gst-meet/lib-gst-meet/src/jingle.rs

use std::{collections::HashMap, fmt, net::SocketAddr};

use anyhow::{anyhow, bail, Context, Result};
use futures::stream::StreamExt;
use glib::{ObjectExt, ToValue};
use gstreamer::prelude::{ElementExt, GObjectExtManualGst, GstBinExt, PadExt};
use gstreamer_rtp::{prelude::RTPHeaderExtensionExt, RTPHeaderExtension};
use nice_gst_meet as nice;
use pem::Pem;
use rand::random;
use rcgen::{Certificate, CertificateParams, PKCS_ECDSA_P256_SHA256};
use ring::digest::{digest, SHA256};
use tokio::{net::lookup_host, runtime::Handle, sync::oneshot};
use tracing::{debug, error, warn};
use uuid::Uuid;
use xmpp_parsers::{
  hashes::Algo,
  iq::Iq,
  jingle::{Action, Content, Creator, Description, Jingle, Senders, Transport},
  jingle_dtls_srtp::{Fingerprint, Setup},
  jingle_ice_udp::{self, Transport as IceUdpTransport},
  jingle_rtcp_fb::RtcpFb,
  jingle_rtp::{self, Description as RtpDescription, PayloadType, RtcpMux},
  jingle_rtp_hdrext::RtpHdrext,
  jingle_ssma::{self, Parameter},
  Jid,
};

use crate::{
  colibri::ColibriChannel,
  conference::JitsiConference,
  source::{MediaType, Source},
  util::generate_id,
};

const RTP_HDREXT_SSRC_AUDIO_LEVEL: &str = "urn:ietf:params:rtp-hdrext:ssrc-audio-level";
const RTP_HDREXT_ABS_SEND_TIME: &str = "http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time";
const RTP_HDREXT_TRANSPORT_CC: &str =
  "http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01";

const DEFAULT_STUN_PORT: u16 = 3478;
const DEFAULT_TURNS_PORT: u16 = 5349;

struct ParsedRtpDescription {
    opus_payload_type: Option<u8>,
    opus_rtcp_fbs: Option<Vec<RtcpFb>>,
    h264_payload_type: Option<u8>,
    h264_rtx_payload_type: Option<u8>,
    h264_rtcp_fbs: Option<Vec<RtcpFb>>,
    vp8_payload_type: Option<u8>,
    vp8_rtx_payload_type: Option<u8>,
    vp8_rtcp_fbs: Option<Vec<RtcpFb>>,
    vp9_payload_type: Option<u8>,
    vp9_rtx_payload_type: Option<u8>,
    vp9_rtcp_fbs: Option<Vec<RtcpFb>>,
    audio_hdrext_ssrc_audio_level: Option<u8>,
    audio_hdrext_transport_cc: Option<u8>,
    video_hdrext_abs_send_time: Option<u8>,
    video_hdrext_transport_cc: Option<u8>,
}

pub(crate) struct JingleSession {
  pipeline: gstreamer::Pipeline,
  audio_sink_element: gstreamer::Element,
  video_sink_element: gstreamer::Element,
  remote_ssrc_map: HashMap<u32, Source>,
  _ice_agent: nice::Agent,
  pub(crate) accept_iq_id: Option<String>,
  pub(crate) colibri_url: Option<String>,
  pub(crate) colibri_channel: Option<ColibriChannel>,
  pipeline_state_null_rx: oneshot::Receiver<()>,
}

impl fmt::Debug for JingleSession {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
    f.debug_struct("JingleSession").finish()
  }
}

impl JingleSession {
  pub(crate) fn pipeline(&self) -> gstreamer::Pipeline {
    self.pipeline.clone()
  }

  pub(crate) fn audio_sink_element(&self) -> gstreamer::Element {
    self.audio_sink_element.clone()
  }

  pub(crate) fn video_sink_element(&self) -> gstreamer::Element {
    self.video_sink_element.clone()
  }

  pub(crate) fn pause_all_sinks(&self) {
    if let Some(rtpbin) = self.pipeline.by_name("rtpbin") {
      rtpbin.foreach_src_pad(|_, pad| {
        let pad_name: String = pad.property("name").unwrap().get().unwrap();
        if pad_name.starts_with("recv_rtp_src_0_") {
          if let Some(peer_pad) = pad.peer() {
            if let Some(element) = peer_pad.parent_element() {
              element.set_state(gstreamer::State::Paused).unwrap();
            }
          }
        }
        true
      });
    }
  }

  pub(crate) async fn pipeline_stopped(self) -> Result<()> {
    Ok(self.pipeline_state_null_rx.await?)
  }

  fn parse_rtp_description(description: &RtpDescription, remote_ssrc_map: &mut HashMap<u32, Source>) -> Result<Option<ParsedRtpDescription>> {
    let mut opus_payload_type = None;
    let mut opus_rtcp_fbs = None;
    let mut h264_payload_type = None;
    let mut h264_rtx_payload_type = None;
    let mut h264_rtcp_fbs = None;
    let mut vp8_payload_type = None;
    let mut vp8_rtx_payload_type = None;
    let mut vp8_rtcp_fbs = None;
    let mut vp9_payload_type = None;
    let mut vp9_rtx_payload_type = None;
    let mut vp9_rtcp_fbs = None;
    let mut audio_hdrext_ssrc_audio_level = None;
    let mut audio_hdrext_transport_cc = None;
    let mut video_hdrext_abs_send_time = None;
    let mut video_hdrext_transport_cc = None;

