1 files changed, 670 insertions, 0 deletions
diff --git a/dom/media/webrtc/jsep/JsepTrack.cpp b/dom/media/webrtc/jsep/JsepTrack.cpp
new file mode 100644
index 0000000000..f60e4ce0d7
--- /dev/null
+++ b/dom/media/webrtc/jsep/JsepTrack.cpp
@@ -0,0 +1,670 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "jsep/JsepTrack.h"
+#include "jsep/JsepCodecDescription.h"
+#include "jsep/JsepTrackEncoding.h"
+
+#include <algorithm>
+
+namespace mozilla {
+void JsepTrack::GetNegotiatedPayloadTypes(
+    std::vector<uint16_t>* payloadTypes) const {
+  if (!mNegotiatedDetails) {
+    return;
+  }
+
+  for (const auto& encoding : mNegotiatedDetails->mEncodings) {
+    GetPayloadTypes(encoding->GetCodecs(), payloadTypes);
+  }
+
+  // Prune out dupes
+  std::sort(payloadTypes->begin(), payloadTypes->end());
+  auto newEnd = std::unique(payloadTypes->begin(), payloadTypes->end());
+  payloadTypes->erase(newEnd, payloadTypes->end());
+}
+
+/* static */
+void JsepTrack::GetPayloadTypes(
+    const std::vector<UniquePtr<JsepCodecDescription>>& codecs,
+    std::vector<uint16_t>* payloadTypes) {
+  for (const auto& codec : codecs) {
+    uint16_t pt;
+    if (!codec->GetPtAsInt(&pt)) {
+      MOZ_ASSERT(false);
+      continue;
+    }
+    payloadTypes->push_back(pt);
+  }
+}
+
+void JsepTrack::EnsureNoDuplicatePayloadTypes(
+    std::vector<UniquePtr<JsepCodecDescription>>* codecs) {
+  std::set<std::string> uniquePayloadTypes;
+  for (auto& codec : *codecs) {
+    codec->EnsureNoDuplicatePayloadTypes(uniquePayloadTypes);
+  }
+}
+
+void JsepTrack::EnsureSsrcs(SsrcGenerator& ssrcGenerator, size_t aNumber) {
+  while (mSsrcs.size() < aNumber) {
+    uint32_t ssrc, rtxSsrc;
+    if (!ssrcGenerator.GenerateSsrc(&ssrc) ||
+        !ssrcGenerator.GenerateSsrc(&rtxSsrc)) {
+      return;
+    }
+    mSsrcs.push_back(ssrc);
+    mSsrcToRtxSsrc[ssrc] = rtxSsrc;
+    MOZ_ASSERT(mSsrcs.size() == mSsrcToRtxSsrc.size());
+  }
+}
+
+void JsepTrack::PopulateCodecs(
+    const std::vector<UniquePtr<JsepCodecDescription>>& prototype) {
+  mPrototypeCodecs.clear();
+  for (const auto& prototypeCodec : prototype) {
+    if (prototypeCodec->Type() == mType) {
+      mPrototypeCodecs.emplace_back(prototypeCodec->Clone());
+      mPrototypeCodecs.back()->mDirection = mDirection;
+    }
+  }
+
+  EnsureNoDuplicatePayloadTypes(&mPrototypeCodecs);
+}
+
+void JsepTrack::AddToOffer(SsrcGenerator& ssrcGenerator,
+                           SdpMediaSection* offer) {
+  AddToMsection(mPrototypeCodecs, offer);
+
+  if (mDirection == sdp::kSend) {
+    std::vector<std::string> rids;
+    if (offer->IsSending()) {
+      rids = mRids;
+    }
+
+    AddToMsection(rids, sdp::kSend, ssrcGenerator,
+                  IsRtxEnabled(mPrototypeCodecs), offer);
+  }
+}
+
+void JsepTrack::AddToAnswer(const SdpMediaSection& offer,
+                            SsrcGenerator& ssrcGenerator,
+                            SdpMediaSection* answer) {
+  // We do not modify mPrototypeCodecs here, since we're only creating an
+  // answer. Once offer/answer concludes, we will update mPrototypeCodecs.
