Give back a speaker's line after 30 s of silence

Every client that ever spoke kept an open playback line and a thread
until it left the server. A speaker silent for 30 s now has both
released, and its next talk burst opens them again.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ts3-client/core/src/main/java/com/ts3client/audio/PerSpeakerPlayout.java

@@ -20,6 +20,8 @@ final class PerSpeakerPlayout implements Playout {
 
     private static final long FRAME_NANOS =
             TimeUnit.SECONDS.toNanos(VoiceFormat.FRAME_SIZE) / VoiceFormat.SAMPLE_RATE;
+    /** Silence after which a speaker's line and thread are given back; the next burst reopens them. */
+    private static final long IDLE_RELEASE_NANOS = TimeUnit.SECONDS.toNanos(30);
 
     private final class Speaker {
         final VoiceStream stream;
@@ -32,6 +34,8 @@ final class PerSpeakerPlayout implements Playout {
         final byte[] out;
         /** Guarded by this speaker. */
         ScheduledFuture<?> ticks;
+        /** Guarded by this speaker; a closed speaker is never ticked again. */
+        boolean closed;
 
         Speaker(VoiceStream stream) throws Exception {
             this.stream = stream;
@@ -49,6 +53,7 @@ final class PerSpeakerPlayout implements Playout {
 
         void close() {
             synchronized (this) {
+                closed = true;
                 if (ticks != null) ticks.cancel(false);
             }
             worker.shutdownNow();
@@ -68,10 +73,12 @@ final class PerSpeakerPlayout implements Playout {
         this.outputDevice = outputDevice;
         this.gain = gain;
         this.clock = clock;
+        clock.scheduleWithFixedDelay(this::releaseIdle, 1, 1, TimeUnit.SECONDS);
     }
 
     @Override
     public void started(VoiceStream stream) {
+        while (true) {
             Speaker speaker = speakers.get(stream);
             if (speaker == null) {
                 try {
@@ -87,11 +94,31 @@ final class PerSpeakerPlayout implements Playout {
                 }
             }
             synchronized (speaker) {
+                if (speaker.closed) {
+                    // Released a moment ago; this burst gets a fresh line.
+                    speakers.remove(stream, speaker);
+                    continue;
+                }
                 if (speaker.ticks == null) {
                     Speaker s = speaker;
                     speaker.ticks = clock.scheduleAtFixedRate(
                             () -> queueTick(s), FRAME_NANOS, FRAME_NANOS, TimeUnit.NANOSECONDS);
                 }
+                return;
+            }
+        }
+    }
+
+    /** Gives back the line and thread of every speaker that has been silent for a while. */
+    private void releaseIdle() {
+        long now = System.nanoTime();
+        for (Speaker speaker : speakers.values()) {
+            synchronized (speaker) {
+                if (speaker.ticks != null || now - speaker.stream.lastPacketNanos() < IDLE_RELEASE_NANOS) continue;
+                speaker.closed = true;
+            }
+            speakers.remove(speaker.stream, speaker);
+            speaker.close();
         }
     }