    if description.media == "audio" {
      opus_payload_type = description
        .payload_types
        .iter()
        .find(|pt| pt.name.as_deref() == Some("opus"))
        .map(|pt| pt.id);
      opus_rtcp_fbs = description
        .payload_types
        .iter()
        .find(|pt| pt.name.as_deref() == Some("opus"))
        .map(|pt| pt.rtcp_fbs.clone());
      audio_hdrext_ssrc_audio_level = description
        .hdrexts
        .iter()
        .find(|hdrext| hdrext.uri == RTP_HDREXT_SSRC_AUDIO_LEVEL)
        .map(|hdrext| hdrext.id.parse::<u8>())
        .transpose()?;
      audio_hdrext_transport_cc = description
        .hdrexts
        .iter()
        .find(|hdrext| hdrext.uri == RTP_HDREXT_TRANSPORT_CC)
        .map(|hdrext| hdrext.id.parse::<u8>())
        .transpose()?;
    }
    else if description.media == "video" {
      h264_payload_type = description
        .payload_types
        .iter()
        .find(|pt| pt.name.as_deref() == Some("H264"))
        .map(|pt| pt.id);
      h264_rtx_payload_type = description
        .payload_types
        .iter()
        .find(|pt| {
          pt.name.as_deref() == Some("rtx")
            && pt.parameters.iter().any(|param| {
              param.name == "apt"
                && param.value
                  == h264_payload_type
                    .map(|pt| pt.to_string())
                    .unwrap_or_default()
            })
        })
        .map(|pt| pt.id);
      h264_rtcp_fbs = description
        .payload_types
        .iter()
        .find(|pt| pt.name.as_deref() == Some("H264"))
        .map(|pt| pt.rtcp_fbs.clone());
      vp8_payload_type = description
        .payload_types
        .iter()
        .find(|pt| pt.name.as_deref() == Some("VP8"))
        .map(|pt| pt.id);
      vp8_rtx_payload_type = description
        .payload_types
        .iter()
        .find(|pt| {
          pt.name.as_deref() == Some("rtx")
            && pt.parameters.iter().any(|param| {
              param.name == "apt"
                && param.value
                  == vp8_payload_type
                    .map(|pt| pt.to_string())
                    .unwrap_or_default()
            })
        })
        .map(|pt| pt.id);
      vp8_rtcp_fbs = description
        .payload_types
        .iter()
        .find(|pt| pt.name.as_deref() == Some("VP8"))
        .map(|pt| pt.rtcp_fbs.clone());
      vp9_payload_type = description
        .payload_types
        .iter()
        .find(|pt| pt.name.as_deref() == Some("VP9"))
        .map(|pt| pt.id);
      vp9_rtx_payload_type = description
        .payload_types
        .iter()
        .find(|pt| {
          pt.name.as_deref() == Some("rtx")
            && pt.parameters.iter().any(|param| {
              param.name == "apt"
                && param.value
                  == vp9_payload_type
                    .map(|pt| pt.to_string())
                    .unwrap_or_default()
            })
        })
        .map(|pt| pt.id);
      vp9_rtcp_fbs = description
        .payload_types
        .iter()
        .find(|pt| pt.name.as_deref() == Some("VP9"))
        .map(|pt| pt.rtcp_fbs.clone());
      video_hdrext_abs_send_time = description
        .hdrexts
        .iter()
        .find(|hdrext| hdrext.uri == RTP_HDREXT_ABS_SEND_TIME)
        .map(|hdrext| hdrext.id.parse::<u8>())
        .transpose()?;
      video_hdrext_transport_cc = description
        .hdrexts
        .iter()
        .find(|hdrext| hdrext.uri == RTP_HDREXT_TRANSPORT_CC)
        .map(|hdrext| hdrext.id.parse::<u8>())
        .transpose()?;
    }
    else {
      debug!("skipping media: {}", description.media);
      return Ok(None);
    }

    for ssrc in &description.ssrcs {
      let owner = ssrc
        .info
        .as_ref()
        .context("missing ssrc-info")?
        .owner
        .clone();

      debug!("adding ssrc to remote_ssrc_map: {:?}", ssrc);
      remote_ssrc_map.insert(
        ssrc.id.parse()?,
        Source {
          ssrc: ssrc.id.parse()?,
          participant_id: if owner == "jvb" {
            None
          }
          else {
            Some(
              owner
                .split('/')
                .nth(1)
                .context("invalid ssrc-info owner")?
                .to_owned(),
            )
          },
          media_type: if description.media == "audio" {
            MediaType::Audio
          }
          else {
            MediaType::Video
          },
        },
      );
    }
    Ok(Some(ParsedRtpDescription {
        opus_payload_type,
        opus_rtcp_fbs,
        h264_payload_type,
        h264_rtx_payload_type,
        h264_rtcp_fbs,
        vp8_payload_type,
        vp8_rtx_payload_type,
        vp8_rtcp_fbs,
        vp9_payload_type,
        vp9_rtx_payload_type,
        vp9_rtcp_fbs,
        audio_hdrext_ssrc_audio_level,
        audio_hdrext_transport_cc,
        video_hdrext_abs_send_time,
        video_hdrext_transport_cc,
    }))
  }

  pub(crate) async fn initiate(conference: &JitsiConference, jingle: Jingle) -> Result<Self> {
    let initiator = jingle
      .initiator
      .as_ref()
      .ok_or_else(|| anyhow!("session-initiate with no initiator"))?
      .clone();

    debug!("Received Jingle session-initiate from {}", initiator);

    let mut ice_remote_candidates = None;
    let mut ice_remote_ufrag = None;
    let mut ice_remote_pwd = None;
    let mut dtls_fingerprint = None;
    let mut opus_payload_type = None;
    let mut opus_rtcp_fbs = None;
    let mut h264_payload_type = None;
    let mut h264_rtx_payload_type = None;
    let mut h264_rtcp_fbs = None;
    let mut vp8_payload_type = None;
    let mut vp8_rtx_payload_type = None;
    let mut vp8_rtcp_fbs = None;
    let mut vp9_payload_type = None;
    let mut vp9_rtx_payload_type = None;
    let mut vp9_rtcp_fbs = None;
    let mut audio_hdrext_ssrc_audio_level = None;
    let mut audio_hdrext_transport_cc = None;
    let mut video_hdrext_abs_send_time = None;
    let mut video_hdrext_transport_cc = None;
    let mut colibri_url = None;

    let mut remote_ssrc_map = HashMap::new();

    for content in &jingle.contents {
      if let Some(Description::Rtp(description)) = &content.description {
        if let Some(description) = JingleSession::parse_rtp_description(description, &mut remote_ssrc_map)? {
          opus_payload_type = opus_payload_type.or(description.opus_payload_type);
          opus_rtcp_fbs = opus_rtcp_fbs.or(description.opus_rtcp_fbs);
          h264_payload_type = h264_payload_type.or(description.h264_payload_type);
          h264_rtx_payload_type = h264_rtx_payload_type.or(description.h264_rtx_payload_type);
          h264_rtcp_fbs = h264_rtcp_fbs.or(description.h264_rtcp_fbs);
          vp8_payload_type = vp8_payload_type.or(description.vp8_payload_type);
          vp8_rtx_payload_type = vp8_rtx_payload_type.or(description.vp8_rtx_payload_type);
          vp8_rtcp_fbs = vp8_rtcp_fbs.or(description.vp8_rtcp_fbs);
          vp9_payload_type = vp9_payload_type.or(description.vp9_payload_type);
          vp9_rtx_payload_type = vp9_rtx_payload_type.or(description.vp9_rtx_payload_type);
          vp9_rtcp_fbs = vp9_rtcp_fbs.or(description.vp9_rtcp_fbs);
          audio_hdrext_ssrc_audio_level = audio_hdrext_ssrc_audio_level.or(description.audio_hdrext_ssrc_audio_level);
          audio_hdrext_transport_cc = audio_hdrext_transport_cc.or(description.audio_hdrext_transport_cc);
          video_hdrext_abs_send_time = video_hdrext_abs_send_time.or(description.video_hdrext_abs_send_time);
          video_hdrext_transport_cc = video_hdrext_transport_cc.or(description.video_hdrext_transport_cc);
        }
      }