+  std::vector<UniquePtr<JsepCodecDescription>> codecs =
+      NegotiateCodecs(offer, true, Nothing());
+  if (codecs.empty()) {
+    return;
+  }
+
+  AddToMsection(codecs, answer);
+
+  if (mDirection == sdp::kSend) {
+    AddToMsection(mRids, sdp::kSend, ssrcGenerator, IsRtxEnabled(codecs),
+                  answer);
+  }
+}
+
+void JsepTrack::SetRids(const std::vector<std::string>& aRids) {
+  MOZ_ASSERT(!aRids.empty());
+  if (!mRids.empty()) {
+    return;
+  }
+  mRids = aRids;
+}
+
+void JsepTrack::SetMaxEncodings(size_t aMax) {
+  mMaxEncodings = aMax;
+  if (mRids.size() > mMaxEncodings) {
+    mRids.resize(mMaxEncodings);
+  }
+}
+
+void JsepTrack::RecvTrackSetRemote(const Sdp& aSdp,
+                                   const SdpMediaSection& aMsection) {
+  mInHaveRemote = true;
+  MOZ_ASSERT(mDirection == sdp::kRecv);
+  MOZ_ASSERT(aMsection.GetMediaType() !=
+             SdpMediaSection::MediaType::kApplication);
+  std::string error;
+  SdpHelper helper(&error);
+
+  mRemoteSetSendBit = aMsection.IsSending();
+  if (!mRemoteSetSendBit) {
+    mReceptive = false;
+  }
+
+  if (aMsection.IsSending()) {
+    (void)helper.GetIdsFromMsid(aSdp, aMsection, &mStreamIds);
+  } else {
+    mStreamIds.clear();
+  }
+
+  // We do this whether or not the track is active
+  SetCNAME(helper.GetCNAME(aMsection));
+  mSsrcs.clear();
+  if (aMsection.GetAttributeList().HasAttribute(SdpAttribute::kSsrcAttribute)) {
+    for (const auto& ssrcAttr : aMsection.GetAttributeList().GetSsrc().mSsrcs) {
+      mSsrcs.push_back(ssrcAttr.ssrc);
+    }
+  }
+
+  // Use FID ssrc-group to associate rtx ssrcs with "regular" ssrcs. Despite
+  // not being part of RFC 4588, this is how rtx is negotiated by libwebrtc
+  // and jitsi.
+  mSsrcToRtxSsrc.clear();
+  if (aMsection.GetAttributeList().HasAttribute(
+          SdpAttribute::kSsrcGroupAttribute)) {
+    for (const auto& group :
+         aMsection.GetAttributeList().GetSsrcGroup().mSsrcGroups) {
+      if (group.semantics == SdpSsrcGroupAttributeList::kFid &&
+          group.ssrcs.size() == 2) {
+        // Ensure we have a "regular" ssrc for each rtx ssrc.
+        if (std::find(mSsrcs.begin(), mSsrcs.end(), group.ssrcs[0]) !=
+            mSsrcs.end()) {
+          mSsrcToRtxSsrc[group.ssrcs[0]] = group.ssrcs[1];
+
+          // Remove rtx ssrcs from mSsrcs
+          auto res = std::remove_if(
+              mSsrcs.begin(), mSsrcs.end(),
+              [group](uint32_t ssrc) { return ssrc == group.ssrcs[1]; });
+          mSsrcs.erase(res, mSsrcs.end());
+        }
+      }
+    }
+  }
+}
+
+void JsepTrack::RecvTrackSetLocal(const SdpMediaSection& aMsection) {
+  MOZ_ASSERT(mDirection == sdp::kRecv);
+
+  // TODO: Should more stuff live in here? Anything that needs to happen when we
+  // decide we're ready to receive packets should probably go in here.
+  mReceptive = aMsection.IsReceiving();
+}
+
+void JsepTrack::SendTrackSetRemote(SsrcGenerator& aSsrcGenerator,
+                                   const SdpMediaSection& aRemoteMsection) {
+  mInHaveRemote = true;
+  if (mType == SdpMediaSection::kApplication) {
+    return;
+  }
+
+  std::vector<SdpRidAttributeList::Rid> rids;
+
+  // TODO: Current language in webrtc-pc is completely broken, and so I will
+  // not be quoting it here.
