| /* |
| * Copyright 2025 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. |
| */ |
| #include "pc/codec_vendor.h" |
| |
| #include <stddef.h> |
| |
| #include <algorithm> |
| #include <map> |
| #include <optional> |
| #include <string> |
| #include <unordered_map> |
| #include <utility> |
| #include <vector> |
| |
| #include "absl/algorithm/container.h" |
| #include "absl/strings/match.h" |
| #include "absl/strings/string_view.h" |
| #include "api/field_trials_view.h" |
| #include "api/media_types.h" |
| #include "api/rtc_error.h" |
| #include "api/rtp_parameters.h" |
| #include "api/rtp_transceiver_direction.h" |
| #include "call/payload_type.h" |
| #include "media/base/codec.h" |
| #include "media/base/codec_comparators.h" |
| #include "media/base/codec_list.h" |
| #include "media/base/media_constants.h" |
| #include "media/base/media_engine.h" |
| #include "media/base/sdp_video_format_utils.h" |
| #include "pc/media_options.h" |
| #include "pc/rtp_media_utils.h" |
| #include "pc/session_description.h" |
| #include "pc/typed_codec_vendor.h" |
| #include "pc/used_ids.h" |
| #include "rtc_base/checks.h" |
| #include "rtc_base/logging.h" |
| #include "rtc_base/string_encode.h" |
| #include "rtc_base/strings/string_builder.h" |
| #include "rtc_base/unique_id_generator.h" |
| |
| #ifdef RTC_ENABLE_H265 |
| #include "api/video_codecs/h265_profile_tier_level.h" |
| #endif |
| |
| namespace cricket { |
| |
| namespace { |
| |
| using rtc::UniqueRandomIdGenerator; |
| using webrtc::PayloadTypeSuggester; |
| using webrtc::RTCError; |
| using webrtc::RTCErrorOr; |
| using webrtc::RTCErrorType; |
| using webrtc::RtpTransceiverDirection; |
| |
| bool IsRtxCodec(const webrtc::RtpCodecCapability& capability) { |
| return absl::EqualsIgnoreCase(capability.name, kRtxCodecName); |
| } |
| |
| bool IsRedCodec(const webrtc::RtpCodecCapability& capability) { |
| return absl::EqualsIgnoreCase(capability.name, kRedCodecName); |
| } |
| |
| bool IsComfortNoiseCodec(const Codec& codec) { |
| return absl::EqualsIgnoreCase(codec.name, kComfortNoiseCodecName); |
| } |
| |
| // Wrapper for FindMatchingCodecs that uses CodecList |
| std::optional<Codec> FindMatchingCodec(const CodecList& codecs1, |
| const CodecList& codecs2, |
| const Codec& codec_to_match) { |
| return webrtc::FindMatchingCodec(codecs1.codecs(), codecs2.codecs(), |
| codec_to_match); |
| } |
| |
| void StripCNCodecs(CodecList& audio_codecs) { |
| audio_codecs.writable_codecs().erase( |
| std::remove_if( |
| audio_codecs.begin(), audio_codecs.end(), |
| [](const Codec& codec) { return IsComfortNoiseCodec(codec); }), |
| audio_codecs.end()); |
| } |
| |
| bool IsMediaContentOfType(const ContentInfo* content, MediaType media_type) { |
| if (!content || !content->media_description()) { |
| return false; |
| } |
| return content->media_description()->type() == media_type; |
| } |
| // Find the codec in `codec_list` that `rtx_codec` is associated with. |
| const Codec* GetAssociatedCodecForRtx(const CodecList& codec_list, |
| const Codec& rtx_codec) { |
| std::string associated_pt_str; |
| if (!rtx_codec.GetParam(kCodecParamAssociatedPayloadType, |
| &associated_pt_str)) { |
| RTC_LOG(LS_WARNING) << "RTX codec " << rtx_codec.id |
| << " is missing an associated payload type."; |
| return nullptr; |
| } |
| |
| int associated_pt; |
| if (!rtc::FromString(associated_pt_str, &associated_pt)) { |
| RTC_LOG(LS_WARNING) << "Couldn't convert payload type " << associated_pt_str |
| << " of RTX codec " << rtx_codec.id |
| << " to an integer."; |
| return nullptr; |
| } |
| |
| // Find the associated codec for the RTX codec. |
| const Codec* associated_codec = |
| FindCodecById(codec_list.codecs(), associated_pt); |
| if (!associated_codec) { |
| RTC_LOG(LS_WARNING) << "Couldn't find associated codec with payload type " |
| << associated_pt << " for RTX codec " << rtx_codec.id |
| << "."; |
| } |
| return associated_codec; |
| } |
| |
| // Find the codec in `codec_list` that `red_codec` is associated with. |
| const Codec* GetAssociatedCodecForRed(const CodecList& codec_list, |
| const Codec& red_codec) { |
| std::string fmtp; |
| if (!red_codec.GetParam(kCodecParamNotInNameValueFormat, &fmtp)) { |
| // Don't log for video/RED where this is normal. |
| if (red_codec.type == Codec::Type::kAudio) { |
| RTC_LOG(LS_WARNING) << "RED codec " << red_codec.id |
| << " is missing an associated payload type."; |
| } |
| return nullptr; |
| } |
| |
| std::vector<absl::string_view> redundant_payloads = rtc::split(fmtp, '/'); |
| if (redundant_payloads.size() < 2) { |
| return nullptr; |
| } |
| |
| absl::string_view associated_pt_str = redundant_payloads[0]; |
| int associated_pt; |
| if (!rtc::FromString(associated_pt_str, &associated_pt)) { |
| RTC_LOG(LS_WARNING) << "Couldn't convert first payload type " |
| << associated_pt_str << " of RED codec " << red_codec.id |
| << " to an integer."; |
| return nullptr; |
| } |
| |
| // Find the associated codec for the RED codec. |
| const Codec* associated_codec = |
| FindCodecById(codec_list.codecs(), associated_pt); |
