internal bool PreparePacket(ReadOnlySpan <byte> pcm, out byte[] target, out int length)
{
target = null;
length = 0;
if (this.IsDisposed)
{
return(false);
}
var audioFormat = this.AudioFormat;
var packetArray = ArrayPool <byte> .Shared.Rent(this.Rtp.CalculatePacketSize(audioFormat.SampleCountToSampleSize(audioFormat.CalculateMaximumFrameSize()), this.SelectedEncryptionMode));
var packet = packetArray.AsSpan();
this.Rtp.EncodeHeader(this.Sequence, this.Timestamp, this.SSRC, packet);
var opus = packet.Slice(Rtp.HeaderSize, pcm.Length);
this.Opus.Encode(pcm, ref opus);
this.Sequence++;
this.Timestamp += (uint)audioFormat.CalculateFrameSize(audioFormat.CalculateSampleDuration(pcm.Length));
Span <byte> nonce = stackalloc byte[Sodium.NonceSize];
switch (this.SelectedEncryptionMode)
{
case EncryptionMode.XSalsa20_Poly1305:
this.Sodium.GenerateNonce(packet.Slice(0, Rtp.HeaderSize), nonce);
break;
case EncryptionMode.XSalsa20_Poly1305_Suffix:
this.Sodium.GenerateNonce(nonce);
break;
case EncryptionMode.XSalsa20_Poly1305_Lite:
this.Sodium.GenerateNonce(this.Nonce++, nonce);
break;
default:
ArrayPool <byte> .Shared.Return(packetArray);
throw new Exception("Unsupported encryption mode.");
}
Span <byte> encrypted = stackalloc byte[Sodium.CalculateTargetSize(opus)];
this.Sodium.Encrypt(opus, encrypted, nonce);
encrypted.CopyTo(packet.Slice(Rtp.HeaderSize));
packet = packet.Slice(0, this.Rtp.CalculatePacketSize(encrypted.Length, this.SelectedEncryptionMode));
this.Sodium.AppendNonce(nonce, packet, this.SelectedEncryptionMode);
target = packetArray;
length = packet.Length;
return(true);
}
internal void PreparePacket(ReadOnlySpan <byte> pcm, ref Memory <byte> target)
{
var audioFormat = AudioFormat;
var packetArray = ArrayPool <byte> .Shared.Rent(Rtp.CalculatePacketSize(audioFormat.SampleCountToSampleSize(audioFormat.CalculateMaximumFrameSize()), SelectedEncryptionMode));
var packet = packetArray.AsSpan();
Rtp.EncodeHeader(Sequence, Timestamp, SSRC, packet);
var opus = packet.Slice(Rtp.HeaderSize, pcm.Length);
Opus.Encode(pcm, ref opus);
Sequence++;
Timestamp += (uint)audioFormat.CalculateFrameSize(audioFormat.CalculateSampleDuration(pcm.Length));
Span <byte> nonce = new byte[Sodium.NonceSize];
switch (SelectedEncryptionMode)
{
case EncryptionMode.XSalsa20_Poly1305:
Sodium.GenerateNonce(packet.Slice(0, Rtp.HeaderSize), nonce);
break;
case EncryptionMode.XSalsa20_Poly1305_Suffix:
Sodium.GenerateNonce(nonce);
break;
case EncryptionMode.XSalsa20_Poly1305_Lite:
Sodium.GenerateNonce(Nonce++, nonce);
break;
default:
ArrayPool <byte> .Shared.Return(packetArray);
throw new Exception("Unsupported encryption mode.");
}
Span <byte> encrypted = new byte[Sodium.CalculateTargetSize(opus)];
Sodium.Encrypt(opus, encrypted, nonce);
encrypted.CopyTo(packet.Slice(Rtp.HeaderSize));
packet = packet.Slice(0, Rtp.CalculatePacketSize(encrypted.Length, SelectedEncryptionMode));
Sodium.AppendNonce(nonce, packet, SelectedEncryptionMode);
target = target.Slice(0, packet.Length);
packet.CopyTo(target.Span);
ArrayPool <byte> .Shared.Return(packetArray);
}
