auto &m : media) { - if (!m.rtp_rids.empty()) { - return true; - } - if (!m.rtp_ssrc_sim.empty()) { + if (m.supportSimulcast()) { return true; } } return false; } + void RtcSession::checkSdp() const { for (auto &m : media) { if (m.type != TrackApplication && !m.rtcp_mux) { @@ -1636,6 +1670,7 @@ RETRY: answer_media.candidate = configure.candidate; answer_media.rtp_rids = offer_media.rtp_rids; answer_media.rtp_ssrc_sim = offer_media.rtp_ssrc_sim; + answer_media.rtp_rtx_ssrc = offer_media.rtp_rtx_ssrc; switch (offer_media.role) { case DtlsRole::actpass : case DtlsRole::active : { diff --git a/webrtc/Sdp.h b/webrtc/Sdp.h index 1649d1a5..10c8b64f 100644 --- a/webrtc/Sdp.h +++ b/webrtc/Sdp.h @@ -573,6 +573,7 @@ public: class RtcSSRC{ public: uint32_t ssrc {0}; + uint32_t rtx_ssrc {0}; string cname; string msid; string mslabel; @@ -647,6 +648,7 @@ public: const RtcCodecPlan *getRelatedRtxPlan(uint8_t pt) const; uint32_t getRtpSSRC() const; uint32_t getRtxSSRC() const; + bool supportSimulcast() const; }; class RtcSession{ diff --git a/webrtc/WebRtcTransport.cpp b/webrtc/WebRtcTransport.cpp index afa1be95..f6b3a3df 100644 --- a/webrtc/WebRtcTransport.cpp +++ b/webrtc/WebRtcTransport.cpp @@ -539,9 +539,8 @@ void WebRtcTransportImp::onCheckAnswer(RtcSession &sdp) { m.rtp_rtx_ssrc[0].msid = RTP_MSID; if (m.getRelatedRtxPlan(m.plan[0].pt)) { - m.rtp_rtx_ssrc.emplace_back(); - m.rtp_rtx_ssrc[1] = m.rtp_rtx_ssrc[0]; - m.rtp_rtx_ssrc[1].ssrc += RTX_SSRC_OFFSET; + //rtx ssrc + m.rtp_rtx_ssrc[0].rtx_ssrc = m.rtp_rtx_ssrc[0].ssrc + RTX_SSRC_OFFSET; } } }