| if (!associated_codec) { |
| RTC_LOG(LS_WARNING) << "Couldn't find associated codec with payload type " |
| << associated_pt << " for RED codec " << red_codec.id |
| << "."; |
| } |
| return associated_codec; |
| } |
| |
| // Adds all codecs from `reference_codecs` to `offered_codecs` that don't |
| // already exist in `offered_codecs` and ensure the payload types don't |
| // collide. |
| void MergeCodecs(const CodecList& reference_codecs, |
| CodecList& offered_codecs, |
| UsedPayloadTypes* used_pltypes) { |
| // Add all new codecs that are not RTX/RED codecs. |
| // The two-pass splitting of the loops means preferring payload types |
| // of actual codecs with respect to collisions. |
| for (const Codec& reference_codec : reference_codecs) { |
| if (reference_codec.GetResiliencyType() != Codec::ResiliencyType::kRtx && |
| reference_codec.GetResiliencyType() != Codec::ResiliencyType::kRed && |
| !FindMatchingCodec(reference_codecs, offered_codecs, reference_codec)) { |
| Codec codec = reference_codec; |
| used_pltypes->FindAndSetIdUsed(&codec); |
| offered_codecs.push_back(codec); |
| } |
| } |
| |
| // Add all new RTX or RED codecs. |
| for (const Codec& reference_codec : reference_codecs) { |
| if (reference_codec.GetResiliencyType() == Codec::ResiliencyType::kRtx && |
| !FindMatchingCodec(reference_codecs, offered_codecs, reference_codec)) { |
| Codec rtx_codec = reference_codec; |
| const Codec* associated_codec = |
| GetAssociatedCodecForRtx(reference_codecs, rtx_codec); |
| if (!associated_codec) { |
| continue; |
| } |
| // Find a codec in the offered list that matches the reference codec. |
| // Its payload type may be different than the reference codec. |
| std::optional<Codec> matching_codec = FindMatchingCodec( |
| reference_codecs, offered_codecs, *associated_codec); |
| if (!matching_codec) { |
| RTC_LOG(LS_WARNING) |
| << "Couldn't find matching " << associated_codec->name << " codec."; |
| continue; |
| } |
| |
| rtx_codec.params[kCodecParamAssociatedPayloadType] = |
| rtc::ToString(matching_codec->id); |
| used_pltypes->FindAndSetIdUsed(&rtx_codec); |
| offered_codecs.push_back(rtx_codec); |
| } else if (reference_codec.GetResiliencyType() == |
| Codec::ResiliencyType::kRed && |
| !FindMatchingCodec(reference_codecs, offered_codecs, |
| reference_codec)) { |
| Codec red_codec = reference_codec; |
| const Codec* associated_codec = |
| GetAssociatedCodecForRed(reference_codecs, red_codec); |
| if (associated_codec) { |
| std::optional<Codec> matching_codec = FindMatchingCodec( |
| reference_codecs, offered_codecs, *associated_codec); |
| if (!matching_codec) { |
| RTC_LOG(LS_WARNING) << "Couldn't find matching " |
| << associated_codec->name << " codec."; |
| continue; |
| } |
| |
| red_codec.params[kCodecParamNotInNameValueFormat] = |
| rtc::ToString(matching_codec->id) + "/" + |
| rtc::ToString(matching_codec->id); |
| } |
| used_pltypes->FindAndSetIdUsed(&red_codec); |
| offered_codecs.push_back(red_codec); |
| } |
| } |
| offered_codecs.CheckConsistency(); |
| } |
| |
| // `codecs` is a full list of codecs with correct payload type mappings, which |
| // don't conflict with mappings of the other media type; `supported_codecs` is |
| // a list filtered for the media section`s direction but with default payload |
| // types. |
| // static |
| CodecList MatchCodecPreference( |
| const std::vector<webrtc::RtpCodecCapability>& codec_preferences, |
| const CodecList& codecs, |
| const CodecList& supported_codecs) { |
| CodecList filtered_codecs; |
| bool want_rtx = false; |
| bool want_red = false; |
| |
| for (const auto& codec_preference : codec_preferences) { |
| if (IsRtxCodec(codec_preference)) { |
| want_rtx = true; |
| } else if (IsRedCodec(codec_preference)) { |
| want_red = true; |
| } |
| } |
| bool red_was_added = false; |
| for (const auto& codec_preference : codec_preferences) { |
| auto found_codec = absl::c_find_if( |
| supported_codecs, [&codec_preference](const Codec& codec) { |
| // We should not filter out the codec in |codec_preferences| if it |
| // has a higher level than the codec in |supported_codecs|, as the |
| // codec in |supported_codecs| may be only with lower level in |
| // |send_codecs_| and |recv_codecs_| for the same codec. |
| return IsSameRtpCodecIgnoringLevel(codec, codec_preference); |
| }); |
| |
| if (found_codec != supported_codecs.end()) { |
| std::optional<Codec> found_codec_with_correct_pt = |
| FindMatchingCodec(supported_codecs, codecs, *found_codec); |
| if (found_codec_with_correct_pt) { |
| // RED may already have been added if its primary codec is before RED |
| // in the codec list. |
| bool is_red_codec = found_codec_with_correct_pt->GetResiliencyType() == |
| Codec::ResiliencyType::kRed; |
| if (!is_red_codec || !red_was_added) { |
| filtered_codecs.push_back(*found_codec_with_correct_pt); |
| red_was_added = is_red_codec ? true : red_was_added; |
| } |
| std::string id = rtc::ToString(found_codec_with_correct_pt->id); |
| // Search for the matching rtx or red codec. |
| if (want_red || want_rtx) { |
