Allow adjustment of opus encoding & resampling quality fields in AudioConfiguration (#699)

* Allow setting opusEncoding & resampling quality

* Mark resamplingQuality as nullable so it can be omitted

* Support useSeekGhosting setting.

Author: devoxin

LavalinkServer/application.yml.example

@@ -14,7 +14,10 @@ lavalink:
       local: false
     bufferDurationMs: 400 # The duration of the NAS buffer. Higher values fare better against longer GC pauses. Minimum of 40ms, lower values may introduce pauses.
     frameBufferDurationMs: 5000 # How many milliseconds of audio to keep buffered
-    trackStuckThresholdMs: 10000  # The threshold for how long a track can be stuck. A track is stuck if does not return any audio data.
+    opusEncodingQuality: 10 # Opus encoder quality. Valid values range from 0 to 10, where 10 is best quality but is the most expensive on the CPU.
+    resamplingQuality: LOW # Quality of resampling operations. Valid values are LOW, MEDIUM and HIGH, where HIGH uses the most CPU.
+    trackStuckThresholdMs: 10000 # The threshold for how long a track can be stuck. A track is stuck if does not return any audio data.
+    useSeekGhosting: true # Seek ghosting is the effect where whilst a seek is in progress, the audio buffer is read from until empty, or until seek is ready.
     youtubePlaylistLoadLimit: 6 # Number of pages at 100 each
     playerUpdateInterval: 5 # How frequently to send player updates to clients, in seconds
     youtubeSearchEnabled: true

LavalinkServer/src/main/java/lavalink/server/config/AudioPlayerConfiguration.kt

@@ -2,6 +2,8 @@ package lavalink.server.config
 
 import com.sedmelluq.discord.lavaplayer.container.MediaContainerProbe
 import com.sedmelluq.discord.lavaplayer.container.MediaContainerRegistry
+import com.sedmelluq.discord.lavaplayer.player.AudioConfiguration
+import com.sedmelluq.discord.lavaplayer.player.AudioConfiguration.ResamplingQuality
 import com.sedmelluq.discord.lavaplayer.player.AudioPlayerManager
 import com.sedmelluq.discord.lavaplayer.player.DefaultAudioPlayerManager
 import com.sedmelluq.discord.lavaplayer.source.AudioSourceManager
@@ -65,6 +67,24 @@ class AudioPlayerConfiguration {
             audioPlayerManager.frameBufferDuration = bufferDuration
         }
 
+        val defaultOpusEncodingQuality = AudioConfiguration.OPUS_QUALITY_MAX
+        audioPlayerManager.configuration.let {
+            serverConfig.opusEncodingQuality?.let { opusQuality ->
+                if (opusQuality !in 0..10) {
+                    log.warn("Opus encoding quality {} is not within the range of 0 to 10. Defaulting to {}", opusQuality, defaultOpusEncodingQuality)
+                }
+
+                val qualitySetting = opusQuality.takeIf { it in 0..10 } ?: defaultOpusEncodingQuality
+                log.debug("Setting opusEncodingQuality to {}", qualitySetting)
+                it.opusEncodingQuality = qualitySetting
+            }
+
+            serverConfig.resamplingQuality?.let { resamplingQuality ->
+                log.debug("Setting resamplingQuality to {}", resamplingQuality)
+                it.resamplingQuality = resamplingQuality
+            }
+        }
+
         val defaultTrackStuckThresholdMs = TimeUnit.NANOSECONDS.toMillis(audioPlayerManager.trackStuckThresholdNanos)
         serverConfig.trackStuckThresholdMs?.let {
             if (it < 100) {
@@ -76,6 +96,11 @@ class AudioPlayerConfiguration {
             audioPlayerManager.setTrackStuckThreshold(trackStuckThresholdMs)
         }
 
+        serverConfig.useSeekGhosting?.let { seekGhosting ->
+            log.debug("Setting useSeekGhosting to {}", seekGhosting)
+            audioPlayerManager.setUseSeekGhosting(seekGhosting)
+        }
+
         val mcr: MediaContainerRegistry = MediaContainerRegistry.extended(*mediaContainerProbes.toTypedArray())
 
         if (sources.isYoutube) {

LavalinkServer/src/main/java/lavalink/server/config/ServerConfig.kt

@@ -22,6 +22,7 @@
 
 package lavalink.server.config
 
+import com.sedmelluq.discord.lavaplayer.player.AudioConfiguration.ResamplingQuality
 import org.springframework.boot.context.properties.ConfigurationProperties
 import org.springframework.stereotype.Component
 
@@ -33,7 +34,10 @@ class ServerConfig {
     var sentryDsn = ""
     var bufferDurationMs: Int? = null
     var frameBufferDurationMs: Int? = null
+    var opusEncodingQuality: Int? = null
+    var resamplingQuality: ResamplingQuality? = null
     var trackStuckThresholdMs: Long? = null
+    var useSeekGhosting: Boolean? = null
     var youtubePlaylistLoadLimit: Int? = null
     var playerUpdateInterval: Int = 5
     var isGcWarnings = true