      if let Some(Transport::IceUdp(transport)) = &content.transport {
        if !transport.candidates.is_empty() {
          ice_remote_candidates = Some(transport.candidates.clone());
        }
        if let Some(ufrag) = &transport.ufrag {
          ice_remote_ufrag = Some(ufrag.to_owned());
        }
        if let Some(pwd) = &transport.pwd {
          ice_remote_pwd = Some(pwd.to_owned());
        }
        if let Some(fingerprint) = &transport.fingerprint {
          if fingerprint.hash != Algo::Sha_256 {
            bail!("unsupported fingerprint hash: {:?}", fingerprint.hash);
          }
          dtls_fingerprint = Some(fingerprint.value.clone());
        }
        if let Some(websocket) = &transport.web_socket {
          colibri_url = Some(websocket.url.clone());
        }
      }
    }

    if let Some(remote_fingerprint) = dtls_fingerprint {
      warn!(
        "Remote DTLS fingerprint (verification not implemented yet): {:?}",
        remote_fingerprint
      );
    }

    let mut dtls_cert_params = CertificateParams::new(vec!["gst-meet".to_owned()]);
    dtls_cert_params.alg = &PKCS_ECDSA_P256_SHA256;
    let dtls_cert = Certificate::from_params(dtls_cert_params)?;
    let dtls_cert_der = dtls_cert.serialize_der()?;
    let fingerprint = digest(&SHA256, &dtls_cert_der).as_ref().to_vec();
    let fingerprint_str =
      itertools::join(fingerprint.iter().map(|byte| format!("{:X}", byte)), ":");
    let dtls_cert_pem = pem::encode(&Pem {
      tag: "CERTIFICATE".to_string(),
      contents: dtls_cert_der,
    });
    let dtls_private_key_pem = pem::encode(&Pem {
      tag: "PRIVATE KEY".to_string(),
      contents: dtls_cert.serialize_private_key_der(),
    });
    debug!("Local DTLS certificate:\n{}", dtls_cert_pem);
    debug!("Local DTLS fingerprint: {}", fingerprint_str);

    let audio_ssrc: u32 = random();
    let video_ssrc: u32 = random();
    let video_rtx_ssrc: u32 = random();

    debug!("audio SSRC: {}", audio_ssrc);
    debug!("video SSRC: {}", video_ssrc);
    debug!("video RTX SSRC: {}", video_rtx_ssrc);

    let ice_agent = nice::Agent::new(&conference.glib_main_context, nice::Compatibility::Rfc5245);
    ice_agent.set_ice_tcp(false);
    ice_agent.set_upnp(false);
    let ice_stream_id = ice_agent.add_stream(1);
    let ice_component_id = 1;

    let maybe_stun = conference
      .external_services
      .iter()
      .find(|svc| svc.r#type == "stun");

    let stun_addr = if let Some(stun) = maybe_stun {
      lookup_host(format!(
        "{}:{}",
        stun.host,
        stun.port.unwrap_or(DEFAULT_STUN_PORT)
      ))
      .await?
      .next()
    }
    else {
      None
    };
    debug!("STUN address: {:?}", stun_addr);

    if let Some((stun_addr, stun_port)) = stun_addr.map(|sa| (sa.ip().to_string(), sa.port())) {
      ice_agent.set_stun_server(Some(&stun_addr));
      ice_agent.set_stun_server_port(stun_port as u32);
    }

    let maybe_turn = conference
      .external_services
      .iter()
      .find(|svc| svc.r#type == "turns");

    if let Some(turn_server) = maybe_turn {
      let maybe_addr = lookup_host(format!(
        "{}:{}",
        turn_server.host,
        turn_server.port.unwrap_or(DEFAULT_TURNS_PORT)
      ))
      .await?
      .next();

      if let Some(addr) = maybe_addr {
        debug!("TURN address: {:?}", addr);
        ice_agent.set_relay_info(
          ice_stream_id,
          ice_component_id,
          &addr.ip().to_string(),
          addr.port() as u32,
          turn_server.username.as_deref().unwrap_or_default(),
          turn_server.password.as_deref().unwrap_or_default(),
          nice::RelayType::Tls,
        );
      }
    }

    if !ice_agent.attach_recv(
      ice_stream_id,
      ice_component_id,
      &conference.glib_main_context,
      |_, _, _, s| debug!("ICE nice_agent_attach_recv cb: {}", s),
    ) {
      warn!("nice_agent_attach_recv failed");
    }

    debug!("ice_agent={:?}", ice_agent);
    debug!("ice_stream_id={}", ice_stream_id);
    debug!("ice_component_id={}", ice_component_id);

    let (ice_local_ufrag, ice_local_pwd) = ice_agent
      .local_credentials(ice_stream_id)
      .context("no local ICE credentials")?;

    if let (Some(ufrag), Some(pwd)) = (&ice_remote_ufrag, &ice_remote_pwd) {
      debug!("setting ICE remote credentials");
      if !ice_agent.set_remote_credentials(ice_stream_id, ufrag, pwd) {
        warn!("nice_agent_set_remote_candidates failed");
      }
    }

    ice_agent.connect_candidate_gathering_done(move |_agent, candidates| {
      debug!("ICE candidate-gathering-done {:?}", candidates);
    });

    debug!("gathering ICE candidates");
    if !ice_agent.gather_candidates(ice_stream_id) {
      warn!("nice_agent_gather_candidates failed");
    }

    if let (Some(ufrag), Some(pwd), Some(remote_candidates)) =
      (&ice_remote_ufrag, &ice_remote_pwd, &ice_remote_candidates)
    {
      debug!("setting ICE remote candidates: {:?}", remote_candidates);
      let remote_candidates: Vec<_> = remote_candidates
        .iter()
        .map(|c| {
          let mut candidate = nice::Candidate::new(match c.type_ {
            jingle_ice_udp::Type::Host => nice::CandidateType::Host,
            jingle_ice_udp::Type::Prflx => nice::CandidateType::PeerReflexive,
            jingle_ice_udp::Type::Srflx => nice::CandidateType::ServerReflexive,
            jingle_ice_udp::Type::Relay => nice::CandidateType::Relayed,
          });
          candidate.set_stream_id(ice_stream_id);
          candidate.set_component_id(c.component as u32);
          candidate.set_foundation(&c.foundation);
          candidate.set_addr(SocketAddr::new(c.ip, c.port));
          candidate.set_priority(c.priority);
          candidate.set_username(ufrag);
          candidate.set_password(pwd);
          debug!("candidate: {:?}", candidate);
          candidate
        })
        .collect();
      let candidate_refs: Vec<_> = remote_candidates.iter().collect();
      let res = ice_agent.set_remote_candidates(ice_stream_id, ice_component_id, &candidate_refs);
      if res < remote_candidates.len() as i32 {
        warn!("some remote candidates failed to add: {}", res);
      }
    }

