private bool ProcessPacket(ReadOnlySpan <byte> data, ref Memory <byte> opus, ref Memory <byte> pcm, IList <ReadOnlyMemory <byte> > pcmPackets, out AudioSender voiceSender, out AudioFormat outputFormat)
{
voiceSender = null;
outputFormat = default;
if (!this.Rtp.IsRtpHeader(data))
{
return(false);
}
this.Rtp.DecodeHeader(data, out var sequence, out var timestamp, out var ssrc, out var hasExtension);
if (!this.TransmittingSSRCs.TryGetValue(ssrc, out var vtx))
{
var decoder = Opus.CreateDecoder();
vtx = new AudioSender(ssrc, decoder)
{
// user isn't present as we haven't received a speaking event yet.
User = null
};
}
voiceSender = vtx;
if (sequence <= vtx.LastSequence) // out-of-order packet; discard
{
return(false);
}
var gap = vtx.LastSequence != 0 ? sequence - 1 - vtx.LastSequence : 0;
if (gap >= 5)
{
this.Discord.Logger.LogWarning(VoiceNextEvents.VoiceReceiveFailure, "5 or more voice packets were dropped when receiving");
}
Span <byte> nonce = stackalloc byte[Sodium.NonceSize];
this.Sodium.GetNonce(data, nonce, this.SelectedEncryptionMode);
this.Rtp.GetDataFromPacket(data, out var encryptedOpus, this.SelectedEncryptionMode);
var opusSize = Sodium.CalculateSourceSize(encryptedOpus);
opus = opus.Slice(0, opusSize);
var opusSpan = opus.Span;
try
{
this.Sodium.Decrypt(encryptedOpus, opusSpan, nonce);
// Strip extensions, if any
if (hasExtension)
{
// RFC 5285, 4.2 One-Byte header
// http://www.rfcreader.com/#rfc5285_line186
if (opusSpan[0] == 0xBE && opusSpan[1] == 0xDE)
{
var headerLen = opusSpan[2] << 8 | opusSpan[3];
var i = 4;
for (; i < headerLen + 4; i++)
{
var @byte = opusSpan[i];
// ID is currently unused since we skip it anyway
//var id = (byte)(@byte >> 4);
var length = (byte)(@byte & 0x0F) + 1;
i += length;
}
// Strip extension padding too
while (opusSpan[i] == 0)
{
i++;
}
opusSpan = opusSpan.Slice(i);
}
// TODO: consider implementing RFC 5285, 4.3. Two-Byte Header
}
if (opusSpan[0] == 0x90)
{
// I'm not 100% sure what this header is/does, however removing the data causes no
// real issues, and has the added benefit of removing a lot of noise.
opusSpan = opusSpan.Slice(2);
}
if (gap == 1)
{
var lastSampleCount = this.Opus.GetLastPacketSampleCount(vtx.Decoder);
var fecpcm = new byte[this.AudioFormat.SampleCountToSampleSize(lastSampleCount)];
var fecpcmMem = fecpcm.AsSpan();
this.Opus.Decode(vtx.Decoder, opusSpan, ref fecpcmMem, true, out _);
pcmPackets.Add(fecpcm.AsMemory(0, fecpcmMem.Length));
}
else if (gap > 1)
{
var lastSampleCount = this.Opus.GetLastPacketSampleCount(vtx.Decoder);
for (var i = 0; i < gap; i++)
{
var fecpcm = new byte[this.AudioFormat.SampleCountToSampleSize(lastSampleCount)];
var fecpcmMem = fecpcm.AsSpan();
this.Opus.ProcessPacketLoss(vtx.Decoder, lastSampleCount, ref fecpcmMem);
pcmPackets.Add(fecpcm.AsMemory(0, fecpcmMem.Length));
}
}
var pcmSpan = pcm.Span;
this.Opus.Decode(vtx.Decoder, opusSpan, ref pcmSpan, false, out outputFormat);
pcm = pcm.Slice(0, pcmSpan.Length);
}
finally
{
vtx.LastSequence = sequence;
}
return(true);
}
private async Task HandleDispatch(JObject jo)
{
var opc = (int)jo["op"];
var opp = jo["d"] as JObject;