| for (const auto& codec : codecs) { |
| if (want_rtx && |
| codec.GetResiliencyType() == Codec::ResiliencyType::kRtx) { |
| const auto apt = |
| codec.params.find(cricket::kCodecParamAssociatedPayloadType); |
| if (apt != codec.params.end() && apt->second == id) { |
| filtered_codecs.push_back(codec); |
| break; |
| } |
| } else if (want_red && codec.GetResiliencyType() == |
| Codec::ResiliencyType::kRed) { |
| // For RED, do not insert the codec again if it was already |
| // inserted. audio/red for opus gets enabled by having RED before |
| // the primary codec. |
| const auto fmtp = |
| codec.params.find(cricket::kCodecParamNotInNameValueFormat); |
| if (fmtp != codec.params.end()) { |
| std::vector<absl::string_view> redundant_payloads = |
| rtc::split(fmtp->second, '/'); |
| if (!redundant_payloads.empty() && |
| redundant_payloads[0] == id) { |
| if (!red_was_added) { |
| filtered_codecs.push_back(codec); |
| red_was_added = true; |
| } |
| break; |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| return filtered_codecs; |
| } |
| |
| // Compute the union of `codecs1` and `codecs2`. |
| CodecList ComputeCodecsUnion(const CodecList codecs1, const CodecList codecs2) { |
| CodecList all_codecs; |
| UsedPayloadTypes used_payload_types; |
| for (const Codec& codec : codecs1) { |
| Codec codec_mutable = codec; |
| used_payload_types.FindAndSetIdUsed(&codec_mutable); |
| all_codecs.push_back(codec_mutable); |
| } |
| |
| // Use MergeCodecs to merge the second half of our list as it already checks |
| // and fixes problems with duplicate payload types. |
| MergeCodecs(codecs2, all_codecs, &used_payload_types); |
| |
| return all_codecs; |
| } |
| |
| RTCError MergeCodecsFromDescription( |
| const std::vector<const ContentInfo*>& current_active_contents, |
| CodecList& audio_codecs, |
| CodecList& video_codecs, |
| UsedPayloadTypes* used_pltypes) { |
| for (const ContentInfo* content : current_active_contents) { |
| RTCErrorOr<CodecList> checked_codec_list = |
| CodecList::Create(content->media_description()->codecs()); |
| if (!checked_codec_list.ok()) { |
| RTC_LOG(LS_ERROR) << checked_codec_list.error(); |
| } |
| if (IsMediaContentOfType(content, MEDIA_TYPE_AUDIO)) { |
| MergeCodecs(checked_codec_list.value(), audio_codecs, used_pltypes); |
| } else if (IsMediaContentOfType(content, MEDIA_TYPE_VIDEO)) { |
| MergeCodecs(checked_codec_list.value(), video_codecs, used_pltypes); |
| } |
| } |
| return RTCError::OK(); |
| } |
| |
| void NegotiatePacketization(const Codec& local_codec, |
| const Codec& remote_codec, |
| Codec* negotiated_codec) { |
| negotiated_codec->packetization = |
| (local_codec.packetization == remote_codec.packetization) |
| ? local_codec.packetization |
| : std::nullopt; |
| } |
| |
| #ifdef RTC_ENABLE_H265 |
| void NegotiateTxMode(const Codec& local_codec, |
| const Codec& remote_codec, |
| Codec* negotiated_codec) { |
| negotiated_codec->tx_mode = (local_codec.tx_mode == remote_codec.tx_mode) |
| ? local_codec.tx_mode |
| : std::nullopt; |
| } |
| #endif |
| |
| // For offer, negotiated codec must have the same level-id as that in |
| // |supported_codecs| with same profile. |
| void NegotiateVideoCodecLevelsForOffer( |
| const MediaDescriptionOptions& media_description_options, |
| const CodecList& supported_codecs, |
| CodecList& filtered_codecs) { |
| if (filtered_codecs.empty() || supported_codecs.empty()) { |
| return; |
| } |
| |
| // TODO(http://crbugs.com/376306259): We should handle level-idx for AV1. |
| // Ideally this should be done for all codecs, but RFCs of other codecs |
| // do not clear define the expected behavior for the level in the offer. |
| #ifdef RTC_ENABLE_H265 |
| if (media_description_options.type == MEDIA_TYPE_VIDEO) { |
| std::unordered_map<webrtc::H265Profile, webrtc::H265Level> |
| supported_h265_profiles; |
| // The assumption here is that H.265 codecs with the same profile and tier |
| // are already with highest level for that profile in both |
| // |supported_codecs| and |filtered_codecs|. |
| for (const Codec& supported_codec : supported_codecs) { |
| if (absl::EqualsIgnoreCase(supported_codec.name, kH265CodecName)) { |
| std::optional<webrtc::H265ProfileTierLevel> supported_ptl = |
| webrtc::ParseSdpForH265ProfileTierLevel(supported_codec.params); |
| if (supported_ptl.has_value()) { |
| supported_h265_profiles[supported_ptl->profile] = |
| supported_ptl->level; |
| } |
| } |
| } |
| |
| if (supported_h265_profiles.empty()) { |
| return; |
| } |
| |
| for (auto& filtered_codec : filtered_codecs) { |
| if (absl::EqualsIgnoreCase(filtered_codec.name, kH265CodecName)) { |
| std::optional<webrtc::H265ProfileTierLevel> filtered_ptl = |
| webrtc::ParseSdpForH265ProfileTierLevel(filtered_codec.params); |
| if (filtered_ptl.has_value()) { |
| auto it = supported_h265_profiles.find(filtered_ptl->profile); |
| |
| if (it != supported_h265_profiles.end() && |
| filtered_ptl->level != it->second) { |
| filtered_codec.params[kH265FmtpLevelId] = |
| webrtc::H265LevelToString(it->second); |
| } |
| } |