    debug!("building gstreamer pipeline");

    let pipeline = gstreamer::Pipeline::new(None);

    let rtpbin = gstreamer::ElementFactory::make("rtpbin", Some("rtpbin"))?;
    rtpbin.set_property_from_str("rtp-profile", "savpf");
    rtpbin.set_property("autoremove", true)?;
    pipeline.add(&rtpbin)?;

    let nicesrc = gstreamer::ElementFactory::make("nicesrc", None)?;
    nicesrc.set_property("stream", ice_stream_id)?;
    nicesrc.set_property("component", ice_component_id)?;
    nicesrc.set_property("agent", &ice_agent)?;
    pipeline.add(&nicesrc)?;

    let nicesink = gstreamer::ElementFactory::make("nicesink", None)?;
    nicesink.set_property("stream", ice_stream_id)?;
    nicesink.set_property("component", ice_component_id)?;
    nicesink.set_property("agent", &ice_agent)?;
    pipeline.add(&nicesink)?;

    let dtls_srtp_connection_id = "gst-meet";

    let dtlssrtpenc = gstreamer::ElementFactory::make("dtlssrtpenc", None)?;
    dtlssrtpenc.set_property("connection-id", dtls_srtp_connection_id)?;
    dtlssrtpenc.set_property("is-client", true)?;
    pipeline.add(&dtlssrtpenc)?;

    let dtlssrtpdec = gstreamer::ElementFactory::make("dtlssrtpdec", None)?;
    dtlssrtpdec.set_property("connection-id", dtls_srtp_connection_id)?;
    dtlssrtpdec.set_property(
      "pem",
      format!("{}\n{}", dtls_cert_pem, dtls_private_key_pem),
    )?;
    pipeline.add(&dtlssrtpdec)?;

    rtpbin.connect("request-pt-map", false, move |values| {
      let f = || {
        debug!("rtpbin request-pt-map {:?}", values);
        let pt = values[2].get::<u32>()? as u8;
        let mut caps = gstreamer::Caps::builder("application/x-rtp");
        if Some(pt) == opus_payload_type {
          caps = caps
            .field("media", "audio")
            .field("encoding-name", "OPUS")
            .field("clock-rate", 48000);
          if let Some(hdrext) = audio_hdrext_ssrc_audio_level {
            caps = caps.field(&format!("extmap-{}", hdrext), RTP_HDREXT_SSRC_AUDIO_LEVEL);
          }
          if let Some(hdrext) = audio_hdrext_transport_cc {
            caps = caps.field(&format!("extmap-{}", hdrext), &RTP_HDREXT_TRANSPORT_CC);
          }
          Ok::<_, anyhow::Error>(Some(caps.build()))
        }
        else if Some(pt) == h264_payload_type
          || Some(pt) == vp8_payload_type
          || Some(pt) == vp9_payload_type
        {
          caps = caps
            .field("media", "video")
            .field("clock-rate", 90000)
            .field(
              "encoding-name",
              if Some(pt) == h264_payload_type {
                "H264"
              }
              else if Some(pt) == vp8_payload_type {
                "VP8"
              }
              else if Some(pt) == vp9_payload_type {
                "VP9"
              }
              else {
                unreachable!()
              },
            );
          // if let Some(hdrext) = video_hdrext_abs_send_time {
          //   caps = caps.field(&format!("extmap-{}", hdrext), &RTP_HDREXT_ABS_SEND_TIME);
          // }
          if let Some(hdrext) = video_hdrext_transport_cc {
            caps = caps.field(&format!("extmap-{}", hdrext), &RTP_HDREXT_TRANSPORT_CC);
          }
          Ok(Some(caps.build()))
        }
        else if Some(pt) == vp8_rtx_payload_type
          || Some(pt) == vp9_rtx_payload_type
          || Some(pt) == h264_rtx_payload_type
        {
          caps = caps
            .field("media", "video")
            .field("clock-rate", 90000)
            .field("encoding-name", "RTX")
            .field(
              "apt",
              if Some(pt) == vp8_rtx_payload_type {
                vp8_payload_type.context("missing VP8 payload type")?
              }
              else if Some(pt) == vp9_rtx_payload_type {
                vp9_payload_type.context("missing VP9 payload type")?
              }
              else if Some(pt) == h264_rtx_payload_type {
                h264_payload_type.context("missing H264 payload type")?
              }
              else {
                unreachable!()
              },
            );
          Ok(Some(caps.build()))
        }
        else {
          warn!("unknown payload type: {}", pt);
          Ok(None)
        }
      };
      match f() {
        Ok(Some(caps)) => {
          debug!("mapped pt to caps: {:?}", caps);
          Some(caps.to_value())
        },
        Ok(None) => None,
        Err(e) => {
          error!("handling request-pt-map: {:?}", e);
          None
        },
      }
    })?;

    let handle = Handle::current();
    let jingle_session = conference.jingle_session.clone();
    rtpbin.connect("new-jitterbuffer", false, move |values| {
      let handle = handle.clone();
      let jingle_session = jingle_session.clone();
      let f = move || {
        let rtpjitterbuffer: gstreamer::Element = values[1].get()?;
        let session: u32 = values[2].get()?;
        let ssrc: u32 = values[3].get()?;
        debug!(
          "new jitterbuffer created for session {} ssrc {}",
          session, ssrc
        );

        let source = handle.block_on(async move {
          Ok::<_, anyhow::Error>(
            jingle_session
              .lock()
              .await
              .as_ref()
              .context("not connected (no jingle session)")?
              .remote_ssrc_map
              .get(&ssrc)
              .context(format!("unknown ssrc: {}", ssrc))?
              .clone(),
          )
        })?;
        debug!("jitterbuffer is for remote source: {:?}", source);
        if source.media_type == MediaType::Video && source.participant_id.is_some() {
          debug!("enabling RTX for ssrc {}", ssrc);
          rtpjitterbuffer.set_property("do-retransmission", true)?;
        }
        Ok::<_, anyhow::Error>(())
      };
      if let Err(e) = f() {
        warn!("new-jitterbuffer: {:?}", e);
      }
      None
    })?;