+  if ((mType == SdpMediaSection::kVideo) &&
+      aRemoteMsection.GetAttributeList().HasAttribute(
+          SdpAttribute::kSimulcastAttribute)) {
+    // Note: webrtc-pc does not appear to support the full IETF simulcast
+    // spec. In particular, the IETF simulcast spec supports requesting
+    // multiple different sets of encodings. For example, "a=simulcast:send
+    // 1,2;3,4;5,6" means that there are three simulcast streams, the first of
+    // which can use either rid 1 or 2 (but not both), the second of which can
+    // use rid 3 or 4 (but not both), and the third of which can use rid 5 or
+    // 6 (but not both). webrtc-pc does not support this either/or stuff for
+    // rid; each simulcast stream gets exactly one rid.
+    // Also, webrtc-pc does not support the '~' pause syntax at all
+    // See https://github.com/w3c/webrtc-pc/issues/2769
+    GetRids(aRemoteMsection, sdp::kRecv, &rids);
+  }
+
+  if (mRids.empty()) {
+    // Initial configuration
+    for (const auto& ridAttr : rids) {
+      // TODO: Spec might change, making a length > 16 invalid SDP.
+      std::string dummy;
+      if (SdpRidAttributeList::CheckRidValidity(ridAttr.id, &dummy) &&
+          ridAttr.id.size() <= SdpRidAttributeList::kMaxRidLength) {
+        mRids.push_back(ridAttr.id);
+      }
+    }
+    if (mRids.size() > mMaxEncodings) {
+      mRids.resize(mMaxEncodings);
+    }
+  } else {
+    // JSEP is allowed to remove or reorder rids. RTCRtpSender won't pay
+    // attention to reordering.
+    std::vector<std::string> newRids;
+    for (const auto& ridAttr : rids) {
+      for (const auto& oldRid : mRids) {
+        if (oldRid == ridAttr.id) {
+          newRids.push_back(oldRid);
+          break;
+        }
+      }
+    }
+    mRids = std::move(newRids);
+  }
+
+  if (mRids.empty()) {
+    mRids.push_back("");
+  }
+
+  UpdateSsrcs(aSsrcGenerator, mRids.size());
+}
+
+void JsepTrack::AddToMsection(
+    const std::vector<UniquePtr<JsepCodecDescription>>& codecs,
+    SdpMediaSection* msection) const {
+  MOZ_ASSERT(msection->GetMediaType() == mType);
+  MOZ_ASSERT(!codecs.empty());
+
+  for (const auto& codec : codecs) {
+    codec->AddToMediaSection(*msection);
+  }
+
+  if ((mDirection == sdp::kSend) && (mType != SdpMediaSection::kApplication) &&
+      msection->IsSending()) {
+    if (mStreamIds.empty()) {
+      msection->AddMsid("-", mTrackId);
+    } else {
+      for (const std::string& streamId : mStreamIds) {
+        msection->AddMsid(streamId, mTrackId);
+      }
+    }
+  }
+}
+
+void JsepTrack::UpdateSsrcs(SsrcGenerator& ssrcGenerator, size_t encodings) {
+  MOZ_ASSERT(mDirection == sdp::kSend);
+  MOZ_ASSERT(mType != SdpMediaSection::kApplication);
+  size_t numSsrcs = std::max<size_t>(encodings, 1U);
+
+  EnsureSsrcs(ssrcGenerator, numSsrcs);
+  PruneSsrcs(numSsrcs);
+  if (mNegotiatedDetails && mNegotiatedDetails->GetEncodingCount() > numSsrcs) {
+    mNegotiatedDetails->TruncateEncodings(numSsrcs);
+  }
+
+  MOZ_ASSERT(!mSsrcs.empty());
+}
+
+void JsepTrack::PruneSsrcs(size_t aNumSsrcs) {
+  mSsrcs.resize(aNumSsrcs);
+
+  // We might have duplicate entries in mSsrcs, so we need to resize first and
+  // then remove ummatched rtx ssrcs.
