From 59094d2e1feee44d55fe0c5a3cc9622c2f637cb3 Mon Sep 17 00:00:00 2001
From: Frederik P <34724135+F0903@users.noreply.github.com>
Date: Thu, 10 Aug 2023 15:15:56 +0200
Subject: [PATCH] Added a method for sending silent audio frames on
 OpusEncodeStream (#2668)

* Implemented ClientDisconnect event for audio client.

* Added a method for sending silent frames.

* moved comment

* Added method summary.
+ removed changes to project file.

* Removed residual stuff remaining from previous edits.

* bunch of things

* Revert "bunch of things"

This reverts commit 292f23f4e1aabb26d2a3e5b9a2bdff8b5554635e.

* Update src/Discord.Net.WebSocket/Audio/Streams/OpusEncodeStream.cs

* Update src/Discord.Net.WebSocket/Audio/Streams/OpusEncodeStream.cs

* Update src/Discord.Net.WebSocket/Audio/Streams/OpusEncodeStream.cs

---------

Co-authored-by: Quin Lynch <49576606+quinchs@users.noreply.github.com>
---
 .../Audio/Streams/OpusEncodeStream.cs         | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/src/Discord.Net.WebSocket/Audio/Streams/OpusEncodeStream.cs b/src/Discord.Net.WebSocket/Audio/Streams/OpusEncodeStream.cs
index 7e30b47e..cabd8487 100644
--- a/src/Discord.Net.WebSocket/Audio/Streams/OpusEncodeStream.cs
+++ b/src/Discord.Net.WebSocket/Audio/Streams/OpusEncodeStream.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Runtime.CompilerServices;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -23,6 +24,30 @@ namespace Discord.Audio.Streams
             _buffer = new byte[OpusConverter.FrameBytes];
         }
 
+        /// <summary>
+        ///     Sends silent frames to avoid interpolation errors after breaks in data transmission.
+        /// </summary>
+        /// <returns>A task representing the asynchronous operation of sending a silent frame.</returns>
+        public async Task WriteSilentFramesAsync()
+        {
+            // https://discord.com/developers/docs/topics/voice-connections#voice-data-interpolation
+
+            byte[] frameBytes = new byte[OpusConverter.FrameBytes];
+
+            // Magic silence numbers.
+            frameBytes[0] = 0xF8;
+            frameBytes[1] = 0xFF;
+            frameBytes[2] = 0xFE;
+
+            // The rest of the array is already zeroes, so no need to fill the rest.
+
+            const int frameCount = 5;
+            for (int i = 0; i < frameCount; i += 1)
+            {
+                await WriteAsync(frameBytes, 0, frameBytes.Length).ConfigureAwait(false);
+            } 
+        }
+
         public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancelToken)
         {
             //Assume thread-safe