    rtpbin.connect("request-aux-sender", false, move |values| {
      let f = move || {
        let session: u32 = values[1].get()?;
        debug!("creating RTX sender for session {}", session);
        let mut pt_map = gstreamer::Structure::builder("application/x-rtp-pt-map");
        let mut ssrc_map = gstreamer::Structure::builder("application/x-rtp-ssrc-map");
        if let (Some(pt), Some(rtx_pt)) = (vp8_payload_type, vp8_rtx_payload_type) {
          pt_map = pt_map.field(&pt.to_string(), &(rtx_pt as u32));
        }
        if let (Some(pt), Some(rtx_pt)) = (vp9_payload_type, vp9_rtx_payload_type) {
          pt_map = pt_map.field(&pt.to_string(), &(rtx_pt as u32));
        }
        if let (Some(pt), Some(rtx_pt)) = (h264_payload_type, h264_rtx_payload_type) {
          pt_map = pt_map.field(&pt.to_string(), &(rtx_pt as u32));
        }
        ssrc_map = ssrc_map.field(&video_ssrc.to_string(), &(video_rtx_ssrc as u32));
        let bin = gstreamer::Bin::new(None);
        let rtx_sender = gstreamer::ElementFactory::make("rtprtxsend", None)?;
        rtx_sender.set_property("payload-type-map", pt_map.build())?;
        rtx_sender.set_property("ssrc-map", ssrc_map.build())?;
        bin.add(&rtx_sender)?;
        bin.add_pad(&gstreamer::GhostPad::with_target(
          Some(&format!("src_{}", session)),
          &rtx_sender
            .static_pad("src")
            .context("rtprtxsend has no src pad")?,
        )?)?;
        bin.add_pad(&gstreamer::GhostPad::with_target(
          Some(&format!("sink_{}", session)),
          &rtx_sender
            .static_pad("sink")
            .context("rtprtxsend has no sink pad")?,
        )?)?;
        Ok::<_, anyhow::Error>(Some(bin.to_value()))
      };
      match f() {
        Ok(o) => o,
        Err(e) => {
          warn!("request-aux-sender: {:?}", e);
          None
        },
      }
    })?;

    rtpbin.connect("request-aux-receiver", false, move |values| {
      let f = move || {
        let session: u32 = values[1].get()?;
        debug!("creating RTX receiver for session {}", session);
        let mut pt_map = gstreamer::Structure::builder("application/x-rtp-pt-map");
        if let (Some(pt), Some(rtx_pt)) = (vp8_payload_type, vp8_rtx_payload_type) {
          pt_map = pt_map.field(&pt.to_string(), &(rtx_pt as u32));
        }
        if let (Some(pt), Some(rtx_pt)) = (vp9_payload_type, vp9_rtx_payload_type) {
          pt_map = pt_map.field(&pt.to_string(), &(rtx_pt as u32));
        }
        if let (Some(pt), Some(rtx_pt)) = (h264_payload_type, h264_rtx_payload_type) {
          pt_map = pt_map.field(&pt.to_string(), &(rtx_pt as u32));
        }
        let bin = gstreamer::Bin::new(None);
        let rtx_receiver = gstreamer::ElementFactory::make("rtprtxreceive", None)?;
        rtx_receiver.set_property("payload-type-map", pt_map.build())?;
        bin.add(&rtx_receiver)?;
        bin.add_pad(&gstreamer::GhostPad::with_target(
          Some(&format!("src_{}", session)),
          &rtx_receiver
            .static_pad("src")
            .context("rtprtxreceive has no src pad")?,
        )?)?;
        bin.add_pad(&gstreamer::GhostPad::with_target(
          Some(&format!("sink_{}", session)),
          &rtx_receiver
            .static_pad("sink")
            .context("rtprtxreceive has no sink pad")?,
        )?)?;
        Ok::<_, anyhow::Error>(Some(bin.to_value()))
      };
      match f() {
        Ok(o) => o,
        Err(e) => {
          warn!("request-aux-receiver: {:?}", e);
          None
        },
      }
    })?;

    {
      let handle = Handle::current();
      let conference = conference.clone();
      let pipeline = pipeline.clone();
      let rtpbin_ = rtpbin.clone();
      rtpbin.connect("pad-added", false, move |values| {
        let rtpbin = &rtpbin_;
        let f = || {
          debug!("rtpbin pad-added {:?}", values);
          let pad: gstreamer::Pad = values[1].get()?;
          let pad_name: String = pad.property("name")?.get()?;
          if pad_name.starts_with("recv_rtp_src_0_") {
            let mut parts = pad_name.split('_').skip(4);
            let ssrc: u32 = parts.next().context("malformed pad name")?.parse()?;
            let pt: u8 = parts.next().context("malformed pad name")?.parse()?;
            let source = handle.block_on(async {
              Ok::<_, anyhow::Error>(
                conference
                  .jingle_session
                  .lock()
                  .await
                  .as_ref()
                  .context("not connected (no jingle session)")?
                  .remote_ssrc_map
                  .get(&ssrc)
                  .context(format!("unknown ssrc: {}", ssrc))?
                  .clone(),
              )
            })?;

            debug!("pad added for remote source: {:?}", source);

            let source_element = match source.media_type {
              MediaType::Audio => {
                if Some(pt) == opus_payload_type {
                  gstreamer::ElementFactory::make("rtpopusdepay", None)?
                }
                else {
                  bail!("received audio with unsupported PT {}", pt);
                }
              },
              MediaType::Video => {
                if Some(pt) == h264_payload_type {
                  let element = gstreamer::ElementFactory::make("rtph264depay", None)?;
                  element.set_property("request-keyframe", true)?;
                  element
                }
                else if Some(pt) == vp8_payload_type {
                  let element = gstreamer::ElementFactory::make("rtpvp8depay", None)?;
                  element.set_property("request-keyframe", true)?;
                  element
                }
                else if Some(pt) == vp9_payload_type {
                  let element = gstreamer::ElementFactory::make("rtpvp9depay", None)?;
                  element.set_property("request-keyframe", true)?;
                  element
                }
                else {
                  bail!("received video with unsupported PT {}", pt);
                }
              },
            };

