Share a buffer between Sodium and Opus

src/Discord.Net/Audio/Opus/OpusEncoder.cs

@@ -28,7 +28,6 @@ namespace Discord.Audio
                 throw new Exception($"Opus Error: {error}");
         }
 
-
         /// <summary> Produces Opus encoded audio from PCM samples. </summary>
         /// <param name="input">PCM samples to encode.</param>
         /// <param name="output">Buffer to store the encoded frame.</param>

src/Discord.Net/Audio/Streams/OpusEncodeStream.cs

@@ -4,15 +4,13 @@
     {
         public int SampleRate = 48000;
         public int Channels = 2;
-
-        private readonly byte[] _buffer;
+        
         private readonly OpusEncoder _encoder;
 
         internal OpusEncodeStream(AudioClient audioClient, byte[] secretKey, int samplesPerFrame, uint ssrc, int? bitrate = null, 
             OpusApplication application = OpusApplication.MusicOrMixed, int bufferSize = 4000)
-            : base(audioClient, secretKey, samplesPerFrame, ssrc)
+            : base(audioClient, secretKey, samplesPerFrame, ssrc, bufferSize)
         {
-            _buffer = new byte[bufferSize];
             _encoder = new OpusEncoder(SampleRate, Channels);
 
             _encoder.SetForwardErrorCorrection(true);

src/Discord.Net/Audio/Streams/RTPWriteStream.cs

@@ -6,47 +6,48 @@ namespace Discord.Audio
     public class RTPWriteStream : Stream
     {
         private readonly AudioClient _audioClient;
-        private readonly byte[] _buffer, _nonce, _secretKey;
+        private readonly byte[] _nonce, _secretKey;
         private int _samplesPerFrame;
         private uint _ssrc, _timestamp = 0;
 
+        protected readonly byte[] _buffer;
+
         public override bool CanRead => false;
         public override bool CanSeek => false;
         public override bool CanWrite => true;
 
-
         internal RTPWriteStream(AudioClient audioClient, byte[] secretKey, int samplesPerFrame, uint ssrc, int bufferSize = 4000)
         {
             _audioClient = audioClient;
             _secretKey = secretKey;
             _samplesPerFrame = samplesPerFrame;
             _ssrc = ssrc;
-            _nonce = new byte[24];
             _buffer = new byte[bufferSize];
-            _buffer[0] = 0x80;
-            _buffer[1] = 0x78;
-            _buffer[8] = (byte)(_ssrc >> 24);
-            _buffer[9] = (byte)(_ssrc >> 16);
-            _buffer[10] = (byte)(_ssrc >> 8);
-            _buffer[11] = (byte)(_ssrc >> 0);
+            _nonce = new byte[24];
+            _nonce[0] = 0x80;
+            _nonce[1] = 0x78;
+            _nonce[8] = (byte)(_ssrc >> 24);
+            _nonce[9] = (byte)(_ssrc >> 16);
+            _nonce[10] = (byte)(_ssrc >> 8);
+            _nonce[11] = (byte)(_ssrc >> 0);
         }
 
         public override void Write(byte[] buffer, int offset, int count)
         {
             unchecked
             {
-                if (_buffer[3]++ == byte.MaxValue)
-                    _buffer[2]++;
+                if (_nonce[3]++ == byte.MaxValue)
+                    _nonce[2]++;
 
                 _timestamp += (uint)_samplesPerFrame;
-                _buffer[4] = (byte)(_timestamp >> 24);
-                _buffer[5] = (byte)(_timestamp >> 16);
-                _buffer[6] = (byte)(_timestamp >> 8);
-                _buffer[7] = (byte)(_timestamp >> 0);
+                _nonce[4] = (byte)(_timestamp >> 24);
+                _nonce[5] = (byte)(_timestamp >> 16);
+                _nonce[6] = (byte)(_timestamp >> 8);
+                _nonce[7] = (byte)(_timestamp >> 0);
             }
 
-            Buffer.BlockCopy(_buffer, 0, _nonce, 0, 12); //Copy the 12-byte header to be used for nonce
             count = SecretBox.Encrypt(buffer, offset, count, _buffer, 12, _nonce, _secretKey);
+            Buffer.BlockCopy(_nonce, 0, _buffer, 0, 12); //Copy the RTP header from nonce to buffer
             _audioClient.Send(_buffer, count + 12);
         }