Merge pull request #154 from Devoxin/feature/equalizer

Equalizer stuff

Author: freyacodes

IMPLEMENTATION.md

@@ -110,6 +110,24 @@ Set player volume. Volume may range from 0 to 1000. 100 is default.
 }
 ```
 
+Using the player equalizer
+```json
+{
+    "op": "equalizer",
+    "guildId": "...",
+    "bands": [
+        {
+            "band": 0,
+            "gain": 0.2
+        }
+    ]
+}
+```
+There are 16 bands (0-15) that can be changed.
+`gain` is the multiplier for the given band. The default value is 0. Valid values range from -0.25 to 1.0,
+where -0.25 means the given band is completely muted, and 0.25 means it is doubled. Modifying the gain could
+also change the volume of the output.
+
 Tell the server to potentially disconnect from the voice server and potentially remove the player with all its data.
 This is useful if you want to move to a new node for a voice connection. Calling this op does not affect voice state,
 and you can send the same VOICE_SERVER_UPDATE to a new node.

LavalinkServer/src/main/java/lavalink/server/io/SocketServer.kt

@@ -105,6 +105,7 @@ class SocketServer(private val serverConfig: ServerConfig, private val audioPlay
             "pause"       -> handlers.pause(session, json)
             "seek"        -> handlers.seek(session, json)
             "volume"      -> handlers.volume(session, json)
+            "equalizer"   -> handlers.equalizer(session, json)
             "destroy"     -> handlers.destroy(session, json)
             else          -> log.warn("Unexpected operation: " + json.getString("op"))
         }

LavalinkServer/src/main/java/lavalink/server/io/WebSocketHandlers.kt

@@ -88,6 +88,16 @@ class WebSocketHandlers(private val contextMap: Map<String, SocketContext>) {
         player.setVolume(json.getInt("volume"))
     }
 
+    fun equalizer(session: WebSocketSession, json: JSONObject) {
+        val player = contextMap[session.id]!!.getPlayer(json.getString("guildId"))
+        val bands = json.getJSONArray("bands")
+
+        for (i in 0 until bands.length()) {
+            val band = bands.getJSONObject(i)
+            player.setBandGain(band.getInt("band"), band.getFloat("gain"))
+        }
+    }
+
     fun destroy(session: WebSocketSession, json: JSONObject) {
         val socketContext = contextMap[session.id]!!
         val player = socketContext.players.remove(json.getString("guildId"))

LavalinkServer/src/main/java/lavalink/server/player/Player.java

@@ -22,6 +22,8 @@
 
 package lavalink.server.player;
 
+import com.sedmelluq.discord.lavaplayer.filter.equalizer.Equalizer;
+import com.sedmelluq.discord.lavaplayer.filter.equalizer.EqualizerFactory;
 import com.sedmelluq.discord.lavaplayer.player.AudioPlayer;
 import com.sedmelluq.discord.lavaplayer.player.AudioPlayerManager;
 import com.sedmelluq.discord.lavaplayer.player.event.AudioEventAdapter;
@@ -48,6 +50,8 @@ public class Player extends AudioEventAdapter implements AudioSendHandler {
     private AudioLossCounter audioLossCounter = new AudioLossCounter();
     private AudioFrame lastFrame = null;
     private ScheduledFuture myFuture = null;
+    private EqualizerFactory equalizerFactory = new EqualizerFactory();
+    private boolean isEqualizerApplied = false;
 
     public Player(SocketContext socketContext, String guildId, AudioPlayerManager audioPlayerManager) {
         this.socketContext = socketContext;
@@ -86,6 +90,32 @@ public void setVolume(int volume) {
         player.setVolume(volume);
     }
 
+    public void setBandGain(int band, float gain) {
+        equalizerFactory.setGain(band, gain);
+
+        if (gain == 0.0f) {
+            if (!isEqualizerApplied) {
+                return;
+            }
+
+            boolean shouldDisable = true;
+
+            for (int i = 0; i < Equalizer.BAND_COUNT; i++) {
+                if (equalizerFactory.getGain(i) != 0.0f) {
+                    shouldDisable = false;
+                }
+            }
+
+            if (shouldDisable) {
+                this.player.setFilterFactory(null);
+                this.isEqualizerApplied = false;
+            }
+        } else {
+            this.player.setFilterFactory(equalizerFactory);
+            this.isEqualizerApplied = true;
+        }
+    }
+
     public JSONObject getState() {
         JSONObject json = new JSONObject();