/* * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ // This file contains structures for describing SSRCs from a media source such // as a MediaStreamTrack when it is sent across an RTP session. Multiple media // sources may be sent across the same RTP session, each of them will be // described by one StreamParams object // SsrcGroup is used to describe the relationship between the SSRCs that // are used for this media source. // E.x: Consider a source that is sent as 3 simulcast streams // Let the simulcast elements have SSRC 10, 20, 30. // Let each simulcast element use FEC and let the protection packets have // SSRC 11,21,31. // To describe this 4 SsrcGroups are needed, // StreamParams would then contain ssrc = {10,11,20,21,30,31} and // ssrc_groups = {{SIM,{10,20,30}, {FEC,{10,11}, {FEC, {20,21}, {FEC {30,31}}} // Please see RFC 5576. // A spec-compliant way to achieve this is to use RIDs and Simulcast attribute // instead of the ssrc-group. In this method, the StreamParam object will // have multiple RidDescriptions, each corresponding to a simulcast layer // and the media section will have a simulcast attribute that indicates // that these layers are for the same source. This also removes the extra // lines for redundancy streams, as the same RIDs appear in the redundancy // packets. // Note: in the spec compliant simulcast scenario, some of the RIDs might be // alternatives for one another (such as different encodings for same data). // In the context of the StreamParams class, the notion of alternatives does // not exist and all the RIDs will describe different layers of the same source. // When the StreamParams class is used to configure the media engine, simulcast // considerations will be used to remove the alternative layers outside of this // class. // As an example, let the simulcast layers have RID 10, 20, 30. // StreamParams would contain rid = { 10, 20, 30 }. // MediaSection would contain SimulcastDescription specifying these rids. // a=simulcast:send 10;20;30 (or a=simulcast:send 10,20;30 or similar). // See https://tools.ietf.org/html/draft-ietf-mmusic-sdp-simulcast-13 // and https://tools.ietf.org/html/draft-ietf-mmusic-rid-15. #ifndef MEDIA_BASE_STREAM_PARAMS_H_ #define MEDIA_BASE_STREAM_PARAMS_H_ #include #include #include #include #include "absl/algorithm/container.h" #include "media/base/rid_description.h" #include "rtc_base/unique_id_generator.h" namespace cricket { extern const char kFecSsrcGroupSemantics[]; extern const char kFecFrSsrcGroupSemantics[]; extern const char kFidSsrcGroupSemantics[]; extern const char kSimSsrcGroupSemantics[]; struct SsrcGroup { SsrcGroup(const std::string& usage, const std::vector& ssrcs); SsrcGroup(const SsrcGroup&); SsrcGroup(SsrcGroup&&); ~SsrcGroup(); SsrcGroup& operator=(const SsrcGroup&); SsrcGroup& operator=(SsrcGroup&&); bool operator==(const SsrcGroup& other) const { return (semantics == other.semantics && ssrcs == other.ssrcs); } bool operator!=(const SsrcGroup& other) const { return !(*this == other); } bool has_semantics(const std::string& semantics) const; std::string ToString() const; std::string semantics; // e.g FIX, FEC, SIM. std::vector ssrcs; // SSRCs of this type. }; // StreamParams is used to represent a sender/track in a SessionDescription. // In Plan B, this means that multiple StreamParams can exist within one // MediaContentDescription, while in UnifiedPlan this means that there is one // StreamParams per MediaContentDescription. struct StreamParams { StreamParams(); StreamParams(const StreamParams&); StreamParams(StreamParams&&); ~StreamParams(); StreamParams& operator=(const StreamParams&); StreamParams& operator=(StreamParams&&); static StreamParams CreateLegacy(uint32_t ssrc) { StreamParams stream; stream.ssrcs.push_back(ssrc); return stream; } bool operator==(const StreamParams& other) const; bool operator!=(const StreamParams& other) const { return !(*this == other); } uint32_t first_ssrc() const { if (ssrcs.empty()) { return 0; } return ssrcs[0]; } bool has_ssrcs() const { return !ssrcs.empty(); } bool has_ssrc(uint32_t ssrc) const { return absl::c_linear_search(ssrcs, ssrc); } void add_ssrc(uint32_t ssrc) { ssrcs.push_back(ssrc); } bool has_ssrc_groups() const { return !ssrc_groups.empty(); } bool has_ssrc_group(const std::string& semantics) const { return (get_ssrc_group(semantics) != NULL); } const SsrcGroup* get_ssrc_group(const std::string& semantics) const { for (const SsrcGroup& ssrc_group : ssrc_groups) { if (ssrc_group.has_semantics(semantics)) { return &ssrc_group; } } return NULL; } // Convenience function to add an FID ssrc for a primary_ssrc // that's already been added. bool AddFidSsrc(uint32_t primary_ssrc, uint32_t fid_ssrc) { return AddSecondarySsrc(kFidSsrcGroupSemantics, primary_ssrc, fid_ssrc); } // Convenience function to lookup the FID ssrc for a primary_ssrc. // Returns false if primary_ssrc not found or FID not defined for it. bool GetFidSsrc(uint32_t primary_ssrc, uint32_t* fid_ssrc) const { return GetSecondarySsrc(kFidSsrcGroupSemantics, primary_ssrc, fid_ssrc); } // Convenience function to add an FEC-FR ssrc for a primary_ssrc // that's already been added. bool AddFecFrSsrc(uint32_t primary_ssrc, uint32_t fecfr_ssrc) { return AddSecondarySsrc(kFecFrSsrcGroupSemantics, primary_ssrc, fecfr_ssrc); } // Convenience