| } |
| } |
| } |
| #endif |
| } |
| |
| RTCError NegotiateCodecs(const CodecList& local_codecs, |
| const CodecList& offered_codecs, |
| CodecList& negotiated_codecs_out, |
| bool keep_offer_order) { |
| std::map<int, int> pt_mapping_table; |
| // Since we build the negotiated codec list one entry at a time, |
| // the list will have inconsistencies during building. |
| std::vector<Codec> negotiated_codecs; |
| for (const Codec& ours : local_codecs) { |
| std::optional<Codec> theirs = |
| FindMatchingCodec(local_codecs, offered_codecs, ours); |
| // Note that we intentionally only find one matching codec for each of our |
| // local codecs, in case the remote offer contains duplicate codecs. |
| if (theirs) { |
| Codec negotiated = ours; |
| NegotiatePacketization(ours, *theirs, &negotiated); |
| negotiated.IntersectFeedbackParams(*theirs); |
| if (negotiated.GetResiliencyType() == Codec::ResiliencyType::kRtx) { |
| // We support parsing the declarative rtx-time parameter. |
| const auto rtx_time_it = theirs->params.find(kCodecParamRtxTime); |
| if (rtx_time_it != theirs->params.end()) { |
| negotiated.SetParam(kCodecParamRtxTime, rtx_time_it->second); |
| } |
| } else if (negotiated.GetResiliencyType() == |
| Codec::ResiliencyType::kRed) { |
| const auto red_it = |
| theirs->params.find(kCodecParamNotInNameValueFormat); |
| if (red_it != theirs->params.end()) { |
| negotiated.SetParam(kCodecParamNotInNameValueFormat, red_it->second); |
| } |
| } |
| if (absl::EqualsIgnoreCase(ours.name, kH264CodecName)) { |
| webrtc::H264GenerateProfileLevelIdForAnswer(ours.params, theirs->params, |
| &negotiated.params); |
| } |
| #ifdef RTC_ENABLE_H265 |
| if (absl::EqualsIgnoreCase(ours.name, kH265CodecName)) { |
| webrtc::H265GenerateProfileTierLevelForAnswer( |
| ours.params, theirs->params, &negotiated.params); |
| NegotiateTxMode(ours, *theirs, &negotiated); |
| } |
| #endif |
| // Use their ID, if available. |
| pt_mapping_table.insert({negotiated.id, theirs->id}); |
| negotiated.id = theirs->id; |
| negotiated.name = theirs->name; |
| negotiated_codecs.push_back(std::move(negotiated)); |
| } |
| } |
| // Fix up apt parameters that point to other PTs. |
| for (Codec& negotiated : negotiated_codecs) { |
| if (negotiated.GetResiliencyType() == Codec::ResiliencyType::kRtx) { |
| // Change the apt value according to the pt mapping table. |
| // This avoids changing to apt values that don't exist any more. |
| std::string apt_str; |
| if (!negotiated.GetParam(kCodecParamAssociatedPayloadType, &apt_str)) { |
| RTC_LOG(LS_WARNING) << "No apt value"; |
| continue; |
| } |
| int apt_value; |
| if (!rtc::FromString(apt_str, &apt_value)) { |
| RTC_LOG(LS_WARNING) << "Unconvertable apt value"; |
| continue; |
| } |
| if (pt_mapping_table.count(apt_value) != 1) { |
| RTC_LOG(LS_WARNING) << "Unmapped apt value " << apt_value; |
| continue; |
| } |
| negotiated.SetParam(kCodecParamAssociatedPayloadType, |
| pt_mapping_table.at(apt_value)); |
| } |
| } |
| if (keep_offer_order) { |
| // RFC3264: Although the answerer MAY list the formats in their desired |
| // order of preference, it is RECOMMENDED that unless there is a |
| // specific reason, the answerer list formats in the same relative order |
| // they were present in the offer. |
| // This can be skipped when the transceiver has any codec preferences. |
| std::unordered_map<int, int> payload_type_preferences; |
| int preference = static_cast<int>(offered_codecs.size() + 1); |
| for (const Codec& codec : offered_codecs) { |
| payload_type_preferences[codec.id] = preference--; |
| } |
| absl::c_sort(negotiated_codecs, [&payload_type_preferences]( |
| const Codec& a, const Codec& b) { |
| return payload_type_preferences[a.id] > payload_type_preferences[b.id]; |
| }); |
| } |
| RTCErrorOr<CodecList> result = CodecList::Create(negotiated_codecs); |
| if (!result.ok()) { |
| return result.MoveError(); |
| } |
| negotiated_codecs_out = result.MoveValue(); |
| return RTCError::OK(); |
| } |
| |
| // Update the ID fields of the codec vector. |
| // If any codec has an ID with value "kIdNotSet", use the payload type suggester |
| // to assign and record a payload type for it. |
| // If there is a RED codec without its fmtp parameter, give it the ID of the |
| // first OPUS codec in the codec list. |
| webrtc::RTCError AssignCodecIdsAndLinkRed( |
| webrtc::PayloadTypeSuggester* pt_suggester, |
| const std::string& mid, |
| std::vector<Codec>& codecs) { |
| int codec_payload_type = Codec::kIdNotSet; |
| for (cricket::Codec& codec : codecs) { |
| if (codec.id == Codec::kIdNotSet) { |
| // Add payload types to codecs, if needed |
| // This should only happen if WebRTC-PayloadTypesInTransport field trial |
| // is enabled. |
| RTC_CHECK(pt_suggester); |
| auto result = pt_suggester->SuggestPayloadType(mid, codec); |
| if (!result.ok()) { |
| return result.error(); |
| } |
| codec.id = result.value(); |
| } |
| // record first Opus codec id |
| if (absl::EqualsIgnoreCase(codec.name, kOpusCodecName) && |
| codec_payload_type == Codec::kIdNotSet) { |