+  auto itor = mSsrcToRtxSsrc.begin();
+  while (itor != mSsrcToRtxSsrc.end()) {
+    if (std::find(mSsrcs.begin(), mSsrcs.end(), itor->first) == mSsrcs.end()) {
+      itor = mSsrcToRtxSsrc.erase(itor);
+    } else {
+      ++itor;
+    }
+  }
+}
+
+bool JsepTrack::IsRtxEnabled(
+    const std::vector<UniquePtr<JsepCodecDescription>>& codecs) const {
+  for (const auto& codec : codecs) {
+    if (codec->Type() == SdpMediaSection::kVideo &&
+        static_cast<const JsepVideoCodecDescription*>(codec.get())
+            ->mRtxEnabled) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+void JsepTrack::AddToMsection(const std::vector<std::string>& aRids,
+                              sdp::Direction direction,
+                              SsrcGenerator& ssrcGenerator, bool rtxEnabled,
+                              SdpMediaSection* msection) {
+  if (aRids.size() > 1) {
+    UniquePtr<SdpSimulcastAttribute> simulcast(new SdpSimulcastAttribute);
+    UniquePtr<SdpRidAttributeList> ridAttrs(new SdpRidAttributeList);
+    for (const std::string& rid : aRids) {
+      SdpRidAttributeList::Rid ridAttr;
+      ridAttr.id = rid;
+      ridAttr.direction = direction;
+      ridAttrs->mRids.push_back(ridAttr);
+
+      SdpSimulcastAttribute::Version version;
+      version.choices.push_back(SdpSimulcastAttribute::Encoding(rid, false));
+      if (direction == sdp::kSend) {
+        simulcast->sendVersions.push_back(version);
+      } else {
+        simulcast->recvVersions.push_back(version);
+      }
+    }
+
+    msection->GetAttributeList().SetAttribute(simulcast.release());
+    msection->GetAttributeList().SetAttribute(ridAttrs.release());
+  }
+
+  bool requireRtxSsrcs = rtxEnabled && msection->IsSending();
+
+  if (mType != SdpMediaSection::kApplication && mDirection == sdp::kSend) {
+    UpdateSsrcs(ssrcGenerator, aRids.size());
+
+    if (requireRtxSsrcs) {
+      MOZ_ASSERT(mSsrcs.size() == mSsrcToRtxSsrc.size());
+      std::vector<uint32_t> allSsrcs;
+      UniquePtr<SdpSsrcGroupAttributeList> group(new SdpSsrcGroupAttributeList);
+      for (const auto& ssrc : mSsrcs) {
+        const auto rtxSsrc = mSsrcToRtxSsrc[ssrc];
+        allSsrcs.push_back(ssrc);
+        allSsrcs.push_back(rtxSsrc);
+        group->PushEntry(SdpSsrcGroupAttributeList::kFid, {ssrc, rtxSsrc});
+      }
+      msection->SetSsrcs(allSsrcs, mCNAME);
+      msection->GetAttributeList().SetAttribute(group.release());
+    } else {
+      msection->SetSsrcs(mSsrcs, mCNAME);
+    }
+  }
+}
+
+void JsepTrack::GetRids(const SdpMediaSection& msection,
+                        sdp::Direction direction,
+                        std::vector<SdpRidAttributeList::Rid>* rids) const {
+  rids->clear();
+  if (!msection.GetAttributeList().HasAttribute(
+          SdpAttribute::kSimulcastAttribute)) {
+    return;
+  }
+
+  const SdpSimulcastAttribute& simulcast(
+      msection.GetAttributeList().GetSimulcast());
+
+  const SdpSimulcastAttribute::Versions* versions = nullptr;
+  switch (direction) {
+    case sdp::kSend:
+      versions = &simulcast.sendVersions;
+      break;
+    case sdp::kRecv:
+      versions = &simulcast.recvVersions;
+      break;
+  }
+
+  if (!versions->IsSet()) {
+    return;
+  }
+
+  // RFC 8853 does not seem to forbid duplicate rids in a simulcast attribute.