function to lookup the FEC-FR ssrc for a primary_ssrc. // Returns false if primary_ssrc not found or FEC-FR not defined for it. bool GetFecFrSsrc(uint32_t primary_ssrc, uint32_t* fecfr_ssrc) const { return GetSecondarySsrc(kFecFrSsrcGroupSemantics, primary_ssrc, fecfr_ssrc); } // Convenience function to populate the StreamParams with the requested number // of SSRCs along with accompanying FID and FEC-FR ssrcs if requested. // SSRCs are generated using the given generator. void GenerateSsrcs(int num_layers, bool generate_fid, bool generate_fec_fr, rtc::UniqueRandomIdGenerator* ssrc_generator); // Convenience to get all the SIM SSRCs if there are SIM ssrcs, or // the first SSRC otherwise. void GetPrimarySsrcs(std::vector* ssrcs) const; // Convenience to get all the FID SSRCs for the given primary ssrcs. // If a given primary SSRC does not have a FID SSRC, the list of FID // SSRCS will be smaller than the list of primary SSRCs. void GetFidSsrcs(const std::vector& primary_ssrcs, std::vector* fid_ssrcs) const; // Stream ids serialized to SDP. std::vector stream_ids() const; void set_stream_ids(const std::vector& stream_ids); // Returns the first stream id or "" if none exist. This method exists only // as temporary backwards compatibility with the old sync_label. std::string first_stream_id() const; std::string ToString() const; // A unique identifier of the StreamParams object. When the SDP is created, // this comes from the track ID of the sender that the StreamParams object // is associated with. std::string id; // There may be no SSRCs stored in unsignaled case when stream_ids are // signaled with a=msid lines. std::vector ssrcs; // All SSRCs for this source std::vector ssrc_groups; // e.g. FID, FEC, SIM std::string cname; // RTCP CNAME // RID functionality according to // https://tools.ietf.org/html/draft-ietf-mmusic-rid-15 // Each layer can be represented by a RID identifier and can also have // restrictions (such as max-width, max-height, etc.) // If the track has multiple layers (ex. Simulcast), each layer will be // represented by a RID. bool has_rids() const { return !rids_.empty(); } const std::vector& rids() const { return rids_; } void set_rids(const std::vector& rids) { rids_ = rids; } private: bool AddSecondarySsrc(const std::string& semantics, uint32_t primary_ssrc, uint32_t secondary_ssrc); bool GetSecondarySsrc(const std::string& semantics, uint32_t primary_ssrc, uint32_t* secondary_ssrc) const; // The stream IDs of the sender that the StreamParams object is associated // with. In Plan B this should always be size of 1, while in Unified Plan this // could be none or multiple stream IDs. std::vector stream_ids_; std::vector rids_; }; // A Stream can be selected by either id or ssrc. struct StreamSelector { explicit StreamSelector(uint32_t ssrc) : ssrc(ssrc) {} explicit StreamSelector(const std::string& streamid) : ssrc(0), streamid(streamid) {} bool Matches(const StreamParams& stream) const { if (ssrc == 0) { return stream.id == streamid; } else { return stream.has_ssrc(ssrc); } } uint32_t ssrc; std::string streamid; }; typedef std::vector StreamParamsVec; template const StreamParams* GetStream(const StreamParamsVec& streams, Condition condition) { auto found = absl::c_find_if(streams, condition); return found == streams.end() ? nullptr : &(*found); } template StreamParams* GetStream(StreamParamsVec& streams, Condition condition) { auto found = absl::c_find_if(streams, condition); return found == streams.end() ? nullptr : &(*found); } inline bool HasStreamWithNoSsrcs(const StreamParamsVec& streams) { return GetStream(streams, [](const StreamParams& sp) { return !sp.has_ssrcs(); }); } inline const StreamParams* GetStreamBySsrc(const StreamParamsVec& streams, uint32_t ssrc) { return GetStream( streams, [&ssrc](const StreamParams& sp) { return sp.has_ssrc(ssrc); }); } inline const StreamParams* GetStreamByIds(const StreamParamsVec& streams, const std::string& id) { return GetStream(streams, [&id](const StreamParams& sp) { return sp.id == id; }); } inline StreamParams* GetStreamByIds(StreamParamsVec& streams, const std::string& id) { return GetStream(streams, [&id](const StreamParams& sp) { return sp.id == id; }); } inline const StreamParams* GetStream(const StreamParamsVec& streams, const StreamSelector& selector) { return GetStream(streams, [&selector](const StreamParams& sp) { return selector.Matches(sp); }); } template bool RemoveStream(StreamParamsVec* streams, Condition condition) { auto iter(std::remove_if(streams->begin(), streams->end(), condition)); if (iter == streams->end()) return false; streams->erase(iter, streams->end()); return true; } // Removes the stream from streams. Returns true if a stream is // found and removed. inline bool RemoveStream(StreamParamsVec* streams, const StreamSelector& selector) { return RemoveStream(streams, [&selector](const StreamParams& sp) { return selector.Matches(sp); }); } inline bool RemoveStreamBySsrc(StreamParamsVec* streams, uint32_t ssrc) { return RemoveStream( streams, [&ssrc](const StreamParams& sp) { return sp.has_ssrc(ssrc); }); } inline bool RemoveStreamByIds(StreamParamsVec* streams, const std::string& id) { return RemoveStream(streams, [&id](const StreamParams& sp) { return sp.id == id; }); } } // namespace cricket #endif // MEDIA_BASE_STREAM_PARAMS_H_