| codec_payload_type = codec.id; |
| } |
| } |
| if (codec_payload_type != Codec::kIdNotSet) { |
| for (cricket::Codec& codec : codecs) { |
| if (codec.type == Codec::Type::kAudio && |
| absl::EqualsIgnoreCase(codec.name, kRedCodecName)) { |
| if (codec.params.empty()) { |
| char buffer[100]; |
| rtc::SimpleStringBuilder param(buffer); |
| param << codec_payload_type << "/" << codec_payload_type; |
| codec.SetParam(kCodecParamNotInNameValueFormat, param.str()); |
| } |
| } |
| } |
| } |
| return webrtc::RTCError::OK(); |
| } |
| |
| } // namespace |
| |
| webrtc::RTCErrorOr<std::vector<Codec>> CodecVendor::GetNegotiatedCodecsForOffer( |
| const MediaDescriptionOptions& media_description_options, |
| const MediaSessionOptions& session_options, |
| const ContentInfo* current_content, |
| PayloadTypeSuggester& pt_suggester, |
| const CodecList& codecs) { |
| CodecList filtered_codecs; |
| CodecList supported_codecs = |
| media_description_options.type == MEDIA_TYPE_AUDIO |
| ? GetAudioCodecsForOffer(media_description_options.direction) |
| : GetVideoCodecsForOffer(media_description_options.direction); |
| |
| if (media_description_options.codecs_to_include.empty()) { |
| if (!media_description_options.codec_preferences.empty()) { |
| // Add the codecs from the current transceiver's codec preferences. |
| // They override any existing codecs from previous negotiations. |
| filtered_codecs = |
| MatchCodecPreference(media_description_options.codec_preferences, |
| codecs, supported_codecs); |
| } else { |
| // Add the codecs from current content if it exists and is not rejected |
| // nor recycled. |
| if (current_content && !current_content->rejected && |
| current_content->mid() == media_description_options.mid) { |
| if (!IsMediaContentOfType(current_content, |
| media_description_options.type)) { |
| // Can happen if the remote side re-uses a MID while recycling. |
| LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR, |
| "Media type for content with mid='" + |
| current_content->mid() + |
| "' does not match previous type."); |
| } |
| const MediaContentDescription* mcd = |
| current_content->media_description(); |
| for (const Codec& codec : mcd->codecs()) { |
| if (webrtc::FindMatchingCodec(mcd->codecs(), codecs.codecs(), |
| codec)) { |
| filtered_codecs.push_back(codec); |
| } |
| } |
| } |
| // Note what PTs are already in use. |
| UsedPayloadTypes |
| used_pltypes; // Used to avoid pt collisions in filtered_codecs |
| for (auto& codec : filtered_codecs) { |
| // Note: This may change PTs. Doing so woud indicate an error, but |
| // UsedPayloadTypes doesn't offer a means to make the distinction. |
| used_pltypes.FindAndSetIdUsed(&codec); |
| } |
| // Add other supported codecs. |
| for (const Codec& codec : supported_codecs) { |
| std::optional<Codec> found_codec = |
| FindMatchingCodec(supported_codecs, codecs, codec); |
| if (found_codec && |
| !FindMatchingCodec(supported_codecs, filtered_codecs, codec)) { |
| // Use the `found_codec` from `codecs` because it has the |
| // correctly mapped payload type (most of the time). |
| if (media_description_options.type == MEDIA_TYPE_VIDEO && |
| found_codec->GetResiliencyType() == Codec::ResiliencyType::kRtx) { |
| // For RTX we might need to adjust the apt parameter if we got a |
| // remote offer without RTX for a codec for which we support RTX. |
| // This is only done for video since we do not yet have rtx for |
| // audio. |
| auto referenced_codec = |
| GetAssociatedCodecForRtx(supported_codecs, codec); |
| RTC_DCHECK(referenced_codec); |
| |
| // Find the codec we should be referencing and point to it. |
| std::optional<Codec> changed_referenced_codec = FindMatchingCodec( |
| supported_codecs, filtered_codecs, *referenced_codec); |
| if (changed_referenced_codec) { |
| found_codec->SetParam(kCodecParamAssociatedPayloadType, |
| changed_referenced_codec->id); |
| } |
| } |
| // Quick fix for b/395077842: Remap the codec if it collides. |
| used_pltypes.FindAndSetIdUsed(&(*found_codec)); |
| filtered_codecs.push_back(*found_codec); |
| } |
| } |
| } |
| |
| if (media_description_options.type == MEDIA_TYPE_AUDIO && |
| !session_options.vad_enabled) { |
| // If application doesn't want CN codecs in offer. |
| StripCNCodecs(filtered_codecs); |
| } else if (media_description_options.type == MEDIA_TYPE_VIDEO && |
| session_options.raw_packetization_for_video) { |
| for (Codec& codec : filtered_codecs) { |
| if (codec.IsMediaCodec()) { |
| codec.packetization = kPacketizationParamRaw; |
| } |
| } |
| } |
| NegotiateVideoCodecLevelsForOffer(media_description_options, |
| supported_codecs, filtered_codecs); |
| } else { |
| // media_description_options.codecs_to_include contains codecs |
| // TODO: issues.webrtc.org/360058654 - figure out if this can be deleted. |
| RTCErrorOr<CodecList> codecs_from_arg = |
| CodecList::Create(media_description_options.codecs_to_include); |
| if (!codecs_from_arg.ok()) { |
| return codecs_from_arg.MoveError(); |
| } |
| filtered_codecs = codecs_from_arg.MoveValue(); |
| } |