            source_element.set_property("auto-header-extension", false)?;
            source_element.connect("request-extension", false, move |values| {
              let f = || {
                let ext_id: u32 = values[1].get()?;
                let ext_uri: String = values[2].get()?;
                debug!("depayloader requested extension: {} {}", ext_id, ext_uri);
                let hdrext = RTPHeaderExtension::create_from_uri(&ext_uri)
                  .context("failed to create hdrext")?;
                hdrext.set_id(ext_id);
                if ext_uri == RTP_HDREXT_ABS_SEND_TIME {}
                if ext_uri == RTP_HDREXT_SSRC_AUDIO_LEVEL {
                }
                else if ext_uri == RTP_HDREXT_TRANSPORT_CC {
                }
                else {
                  bail!("unknown rtp hdrext: {}", ext_uri);
                };
                Ok::<_, anyhow::Error>(hdrext)
              };
              match f() {
                Ok(hdrext) => Some(hdrext.to_value()),
                Err(e) => {
                  warn!("request-extension: {:?}", e);
                  None
                },
              }
            })?;
            pipeline
              .add(&source_element)
              .context("failed to add depayloader to pipeline")?;
            source_element.sync_state_with_parent()?;
            debug!("created depayloader");
            rtpbin
              .link_pads(Some(&pad_name), &source_element, None)
              .context(format!("failed to link rtpbin.{} to depayloader", pad_name))?;
            debug!("linked rtpbin.{} to depayloader", pad_name);

            let src_pad = source_element
              .static_pad("src")
              .context("depayloader has no src pad")?;

            if let Some(participant_id) = source.participant_id {
              handle.block_on(conference.ensure_participant(&participant_id))?;
              if let Some(participant_bin) =
                pipeline.by_name(&format!("participant_{}", participant_id))
              {
                let sink_pad_name = match source.media_type {
                  MediaType::Audio => "audio",
                  MediaType::Video => "video",
                };
                if let Some(sink_pad) = participant_bin.static_pad(sink_pad_name) {
                  debug!("linking depayloader to participant bin");
                  src_pad.link(&sink_pad)?;
                }
                else {
                  warn!(
                    "no {} sink pad in {} participant bin",
                    sink_pad_name, participant_id
                  );
                }
              }
              else {
                debug!("no participant bin for {}", participant_id);
              }
            }
            else {
              debug!("not looking for participant bin, source is owned by JVB");
            }

            if !src_pad.is_linked() {
              debug!("nothing linked to depayloader, adding fakesink");
              let fakesink = gstreamer::ElementFactory::make("fakesink", None)?;
              pipeline.add(&fakesink)?;
              fakesink.sync_state_with_parent()?;
              source_element.link(&fakesink)?;
            }

            gstreamer::debug_bin_to_dot_file(
              &pipeline,
              gstreamer::DebugGraphDetails::ALL,
              &format!("ssrc-added-{}", ssrc),
            );

            Ok::<_, anyhow::Error>(())
          }
          else {
            Ok(())
          }
        };
        if let Err(e) = f() {
          error!("handling pad-added: {:?}", e);
        }
        None
      })?;
    }

    let audio_sink_element = gstreamer::ElementFactory::make("rtpopuspay", None)?;
    audio_sink_element.set_property(
      "pt",
      opus_payload_type.context("no opus payload type in jingle session-initiate")? as u32,
    )?;
    audio_sink_element.set_property("min-ptime", 10i64 * 1000 * 1000)?;
    audio_sink_element.set_property("ssrc", audio_ssrc)?;
    if audio_sink_element.has_property("auto-header-extension", None) {
      audio_sink_element.set_property("auto-header-extension", false)?;
      audio_sink_element.connect("request-extension", false, move |values| {
        let f = || {
          let ext_id: u32 = values[1].get()?;
          let ext_uri: String = values[2].get()?;
          debug!(
            "audio payloader requested extension: {} {}",
            ext_id, ext_uri
          );
          let hdrext =
            RTPHeaderExtension::create_from_uri(&ext_uri).context("failed to create hdrext")?;
          hdrext.set_id(ext_id);
          if ext_uri == RTP_HDREXT_ABS_SEND_TIME {
          }
          else if ext_uri == RTP_HDREXT_SSRC_AUDIO_LEVEL {
          }
          else if ext_uri == RTP_HDREXT_TRANSPORT_CC {
            // hdrext.set_property("n-streams", 2u32)?;
          }
          else {
            bail!("unknown rtp hdrext: {}", ext_uri);
          }
          Ok::<_, anyhow::Error>(hdrext)
        };
        match f() {
          Ok(hdrext) => Some(hdrext.to_value()),
          Err(e) => {
            warn!("request-extension: {:?}", e);
            None
          },
        }
      })?;
    }
    else {
      debug!("audio payloader: no rtp header extension support");
    }
    pipeline.add(&audio_sink_element)?;

    let video_sink_element = match conference.config.video_codec.as_str() {
      "h264" => {
        let element = gstreamer::ElementFactory::make("rtph264pay", None)?;
        element.set_property(
          "pt",
          h264_payload_type.context("no h264 payload type in jingle session-initiate")? as u32,
        )?;
        element.set_property_from_str("aggregate-mode", "zero-latency");
        element
      },
      "vp8" => {
        let element = gstreamer::ElementFactory::make("rtpvp8pay", None)?;
        element.set_property(
          "pt",
          vp8_payload_type.context("no vp8 payload type in jingle session-initiate")? as u32,
        )?;
        element.set_property_from_str("picture-id-mode", "15-bit");
        element
      },
      "vp9" => {
        let element = gstreamer::ElementFactory::make("rtpvp9pay", None)?;
        element.set_property(
          "pt",
          vp9_payload_type.context("no vp9 payload type in jingle session-initiate")? as u32,
        )?;
        element.set_property_from_str("picture-id-mode", "15-bit");
        element
      },
      other => bail!("unsupported video codec: {}", other),
    };
    video_sink_element.set_property("ssrc", video_ssrc)?;
    if video_sink_element.has_property("auto-header-extension", None) {
      video_sink_element.set_property("auto-header-extension", false)?;
      video_sink_element.connect("request-extension", false, move |values| {
        let f = || {
          let ext_id: u32 = values[1].get()?;
          let ext_uri: String = values[2].get()?;
          debug!(
            "video payloader requested extension: {} {}",
            ext_id, ext_uri
          );
          let hdrext =
            RTPHeaderExtension::create_from_uri(&ext_uri).context("failed to create hdrext")?;
          hdrext.set_id(ext_id);
          if ext_uri == RTP_HDREXT_ABS_SEND_TIME {
          }
          else if ext_uri == RTP_HDREXT_TRANSPORT_CC {
            // hdrext.set_property("n-streams", 2u32)?;
          }
          else {
            bail!("unknown rtp hdrext: {}", ext_uri);
          }
          Ok::<_, anyhow::Error>(hdrext)
        };
        match f() {
          Ok(hdrext) => Some(hdrext.to_value()),
          Err(e) => {
            warn!("request-extension: {:?}", e);
            None
          },
        }
      })?;
    }
    else {
      debug!("video payloader: no rtp header extension support");
    }
    pipeline.add(&video_sink_element)?;