+  // So, while this is obviously silly, we should be prepared for it and
+  // ignore those duplicate rids.
+  std::set<std::string> uniqueRids;
+  for (const SdpSimulcastAttribute::Version& version : *versions) {
+    if (!version.choices.empty() && !uniqueRids.count(version.choices[0].rid)) {
+      // We validate that rids are present (and sane) elsewhere.
+      rids->push_back(*msection.FindRid(version.choices[0].rid));
+      uniqueRids.insert(version.choices[0].rid);
+    }
+  }
+}
+
+void JsepTrack::CreateEncodings(
+    const SdpMediaSection& remote,
+    const std::vector<UniquePtr<JsepCodecDescription>>& negotiatedCodecs,
+    JsepTrackNegotiatedDetails* negotiatedDetails) {
+  negotiatedDetails->mTias = remote.GetBandwidth("TIAS");
+
+  webrtc::RtcpMode rtcpMode = webrtc::RtcpMode::kCompound;
+  // rtcp-rsize (video only)
+  if (remote.GetMediaType() == SdpMediaSection::kVideo &&
+      remote.GetAttributeList().HasAttribute(
+          SdpAttribute::kRtcpRsizeAttribute)) {
+    rtcpMode = webrtc::RtcpMode::kReducedSize;
+  }
+  negotiatedDetails->mRtpRtcpConf = RtpRtcpConfig(rtcpMode);
+
+  // TODO add support for b=AS if TIAS is not set (bug 976521)
+
+  if (mRids.empty()) {
+    mRids.push_back("");
+  }
+
+  size_t numEncodings = mRids.size();
+
+  // Drop SSRCs if fewer RIDs were offered than we have encodings
+  if (mSsrcs.size() > numEncodings) {
+    PruneSsrcs(numEncodings);
+  }
+
+  // For each stream make sure we have an encoding, and configure
+  // that encoding appropriately.
+  for (size_t i = 0; i < numEncodings; ++i) {
+    UniquePtr<JsepTrackEncoding> encoding(new JsepTrackEncoding);
+    if (mRids.size() > i) {
+      encoding->mRid = mRids[i];
+    }
+    for (const auto& codec : negotiatedCodecs) {
+      encoding->AddCodec(*codec);
+    }
+    negotiatedDetails->mEncodings.push_back(std::move(encoding));
+  }
+}
+
+std::vector<UniquePtr<JsepCodecDescription>> JsepTrack::GetCodecClones() const {
+  std::vector<UniquePtr<JsepCodecDescription>> clones;
+  for (const auto& codec : mPrototypeCodecs) {
+    clones.emplace_back(codec->Clone());
+  }
+  return clones;
+}
+
+static bool CompareCodec(const UniquePtr<JsepCodecDescription>& lhs,
+                         const UniquePtr<JsepCodecDescription>& rhs) {
+  return lhs->mStronglyPreferred && !rhs->mStronglyPreferred;
+}
+
+std::vector<UniquePtr<JsepCodecDescription>> JsepTrack::NegotiateCodecs(
+    const SdpMediaSection& remote, bool remoteIsOffer,
+    Maybe<const SdpMediaSection&> local) {
+  std::vector<UniquePtr<JsepCodecDescription>> negotiatedCodecs;
+  std::vector<UniquePtr<JsepCodecDescription>> newPrototypeCodecs;
+
+  // Outer loop establishes the remote side's preference
+  for (const std::string& fmt : remote.GetFormats()) {
+    for (auto& codec : mPrototypeCodecs) {
+      if (!codec || !codec->mEnabled || !codec->Matches(fmt, remote)) {
+        continue;
+      }
+
+      // First codec of ours that matches. See if we can negotiate it.
+      UniquePtr<JsepCodecDescription> clone(codec->Clone());
+      if (clone->Negotiate(fmt, remote, remoteIsOffer, local)) {
+        // If negotiation succeeded, remember the payload type the other side
+        // used for reoffers.
+        codec->mDefaultPt = fmt;
+
+        // Remember whether we negotiated rtx and the associated pt for later.