| AssignCodecIdsAndLinkRed(&pt_suggester, media_description_options.mid, |
| filtered_codecs.writable_codecs()); |
| return filtered_codecs.codecs(); |
| } |
| |
| webrtc::RTCErrorOr<Codecs> CodecVendor::GetNegotiatedCodecsForAnswer( |
| const MediaDescriptionOptions& media_description_options, |
| const MediaSessionOptions& session_options, |
| webrtc::RtpTransceiverDirection offer_rtd, |
| webrtc::RtpTransceiverDirection answer_rtd, |
| const ContentInfo* current_content, |
| const std::vector<Codec> codecs_from_offer, |
| PayloadTypeSuggester& pt_suggester, |
| const CodecList& codecs) { |
| CodecList filtered_codecs; |
| CodecList negotiated_codecs; |
| if (media_description_options.codecs_to_include.empty()) { |
| const CodecList& supported_codecs = |
| media_description_options.type == MEDIA_TYPE_AUDIO |
| ? GetAudioCodecsForAnswer(offer_rtd, answer_rtd) |
| : GetVideoCodecsForAnswer(offer_rtd, answer_rtd); |
| if (!media_description_options.codec_preferences.empty()) { |
| filtered_codecs = |
| MatchCodecPreference(media_description_options.codec_preferences, |
| codecs, supported_codecs); |
| } else { |
| // Add the codecs from current content if it exists and is not rejected |
| // nor recycled. |
| if (current_content && !current_content->rejected && |
| current_content->mid() == media_description_options.mid) { |
| if (!IsMediaContentOfType(current_content, |
| media_description_options.type)) { |
| // Can happen if the remote side re-uses a MID while recycling. |
| LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR, |
| "Media type for content with mid='" + |
| current_content->mid() + |
| "' does not match previous type."); |
| } |
| const MediaContentDescription* mcd = |
| current_content->media_description(); |
| for (const Codec& codec : mcd->codecs()) { |
| if (webrtc::FindMatchingCodec(mcd->codecs(), codecs.codecs(), |
| codec)) { |
| filtered_codecs.push_back(codec); |
| } |
| } |
| } |
| // Add other supported codecs. |
| CodecList other_codecs; |
| for (const Codec& codec : supported_codecs) { |
| if (FindMatchingCodec(supported_codecs, codecs, codec) && |
| !FindMatchingCodec(supported_codecs, filtered_codecs, codec)) { |
| // We should use the local codec with local parameters and the codec |
| // id would be correctly mapped in `NegotiateCodecs`. |
| other_codecs.push_back(codec); |
| } |
| } |
| |
| // Use ComputeCodecsUnion to avoid having duplicate payload IDs. |
| // This is a no-op for audio until RTX is added. |
| filtered_codecs = ComputeCodecsUnion(filtered_codecs, other_codecs); |
| } |
| |
| if (media_description_options.type == MEDIA_TYPE_AUDIO && |
| !session_options.vad_enabled) { |
| // If application doesn't want CN codecs in offer. |
| StripCNCodecs(filtered_codecs); |
| } else if (media_description_options.type == MEDIA_TYPE_VIDEO && |
| session_options.raw_packetization_for_video) { |
| for (Codec& codec : filtered_codecs) { |
| if (codec.IsMediaCodec()) { |
| codec.packetization = kPacketizationParamRaw; |
| } |
| } |
| } |
| // An offer is external data, so needs to be checked before use. |
| auto checked_codecs_from_offer = CodecList::Create(codecs_from_offer); |
| if (!checked_codecs_from_offer.ok()) { |
| return checked_codecs_from_offer.MoveError(); |
| } |
| NegotiateCodecs(filtered_codecs, checked_codecs_from_offer.value(), |
| negotiated_codecs, |
| media_description_options.codec_preferences.empty()); |
| } else { |
| // media_description_options.codecs_to_include contains codecs |
| RTCErrorOr<CodecList> codecs_from_arg = |
| CodecList::Create(media_description_options.codecs_to_include); |
| if (!codecs_from_arg.ok()) { |
| return codecs_from_arg.MoveError(); |
| } |
| negotiated_codecs = codecs_from_arg.MoveValue(); |
| } |
| AssignCodecIdsAndLinkRed(&pt_suggester, media_description_options.mid, |
| negotiated_codecs.writable_codecs()); |
| return negotiated_codecs.codecs(); |
| } |
| |
| CodecVendor::CodecVendor(MediaEngineInterface* media_engine, |
| bool rtx_enabled, |
| const webrtc::FieldTrialsView& |
| trials) { // Null media_engine is permitted in |
| // order to allow unit testing where |
| // the codecs are explicitly set by the test. |
| if (media_engine) { |
| audio_send_codecs_ = |
| TypedCodecVendor(media_engine, MEDIA_TYPE_AUDIO, |
| /* is_sender= */ true, rtx_enabled, trials); |
| audio_recv_codecs_ = |
| TypedCodecVendor(media_engine, MEDIA_TYPE_AUDIO, |
| /* is_sender= */ false, rtx_enabled, trials); |
| video_send_codecs_ = |
| TypedCodecVendor(media_engine, MEDIA_TYPE_VIDEO, |
| /* is_sender= */ true, rtx_enabled, trials); |
| video_recv_codecs_ = |
| TypedCodecVendor(media_engine, MEDIA_TYPE_VIDEO, |
| /* is_sender= */ false, rtx_enabled, trials); |
| } |
| } |
| |
| const CodecList& CodecVendor::audio_send_codecs() const { |
| return audio_send_codecs_.codecs(); |
| } |
| |
| const CodecList& CodecVendor::audio_recv_codecs() const { |
| return audio_recv_codecs_.codecs(); |
| } |
| |
| void CodecVendor::set_audio_codecs(const CodecList& send_codecs, |
| const CodecList& recv_codecs) { |
