/// <summary>
/// Updates the session after receiving the remote SDP.
/// At this point check that the codecs match. We currently only support:
/// - Audio: PCMU,
/// - Video: VP8.
/// If they are not available there's no point carrying on.
/// </summary>
/// <param name="remoteSdp">The answer/offer SDP from the remote party.</param>
public void OnSdpAnswer(SDP remoteSdp)
{
// Check remote party audio is acceptable.
if (_supportedAudioFormats?.Count() > 0)
{
var remoteAudioOffer = remoteSdp.Media.Where(x => x.Media == SDPMediaTypesEnum.audio).FirstOrDefault();
if (remoteAudioOffer?.MediaFormats.Count() == 0)
{
logger.LogWarning("No audio formats were available in the remote party's SDP.");
Close("No audio codecs offered.");
}
else if (remoteAudioOffer.MediaFormats.Select(x => x.FormatCodec).Union(_supportedAudioFormats.Select(y => y.FormatCodec)).Count() == 0)
{
logger.LogWarning("No matching audio codec was available.");
Close("No matching audio codec.");
}
}
// Check remote party video is acceptable.
if (_supportedVideoFormats?.Count() > 0)
{
var remoteVideoOffer = remoteSdp.Media.Where(x => x.Media == SDPMediaTypesEnum.video).FirstOrDefault();
if (remoteVideoOffer?.MediaFormats.Count() == 0)
{
logger.LogWarning("No video formats were available in the remote party's SDP.");
Close("No video codecs offered.");
}
else if (remoteVideoOffer.MediaFormats.Select(x => x.FormatCodec).Union(_supportedVideoFormats.Select(y => y.FormatCodec)).Count() == 0)
{
logger.LogWarning("No matching video codec was available.");
Close("No matching video codec.");
}
// Since we only currently support VP8 there's only a single remote payload ID that can be
// associated with the video stream.
var remoteVP8MediaFormat = remoteVideoOffer.MediaFormats.Where(x => x.FormatCodec == SDPMediaFormatsEnum.VP8).Single();
RtpSession.AddStream(SDPMediaTypesEnum.video, VP8_PAYLOAD_TYPE_ID, new List <int> {
Convert.ToInt32(remoteVP8MediaFormat.FormatID)
});
}
SdpSessionID = remoteSdp.SessionId;
RemoteIceUser = remoteSdp.IceUfrag;
RemoteIcePassword = remoteSdp.IcePwd;
// All browsers seem to have gone to trickling ICE candidates now but just
// in case one or more are given we can start the STUN dance immediately.
if (remoteSdp.IceCandidates != null)
{
foreach (var iceCandidate in remoteSdp.IceCandidates)
{
AppendRemoteIceCandidate(iceCandidate);
}
}
}
public WebRtcSession(string dtlsFingerprint, List <IPAddress> offerAddresses)
{
_dtlsCertificateFingerprint = dtlsFingerprint;
SessionID = Guid.NewGuid().ToString();
_rtpSession = new RTPSession((int)SDPMediaFormatsEnum.PCMU, AddressFamily.InterNetwork, true);
_videoSessionID = _rtpSession.AddStream(VP8_PAYLOAD_TYPE_ID, null);
_rtpChannel = _rtpSession.RtpChannel;
_rtpChannel.OnRTPDataReceived += OnRTPDataReceived;
_rtpSession.OnRtpClosed += Close;
_offerAddresses = offerAddresses;
}