+        if (codec->Type() == SdpMediaSection::kVideo) {
+          JsepVideoCodecDescription* videoCodec =
+              static_cast<JsepVideoCodecDescription*>(codec.get());
+          JsepVideoCodecDescription* cloneVideoCodec =
+              static_cast<JsepVideoCodecDescription*>(clone.get());
+          bool useRtx =
+              mRtxIsAllowed &&
+              Preferences::GetBool("media.peerconnection.video.use_rtx", false);
+          videoCodec->mRtxEnabled = useRtx && cloneVideoCodec->mRtxEnabled;
+          videoCodec->mRtxPayloadType = cloneVideoCodec->mRtxPayloadType;
+        }
+
+        // Moves the codec out of mPrototypeCodecs, leaving an empty
+        // UniquePtr, so we don't use it again. Also causes successfully
+        // negotiated codecs to be placed up front in the future.
+        newPrototypeCodecs.emplace_back(std::move(codec));
+        negotiatedCodecs.emplace_back(std::move(clone));
+        break;
+      }
+    }
+  }
+
+  // newPrototypeCodecs contains just the negotiated stuff so far. Add the rest.
+  for (auto& codec : mPrototypeCodecs) {
+    if (codec) {
+      newPrototypeCodecs.emplace_back(std::move(codec));
+    }
+  }
+
+  // Negotiated stuff is up front, so it will take precedence when ensuring
+  // there are no duplicate payload types.
+  EnsureNoDuplicatePayloadTypes(&newPrototypeCodecs);
+  std::swap(newPrototypeCodecs, mPrototypeCodecs);
+
+  // Find the (potential) red codec and ulpfec codec or telephone-event
+  JsepVideoCodecDescription* red = nullptr;
+  JsepVideoCodecDescription* ulpfec = nullptr;
+  JsepAudioCodecDescription* dtmf = nullptr;
+  // We can safely cast here since JsepTrack has a MediaType and only codecs
+  // that match that MediaType (kAudio or kVideo) are added.
+  for (auto& codec : negotiatedCodecs) {
+    if (codec->mName == "red") {
+      red = static_cast<JsepVideoCodecDescription*>(codec.get());
+    } else if (codec->mName == "ulpfec") {
+      ulpfec = static_cast<JsepVideoCodecDescription*>(codec.get());
+    } else if (codec->mName == "telephone-event") {
+      dtmf = static_cast<JsepAudioCodecDescription*>(codec.get());
+    }
+  }
+  // if we have a red codec remove redundant encodings that don't exist
+  if (red) {
+    // Since we could have an externally specified redundant endcodings
+    // list, we shouldn't simply rebuild the redundant encodings list
+    // based on the current list of codecs.
+    std::vector<uint8_t> unnegotiatedEncodings;
+    std::swap(unnegotiatedEncodings, red->mRedundantEncodings);
+    for (auto redundantPt : unnegotiatedEncodings) {
+      std::string pt = std::to_string(redundantPt);
+      for (const auto& codec : negotiatedCodecs) {
+        if (pt == codec->mDefaultPt) {
+          red->mRedundantEncodings.push_back(redundantPt);
+          break;
+        }
+      }
+    }
+  }
+  // Video FEC is indicated by the existence of the red and ulpfec
+  // codecs and not an attribute on the particular video codec (like in
+  // a rtcpfb attr). If we see both red and ulpfec codecs, we enable FEC
+  // on all the other codecs.
+  if (red && ulpfec) {
+    for (auto& codec : negotiatedCodecs) {
+      if (codec->mName != "red" && codec->mName != "ulpfec") {
+        JsepVideoCodecDescription* videoCodec =
+            static_cast<JsepVideoCodecDescription*>(codec.get());
+        videoCodec->EnableFec(red->mDefaultPt, ulpfec->mDefaultPt);
+      }
+    }
+  }
+
+  // Dtmf support is indicated by the existence of the telephone-event
+  // codec, and not an attribute on the particular audio codec (like in a
+  // rtcpfb attr). If we see the telephone-event codec, we enabled dtmf
+  // support on all the other audio codecs.