| audio_send_codecs_.set_codecs(send_codecs); |
| audio_recv_codecs_.set_codecs(recv_codecs); |
| } |
| |
| const CodecList& CodecVendor::video_send_codecs() const { |
| return video_send_codecs_.codecs(); |
| } |
| |
| const CodecList& CodecVendor::video_recv_codecs() const { |
| return video_recv_codecs_.codecs(); |
| } |
| |
| void CodecVendor::set_video_codecs(const CodecList& send_codecs, |
| const CodecList& recv_codecs) { |
| video_send_codecs_.set_codecs(send_codecs); |
| video_recv_codecs_.set_codecs(recv_codecs); |
| } |
| // Getting codecs for an offer involves these steps: |
| // |
| // 1. Construct payload type -> codec mappings for current description. |
| // 2. Add any reference codecs that weren't already present |
| // 3. For each individual media description (m= section), filter codecs based |
| // on the directional attribute (happens in another method). |
| RTCError CodecVendor::GetCodecsForOffer( |
| const std::vector<const ContentInfo*>& current_active_contents, |
| CodecList& audio_codecs, |
| CodecList& video_codecs) const { |
| // First - get all codecs from the current description if the media type |
| // is used. Add them to `used_pltypes` so the payload type is not reused if a |
| // new media type is added. |
| UsedPayloadTypes used_pltypes; |
| auto error = MergeCodecsFromDescription(current_active_contents, audio_codecs, |
| video_codecs, &used_pltypes); |
| if (!error.ok()) { |
| return error; |
| } |
| // Add our codecs that are not in the current description. |
| MergeCodecs(all_audio_codecs(), audio_codecs, &used_pltypes); |
| MergeCodecs(all_video_codecs(), video_codecs, &used_pltypes); |
| return RTCError::OK(); |
| } |
| |
| // Getting codecs for an answer involves these steps: |
| // |
| // 1. Construct payload type -> codec mappings for current description. |
| // 2. Add any codecs from the offer that weren't already present. |
| // 3. Add any remaining codecs that weren't already present. |
| // 4. For each individual media description (m= section), filter codecs based |
| // on the directional attribute (happens in another method). |
| RTCError CodecVendor::GetCodecsForAnswer( |
| const std::vector<const ContentInfo*>& current_active_contents, |
| const SessionDescription& remote_offer, |
| CodecList& audio_codecs, |
| CodecList& video_codecs) const { |
| // First - get all codecs from the current description if the media type |
| // is used. Add them to `used_pltypes` so the payload type is not reused if a |
| // new media type is added. |
| UsedPayloadTypes used_pltypes; |
| RTCError error = MergeCodecsFromDescription( |
| current_active_contents, audio_codecs, video_codecs, &used_pltypes); |
| if (!error.ok()) { |
| return error; |
| } |
| // Second - filter out codecs that we don't support at all and should ignore. |
| CodecList filtered_offered_audio_codecs; |
| CodecList filtered_offered_video_codecs; |
| for (const ContentInfo& content : remote_offer.contents()) { |
| RTCErrorOr<CodecList> offered_codecs = |
| CodecList::Create(content.media_description()->codecs()); |
| if (!offered_codecs.ok()) { |
| return offered_codecs.MoveError(); |
| } |
| if (IsMediaContentOfType(&content, MEDIA_TYPE_AUDIO)) { |
| for (const Codec& offered_audio_codec : offered_codecs.value()) { |
| if (!FindMatchingCodec(offered_codecs.value(), |
| filtered_offered_audio_codecs, |
| offered_audio_codec) && |
| FindMatchingCodec(offered_codecs.value(), all_audio_codecs(), |
| offered_audio_codec)) { |
| filtered_offered_audio_codecs.push_back(offered_audio_codec); |
| } |
| } |
| } else if (IsMediaContentOfType(&content, MEDIA_TYPE_VIDEO)) { |
| std::vector<Codec> pending_rtx_codecs; |
| for (const Codec& offered_video_codec : offered_codecs.value()) { |
| if (!FindMatchingCodec(offered_codecs.value(), |
| filtered_offered_video_codecs, |
| offered_video_codec) && |
| FindMatchingCodec(offered_codecs.value(), all_video_codecs(), |
| offered_video_codec)) { |
| // Special case: If it's an RTX codec, and the APT points to |
| // a codec that is not yet in the codec list, put it aside. |
| if (offered_video_codec.GetResiliencyType() == |
| Codec::ResiliencyType::kRtx && |
| !GetAssociatedCodecForRtx(filtered_offered_video_codecs, |
| offered_video_codec)) { |
| pending_rtx_codecs.push_back(offered_video_codec); |
| continue; |
| } |
| filtered_offered_video_codecs.push_back(offered_video_codec); |
| } |
| } |
| // If the associated codec showed up later in the codec list, |
| // append the corresponding RTX codec. |
| for (const Codec& codec : pending_rtx_codecs) { |
| if (GetAssociatedCodecForRtx(filtered_offered_video_codecs, codec)) { |
| filtered_offered_video_codecs.push_back(codec); |
| } |
| } |
| } |
| } |
| |
| // Add codecs that are not in the current description but were in |
| // `remote_offer`. |
| MergeCodecs(filtered_offered_audio_codecs, audio_codecs, &used_pltypes); |
| MergeCodecs(filtered_offered_video_codecs, video_codecs, &used_pltypes); |
| return RTCError::OK(); |
| } |
| |
| CodecList CodecVendor::GetVideoCodecsForOffer( |