    let mut audio_caps = gstreamer::Caps::builder("application/x-rtp");
    if let Some(hdrext) = audio_hdrext_ssrc_audio_level {
      audio_caps = audio_caps.field(&format!("extmap-{}", hdrext), RTP_HDREXT_SSRC_AUDIO_LEVEL);
    }
    if let Some(hdrext) = audio_hdrext_transport_cc {
      audio_caps = audio_caps.field(&format!("extmap-{}", hdrext), RTP_HDREXT_TRANSPORT_CC);
    }
    let audio_capsfilter = gstreamer::ElementFactory::make("capsfilter", None)?;
    audio_capsfilter.set_property("caps", audio_caps.build())?;
    pipeline.add(&audio_capsfilter)?;

    let mut video_caps = gstreamer::Caps::builder("application/x-rtp");
    // if let Some(hdrext) = video_hdrext_abs_send_time {
    //   video_caps = video_caps.field(&format!("extmap-{}", hdrext), &RTP_HDREXT_ABS_SEND_TIME);
    // }
    if let Some(hdrext) = video_hdrext_transport_cc {
      video_caps = video_caps.field(&format!("extmap-{}", hdrext), &RTP_HDREXT_TRANSPORT_CC);
    }
    let video_capsfilter = gstreamer::ElementFactory::make("capsfilter", None)?;
    video_capsfilter.set_property("caps", video_caps.build())?;
    pipeline.add(&video_capsfilter)?;

    let rtpfunnel = gstreamer::ElementFactory::make("rtpfunnel", None)?;
    pipeline.add(&rtpfunnel)?;

    debug!("linking video payloader -> rtpfunnel");
    video_sink_element.link(&video_capsfilter)?;
    video_capsfilter.link(&rtpfunnel)?;

    debug!("linking audio payloader -> rtpfunnel");
    audio_sink_element.link(&audio_capsfilter)?;
    audio_capsfilter.link(&rtpfunnel)?;

    debug!("linking rtpfunnel -> rtpbin");
    rtpfunnel.link_pads(None, &rtpbin, Some("send_rtp_sink_0"))?;

    debug!("link dtlssrtpdec -> rtpbin");
    dtlssrtpdec.link_pads(Some("rtp_src"), &rtpbin, Some("recv_rtp_sink_0"))?;
    dtlssrtpdec.link_pads(Some("rtcp_src"), &rtpbin, Some("recv_rtcp_sink_0"))?;

    debug!("linking rtpbin -> dtlssrtpenc");
    rtpbin.link_pads(Some("send_rtp_src_0"), &dtlssrtpenc, Some("rtp_sink_0"))?;
    rtpbin.link_pads(Some("send_rtcp_src_0"), &dtlssrtpenc, Some("rtcp_sink_0"))?;

    debug!("linking ice src -> dtlssrtpdec");
    nicesrc.link(&dtlssrtpdec)?;

    debug!("linking dtlssrtpenc -> ice sink");
    dtlssrtpenc.link_pads(Some("src"), &nicesink, Some("sink"))?;

    let bus = pipeline.bus().context("failed to get pipeline bus")?;

    let (pipeline_state_null_tx, pipeline_state_null_rx) = oneshot::channel();
    tokio::spawn(async move {
      let mut stream = bus.stream();
      while let Some(msg) = stream.next().await {
        match msg.view() {
          gstreamer::MessageView::Error(e) => {
            if let Some(d) = e.debug() {
              error!("{}", d);
            }
          },
          gstreamer::MessageView::Warning(e) => {
            if let Some(d) = e.debug() {
              warn!("{}", d);
            }
          },
          gstreamer::MessageView::StateChanged(state)
            if state.current() == gstreamer::State::Null =>
          {
            debug!("pipeline state is null");
            pipeline_state_null_tx.send(()).unwrap();
            break;
          }
          _ => {},
        }
      }
    });

    gstreamer::debug_bin_to_dot_file(
      &pipeline,
      gstreamer::DebugGraphDetails::ALL,
      "session-initiate",
    );

    let local_candidates = ice_agent.local_candidates(ice_stream_id, ice_component_id);
    debug!("local candidates: {:?}", local_candidates);

    debug!("building Jingle session-accept");
    let mut jingle_accept = Jingle::new(Action::SessionAccept, jingle.sid.clone())
      .with_initiator(
        jingle
          .initiator
          .as_ref()
          .context("jingle session-initiate with no initiator")?
          .clone(),
      )
      .with_responder(Jid::Full(conference.jid.clone()));

    for initiate_content in &jingle.contents {
      let mut description = RtpDescription::new(initiate_content.name.0.clone());

      description.payload_types = if initiate_content.name.0 == "audio" {
        let mut pt = PayloadType::new(
          opus_payload_type.context("no opus payload type in jingle session-initiate")?,
          "opus".to_owned(),
          48000,
          2,
        );
        pt.rtcp_fbs = opus_rtcp_fbs.clone().unwrap_or_default();
        vec![pt]
      }
      else {
        let mut pts = vec![];
        match conference.config.video_codec.as_str() {
          "h264" => {
            if let Some(h264_pt) = h264_payload_type {
              let mut pt = PayloadType::new(h264_pt, "H264".to_owned(), 90000, 1);
              pt.rtcp_fbs = h264_rtcp_fbs.clone().unwrap_or_default();
              pts.push(pt);
              if let Some(rtx_pt) = h264_rtx_payload_type {
                let mut rtx_pt = PayloadType::new(rtx_pt, "rtx".to_owned(), 90000, 1);
                rtx_pt.parameters = vec![jingle_rtp::Parameter {
                  name: "apt".to_owned(),
                  value: h264_pt.to_string(),
                }];
                pts.push(rtx_pt);
              }
            }
            else {
              bail!("no h264 payload type in jingle session-initiate");
            }
          },
          "vp8" => {
            if let Some(vp8_pt) = vp8_payload_type {
              let mut pt = PayloadType::new(vp8_pt, "VP8".to_owned(), 90000, 1);
              pt.rtcp_fbs = vp8_rtcp_fbs.clone().unwrap_or_default();
              pts.push(pt);
              if let Some(rtx_pt) = vp8_rtx_payload_type {
                let mut rtx_pt = PayloadType::new(rtx_pt, "rtx".to_owned(), 90000, 1);
                rtx_pt.parameters = vec![jingle_rtp::Parameter {
                  name: "apt".to_owned(),
                  value: vp8_pt.to_string(),
                }];
                pts.push(rtx_pt);
              }
            }
            else {
              bail!("no vp8 payload type in jingle session-initiate");
            }
          },
          "vp9" => {
            if let Some(vp9_pt) = vp9_payload_type {
              let mut pt = PayloadType::new(vp9_pt, "VP9".to_owned(), 90000, 1);
              pt.rtcp_fbs = vp9_rtcp_fbs.clone().unwrap_or_default();
              pts.push(pt);
              if let Some(rtx_pt) = vp9_rtx_payload_type {
                let mut rtx_pt = PayloadType::new(rtx_pt, "rtx".to_owned(), 90000, 1);
                rtx_pt.parameters = vec![jingle_rtp::Parameter {
                  name: "apt".to_owned(),
                  value: vp9_pt.to_string(),
                }];
                pts.push(rtx_pt);
              }
            }
            else {
              bail!("no vp9 payload type in jingle session-initiate");
            }
          },
          other => bail!("unsupported video codec: {}", other),
        }
        pts
      };