+  if (dtmf) {
+    for (auto& codec : negotiatedCodecs) {
+      JsepAudioCodecDescription* audioCodec =
+          static_cast<JsepAudioCodecDescription*>(codec.get());
+      audioCodec->mDtmfEnabled = true;
+    }
+  }
+
+  // Make sure strongly preferred codecs are up front, overriding the remote
+  // side's preference.
+  std::stable_sort(negotiatedCodecs.begin(), negotiatedCodecs.end(),
+                   CompareCodec);
+
+  if (!red) {
+    // No red, remove ulpfec
+    negotiatedCodecs.erase(
+        std::remove_if(negotiatedCodecs.begin(), negotiatedCodecs.end(),
+                       [ulpfec](const UniquePtr<JsepCodecDescription>& codec) {
+                         return codec.get() == ulpfec;
+                       }),
+        negotiatedCodecs.end());
+    // Make sure there's no dangling ptr here
+    ulpfec = nullptr;
+  }
+
+  return negotiatedCodecs;
+}
+
+nsresult JsepTrack::Negotiate(const SdpMediaSection& answer,
+                              const SdpMediaSection& remote,
+                              const SdpMediaSection& local) {
+  std::vector<UniquePtr<JsepCodecDescription>> negotiatedCodecs =
+      NegotiateCodecs(remote, &answer != &remote, SomeRef(local));
+
+  if (negotiatedCodecs.empty()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  UniquePtr<JsepTrackNegotiatedDetails> negotiatedDetails =
+      MakeUnique<JsepTrackNegotiatedDetails>();
+
+  CreateEncodings(remote, negotiatedCodecs, negotiatedDetails.get());
+
+  if (answer.GetAttributeList().HasAttribute(SdpAttribute::kExtmapAttribute)) {
+    for (auto& extmapAttr : answer.GetAttributeList().GetExtmap().mExtmaps) {
+      SdpDirectionAttribute::Direction direction = extmapAttr.direction;
+      if (&remote == &answer) {
+        // Answer is remote, we need to flip this.
+        direction = reverse(direction);
+      }
+
+      if (direction & mDirection) {
+        negotiatedDetails->mExtmap[extmapAttr.extensionname] = extmapAttr;
+      }
+    }
+  }
+
+  mInHaveRemote = false;
+  mNegotiatedDetails = std::move(negotiatedDetails);
+  return NS_OK;
+}
+
+// When doing bundle, if all else fails we can try to figure out which m-line a
+// given RTP packet belongs to by looking at the payload type field. This only
+// works, however, if that payload type appeared in only one m-section.
+// We figure that out here.
+/* static */
+void JsepTrack::SetUniquePayloadTypes(std::vector<JsepTrack*>& tracks) {
+  // Maps to track details if no other track contains the payload type,
+  // otherwise maps to nullptr.
+  std::map<uint16_t, JsepTrackNegotiatedDetails*> payloadTypeToDetailsMap;
+
+  for (JsepTrack* track : tracks) {
+    if (track->GetMediaType() == SdpMediaSection::kApplication) {
+      continue;
+    }
+
+    auto* details = track->GetNegotiatedDetails();
+    if (!details) {
+      // Can happen if negotiation fails on a track
+      continue;
+    }
+
+    std::vector<uint16_t> payloadTypesForTrack;
+    track->GetNegotiatedPayloadTypes(&payloadTypesForTrack);
+
+    for (uint16_t pt : payloadTypesForTrack) {
+      if (payloadTypeToDetailsMap.count(pt)) {
+        // Found in more than one track, not unique
+        payloadTypeToDetailsMap[pt] = nullptr;
+      } else {
+        payloadTypeToDetailsMap[pt] = details;
+      }
+    }
+  }
+
+  for (auto ptAndDetails : payloadTypeToDetailsMap) {
+    uint16_t uniquePt = ptAndDetails.first;
+    MOZ_ASSERT(uniquePt <= UINT8_MAX);
+    auto trackDetails = ptAndDetails.second;
+
+    if (trackDetails) {
+      trackDetails->mUniquePayloadTypes.push_back(
+          static_cast<uint8_t>(uniquePt));
+    }
+  }
+}
+
+}  // namespace mozilla