| const RtpTransceiverDirection& direction) const { |
| switch (direction) { |
| // If stream is inactive - generate list as if sendrecv. |
| case RtpTransceiverDirection::kSendRecv: |
| case RtpTransceiverDirection::kStopped: |
| case RtpTransceiverDirection::kInactive: |
| return video_sendrecv_codecs(); |
| case RtpTransceiverDirection::kSendOnly: |
| return video_send_codecs_.codecs(); |
| case RtpTransceiverDirection::kRecvOnly: |
| return video_recv_codecs_.codecs(); |
| } |
| RTC_CHECK_NOTREACHED(); |
| } |
| |
| CodecList CodecVendor::GetVideoCodecsForAnswer( |
| const RtpTransceiverDirection& offer, |
| const RtpTransceiverDirection& answer) const { |
| switch (answer) { |
| // For inactive and sendrecv answers, generate lists as if we were to accept |
| // the offer's direction. See RFC 3264 Section 6.1. |
| case RtpTransceiverDirection::kSendRecv: |
| case RtpTransceiverDirection::kStopped: |
| case RtpTransceiverDirection::kInactive: |
| return GetVideoCodecsForOffer( |
| webrtc::RtpTransceiverDirectionReversed(offer)); |
| case RtpTransceiverDirection::kSendOnly: |
| return video_send_codecs_.codecs(); |
| case RtpTransceiverDirection::kRecvOnly: |
| return video_recv_codecs_.codecs(); |
| } |
| RTC_CHECK_NOTREACHED(); |
| } |
| |
| CodecList CodecVendor::GetAudioCodecsForOffer( |
| const RtpTransceiverDirection& direction) const { |
| switch (direction) { |
| // If stream is inactive - generate list as if sendrecv. |
| case RtpTransceiverDirection::kSendRecv: |
| case RtpTransceiverDirection::kStopped: |
| case RtpTransceiverDirection::kInactive: |
| return audio_sendrecv_codecs(); |
| case RtpTransceiverDirection::kSendOnly: |
| return audio_send_codecs_.codecs(); |
| case RtpTransceiverDirection::kRecvOnly: |
| return audio_recv_codecs_.codecs(); |
| } |
| RTC_CHECK_NOTREACHED(); |
| } |
| |
| CodecList CodecVendor::GetAudioCodecsForAnswer( |
| const RtpTransceiverDirection& offer, |
| const RtpTransceiverDirection& answer) const { |
| switch (answer) { |
| // For inactive and sendrecv answers, generate lists as if we were to accept |
| // the offer's direction. See RFC 3264 Section 6.1. |
| case RtpTransceiverDirection::kSendRecv: |
| case RtpTransceiverDirection::kStopped: |
| case RtpTransceiverDirection::kInactive: |
| return GetAudioCodecsForOffer( |
| webrtc::RtpTransceiverDirectionReversed(offer)); |
| case RtpTransceiverDirection::kSendOnly: |
| return audio_send_codecs_.codecs(); |
| case RtpTransceiverDirection::kRecvOnly: |
| return audio_recv_codecs_.codecs(); |
| } |
| RTC_CHECK_NOTREACHED(); |
| } |
| |
| CodecList CodecVendor::all_video_codecs() const { |
| // Use ComputeCodecsUnion to avoid having duplicate payload IDs |
| return ComputeCodecsUnion(video_recv_codecs_.codecs(), |
| video_send_codecs_.codecs()); |
| } |
| |
| CodecList CodecVendor::all_audio_codecs() const { |
| // Compute the audio codecs union. |
| CodecList codecs; |
| for (const Codec& send : audio_send_codecs_.codecs()) { |
| codecs.push_back(send); |
| if (!FindMatchingCodec(audio_send_codecs_.codecs(), |
| audio_recv_codecs_.codecs(), send)) { |
| // It doesn't make sense to have an RTX codec we support sending but not |
| // receiving. |
| RTC_DCHECK(send.GetResiliencyType() != Codec::ResiliencyType::kRtx); |
| } |
| } |
| for (const Codec& recv : audio_recv_codecs_.codecs()) { |
| if (!FindMatchingCodec(audio_recv_codecs_.codecs(), |
| audio_send_codecs_.codecs(), recv)) { |
| codecs.push_back(recv); |
| } |
| } |
| return codecs; |
| } |
| |
| CodecList CodecVendor::audio_sendrecv_codecs() const { |
| // Use NegotiateCodecs to merge our codec lists, since the operation is |
| // essentially the same. Put send_codecs as the offered_codecs, which is the |
| // order we'd like to follow. The reasoning is that encoding is usually more |
| // expensive than decoding, and prioritizing a codec in the send list probably |
| // means it's a codec we can handle efficiently. |
| CodecList audio_sendrecv_codecs; |
| auto error = |
| NegotiateCodecs(audio_recv_codecs_.codecs(), audio_send_codecs_.codecs(), |
| audio_sendrecv_codecs, true); |
| RTC_DCHECK(error.ok()); |
| return audio_sendrecv_codecs; |
| } |
| |
| CodecList CodecVendor::video_sendrecv_codecs() const { |
| // Use NegotiateCodecs to merge our codec lists, since the operation is |
| // essentially the same. Put send_codecs as the offered_codecs, which is the |
| // order we'd like to follow. The reasoning is that encoding is usually more |
| // expensive than decoding, and prioritizing a codec in the send list probably |
| // means it's a codec we can handle efficiently. |
| // Also for the same profile of a codec, if there are different levels in the |
| // send and receive codecs, |video_sendrecv_codecs| will contain the lower |
| // level of the two for that profile. |
| CodecList video_sendrecv_codecs; |
| auto error = |
| NegotiateCodecs(video_recv_codecs_.codecs(), video_send_codecs_.codecs(), |
| video_sendrecv_codecs, true); |
| RTC_DCHECK(error.ok()); |
| return video_sendrecv_codecs; |
| } |
| |
| } // namespace cricket |