switch (opc)
{
case 2: // READY
Discord.DebugLogger.LogMessage(LogLevel.Debug, "VoiceNext", "OP2 received", DateTime.Now);
var vrp = opp.ToObject <VoiceReadyPayload>();
SSRC = vrp.SSRC;
ConnectionEndpoint = new ConnectionEndpoint(ConnectionEndpoint.Hostname, vrp.Port);
// this is not the valid interval
// oh, discord
//this.HeartbeatInterval = vrp.HeartbeatInterval;
HeartbeatTask = Task.Run(HeartbeatAsync);
await Stage1(vrp).ConfigureAwait(false);
break;
case 4: // SESSION_DESCRIPTION
Discord.DebugLogger.LogMessage(LogLevel.Debug, "VoiceNext", "OP4 received", DateTime.Now);
var vsd = opp.ToObject <VoiceSessionDescriptionPayload>();
Key = vsd.SecretKey;
Sodium = new DSharpPlus.VoiceNext.Codec.Sodium(Key.AsMemory());
await Stage2(vsd).ConfigureAwait(false);
break;
case 5: // SPEAKING
// Don't spam OP5
//this.Discord.DebugLogger.LogMessage(LogLevel.Debug, "VoiceNext", "OP5 received", DateTime.Now);
var spd = opp.ToObject <VoiceSpeakingPayload>();
var spk = new UserSpeakingEventArgs(Discord)
{
Speaking = spd.Speaking,
SSRC = spd.SSRC.Value,
};
if (spk.UserId != 0 && TransmittingSSRCs.TryGetValue(spk.SSRC, out var txssrc5) && txssrc5.UserId == 0)
{
txssrc5.UserId = spk.UserId;
}
else
{
var opus = Opus.CreateDecoder();
var vtx = new AudioSender(spk.SSRC, opus)
{
UserId = spd.UserId.Value
};
if (!TransmittingSSRCs.TryAdd(spk.SSRC, vtx))
{
Opus.DestroyDecoder(opus);
}
}
await _userSpeaking.InvokeAsync(spk).ConfigureAwait(false);
break;
case 6: // HEARTBEAT ACK
var dt = DateTime.Now;
var ping = (int)(dt - LastHeartbeat).TotalMilliseconds;
Volatile.Write(ref _wsPing, ping);
Discord.DebugLogger.LogMessage(LogLevel.Debug, "VoiceNext", $"Received voice heartbeat ACK, ping {ping.ToString("#,##0", CultureInfo.InvariantCulture)}ms", dt);
LastHeartbeat = dt;
break;
case 8: // HELLO
// this sends a heartbeat interval that we need to use for heartbeating
HeartbeatInterval = opp["heartbeat_interval"].ToObject <int>();
break;
case 9: // RESUMED
Discord.DebugLogger.LogMessage(LogLevel.Debug, "VoiceNext", "OP9 received", DateTime.Now);
HeartbeatTask = Task.Run(HeartbeatAsync);
break;
case 12: // CLIENT_CONNECTED
var ujpd = opp.ToObject <VoiceUserJoinPayload>();
{
var opus = Opus.CreateDecoder();
var vtx = new AudioSender(ujpd.SSRC, opus)
{
UserId = ujpd.UserId
};
if (!TransmittingSSRCs.TryAdd(vtx.SSRC, vtx))
{
Opus.DestroyDecoder(opus);
}
}
await _userJoined.InvokeAsync(new VoiceUserJoinEventArgs(Discord) { UserId = ujpd.UserId, SSRC = ujpd.SSRC }).ConfigureAwait(false);
break;
case 13: // CLIENT_DISCONNECTED
var ulpd = opp.ToObject <VoiceUserLeavePayload>();
var txssrc = TransmittingSSRCs.FirstOrDefault(x => x.Value.Id == ulpd.UserId);
if (TransmittingSSRCs.ContainsKey(txssrc.Key))
{
TransmittingSSRCs.TryRemove(txssrc.Key, out var txssrc13);
Opus.DestroyDecoder(txssrc13.Decoder);
}
await _userLeft.InvokeAsync(new VoiceUserLeaveEventArgs(Discord)
{
UserId = ulpd.UserId,
SSRC = txssrc.Key
}).ConfigureAwait(false);
break;
default:
Discord.DebugLogger.LogMessage(LogLevel.Warning, "VoiceNext", $"Unknown opcode received: {opc.ToString(CultureInfo.InvariantCulture)}", DateTime.Now);
break;
}
}