      description.rtcp_mux = Some(RtcpMux);

      let mslabel = Uuid::new_v4().to_string();
      let label = Uuid::new_v4().to_string();
      let cname = Uuid::new_v4().to_string();

      description.ssrc = Some(if initiate_content.name.0 == "audio" {
        audio_ssrc.to_string()
      }
      else {
        video_ssrc.to_string()
      });

      description.ssrcs = if initiate_content.name.0 == "audio" {
        vec![jingle_ssma::Source::new(audio_ssrc.to_string())]
      }
      else {
        vec![
          jingle_ssma::Source::new(video_ssrc.to_string()),
          jingle_ssma::Source::new(video_rtx_ssrc.to_string()),
        ]
      };

      for ssrc in description.ssrcs.iter_mut() {
        ssrc.parameters.push(Parameter {
          name: "cname".to_owned(),
          value: Some(cname.clone()),
        });
        ssrc.parameters.push(Parameter {
          name: "msid".to_owned(),
          value: Some(format!("{} {}", mslabel, label)),
        });
      }

      description.ssrc_groups = if initiate_content.name.0 == "audio" {
        vec![]
      }
      else {
        vec![jingle_ssma::Group {
          semantics: "FID".to_owned(),
          sources: vec![
            jingle_ssma::Source::new(video_ssrc.to_string()),
            jingle_ssma::Source::new(video_rtx_ssrc.to_string()),
          ],
        }]
      };

      if initiate_content.name.0 == "audio" {
        if let Some(hdrext) = audio_hdrext_ssrc_audio_level {
          description.hdrexts.push(RtpHdrext::new(
            hdrext.to_string(),
            RTP_HDREXT_SSRC_AUDIO_LEVEL.to_owned(),
          ));
        }
        if let Some(hdrext) = audio_hdrext_transport_cc {
          description.hdrexts.push(RtpHdrext::new(
            hdrext.to_string(),
            RTP_HDREXT_TRANSPORT_CC.to_owned(),
          ));
        }
      }
      else if initiate_content.name.0 == "video" {
        // if let Some(hdrext) = video_hdrext_abs_send_time {
        //   description.hdrexts.push(RtpHdrext::new(hdrext.to_string(), RTP_HDREXT_ABS_SEND_TIME.to_owned()));
        // }
        if let Some(hdrext) = video_hdrext_transport_cc {
          description.hdrexts.push(RtpHdrext::new(
            hdrext.to_string(),
            RTP_HDREXT_TRANSPORT_CC.to_owned(),
          ));
        }
      }

      let mut transport = IceUdpTransport::new().with_fingerprint(Fingerprint {
        hash: Algo::Sha_256,
        setup: Some(Setup::Active),
        value: fingerprint.clone(),
        required: Some(true.to_string()),
      });
      transport.ufrag = Some(ice_local_ufrag.clone());
      transport.pwd = Some(ice_local_pwd.clone());
      transport.candidates = vec![];
      for c in &local_candidates {
        let addr = c.addr();
        let foundation = c.foundation()?;
        transport.candidates.push(jingle_ice_udp::Candidate {
          component: c.component_id() as u8,
          foundation: foundation.to_owned(),
          generation: 0,
          id: Uuid::new_v4().to_string(),
          ip: addr.ip(),
          port: addr.port(),
          priority: c.priority(),
          protocol: "udp".to_owned(),
          type_: match c.type_() {
            nice::CandidateType::Host => jingle_ice_udp::Type::Host,
            nice::CandidateType::PeerReflexive => jingle_ice_udp::Type::Prflx,
            nice::CandidateType::ServerReflexive => jingle_ice_udp::Type::Srflx,
            nice::CandidateType::Relayed => jingle_ice_udp::Type::Relay,
            other => bail!("unsupported candidate type: {:?}", other),
          },
          rel_addr: None,
          rel_port: None,
          network: None,
        });
      }

      jingle_accept = jingle_accept.add_content(
        Content::new(Creator::Responder, initiate_content.name.clone())
          .with_senders(Senders::Both)
          .with_description(description)
          .with_transport(transport),
      );
    }

    let accept_iq_id = generate_id();
    let session_accept_iq = Iq::from_set(accept_iq_id.clone(), jingle_accept)
      .with_to(Jid::Full(conference.focus_jid_in_muc()?))
      .with_from(Jid::Full(conference.jid.clone()));
    conference.xmpp_tx.send(session_accept_iq.into()).await?;

    Ok(Self {
      pipeline,
      audio_sink_element,
      video_sink_element,
      remote_ssrc_map,
      _ice_agent: ice_agent,
      accept_iq_id: Some(accept_iq_id),
      colibri_url,
      colibri_channel: None,
      pipeline_state_null_rx,
    })
  }

  pub(crate) async fn source_add(&mut self, jingle: Jingle) -> Result<()> {
    for content in &jingle.contents {
      if let Some(Description::Rtp(description)) = &content.description {
        for ssrc in &description.ssrcs {
          let owner = ssrc
            .info
            .as_ref()
            .context("missing ssrc-info")?
            .owner
            .clone();

          debug!("adding ssrc to remote_ssrc_map: {:?}", ssrc);
          self.remote_ssrc_map.insert(
            ssrc.id.parse()?,
            Source {
              ssrc: ssrc.id.parse()?,
              participant_id: if owner == "jvb" {
                None
              }
              else {
                Some(
                  owner
                    .split('/')
                    .nth(1)
                    .context("invalid ssrc-info owner")?
                    .to_owned(),
                )
              },
              media_type: if description.media == "audio" {
                MediaType::Audio
              }
              else {
                MediaType::Video
              },
            },
          );
        }
      }
    }
    Ok(())
  }
}