Esempio n. 1
0
void
JsepTrack::NegotiateCodecs(
    const SdpMediaSection& remote,
    std::vector<JsepCodecDescription*>* codecs,
    std::map<std::string, std::string>* formatChanges) const
{
  PtrVector<JsepCodecDescription> unnegotiatedCodecs;
  std::swap(unnegotiatedCodecs.values, *codecs);

  // Outer loop establishes the remote side's preference
  for (const std::string& fmt : remote.GetFormats()) {
    for (size_t i = 0; i < unnegotiatedCodecs.values.size(); ++i) {
      JsepCodecDescription* codec = unnegotiatedCodecs.values[i];
      if (!codec || !codec->mEnabled || !codec->Matches(fmt, remote)) {
        continue;
      }

      std::string originalFormat = codec->mDefaultPt;
      if(codec->Negotiate(fmt, remote)) {
        codecs->push_back(codec);
        unnegotiatedCodecs.values[i] = nullptr;
        if (formatChanges) {
          (*formatChanges)[originalFormat] = codec->mDefaultPt;
        }
        break;
      }
    }
  }

  // Make sure strongly preferred codecs are up front, overriding the remote
  // side's preference.
  std::stable_sort(codecs->begin(), codecs->end(), CompareCodec);

  // TODO(bug 814227): Remove this once we're ready to put multiple codecs in an
  // answer
  if (!codecs->empty()) {
    for (size_t i = 1; i < codecs->size(); ++i) {
      delete (*codecs)[i];
      (*codecs)[i] = nullptr;
    }
    codecs->resize(1);
  }
}
Esempio n. 2
0
void
JsepTrack::NegotiateCodecs(
    const SdpMediaSection& remote,
    std::vector<JsepCodecDescription*>* codecs,
    std::map<std::string, std::string>* formatChanges) const
{
  PtrVector<JsepCodecDescription> unnegotiatedCodecs;
  std::swap(unnegotiatedCodecs.values, *codecs);

  // Outer loop establishes the remote side's preference
  for (const std::string& fmt : remote.GetFormats()) {
    for (size_t i = 0; i < unnegotiatedCodecs.values.size(); ++i) {
      JsepCodecDescription* codec = unnegotiatedCodecs.values[i];
      if (!codec || !codec->mEnabled || !codec->Matches(fmt, remote)) {
        continue;
      }

      std::string originalFormat = codec->mDefaultPt;
      if(codec->Negotiate(fmt, remote)) {
        codecs->push_back(codec);
        unnegotiatedCodecs.values[i] = nullptr;
        if (formatChanges) {
          (*formatChanges)[originalFormat] = codec->mDefaultPt;
        }
        break;
      }
    }
  }

  // Find the (potential) red codec and ulpfec codec
  JsepVideoCodecDescription* red = nullptr;
  JsepVideoCodecDescription* ulpfec = nullptr;
  for (auto codec : *codecs) {
    if (codec->mName == "red") {
      red = static_cast<JsepVideoCodecDescription*>(codec);
    }
    else if (codec->mName == "ulpfec") {
      ulpfec = static_cast<JsepVideoCodecDescription*>(codec);
    }
  }
  // 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 (auto codec : *codecs) {
        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 : *codecs) {
      if (codec->mName != "red" && codec->mName != "ulpfec") {
        JsepVideoCodecDescription* videoCodec =
            static_cast<JsepVideoCodecDescription*>(codec);
        videoCodec->EnableFec();
      }
    }
  }

  // Make sure strongly preferred codecs are up front, overriding the remote
  // side's preference.
  std::stable_sort(codecs->begin(), codecs->end(), CompareCodec);

  // TODO(bug 814227): Remove this once we're ready to put multiple codecs in an
  // answer.  For now, remove all but the first codec unless the red codec
  // exists, and then we include the others per RFC 5109, section 14.2.
  if (!codecs->empty() && !red) {
    for (size_t i = 1; i < codecs->size(); ++i) {
      delete (*codecs)[i];
      (*codecs)[i] = nullptr;
    }
    codecs->resize(1);
  }
}