test(ambiance): verify white disc playback cadence

ambiance/build.gradle

@@ -361,7 +361,9 @@ tasks.register("verifyAmbiance") {
 			|| !whiteDiscAudioPlayer.contains('handle.execute(channel -> channel.stop())')
 			|| whiteDiscAudioPlayer.contains('.release()')
 			|| !whiteDiscPlaybackSmoke.contains('https://www.youtube.com/watch?v=Ue5ZBe-GzSM')
-			|| !whiteDiscPlaybackSmoke.contains('Decoded audible PCM data')
+			|| !whiteDiscPlaybackSmoke.contains('PCM cadence: 100%% speed')
+			|| !whiteDiscPlaybackSmoke.contains('stream.decodedTimelineMillis() != 4_000L')
+			|| !whiteDiscPlaybackSmoke.contains('stream.paddedSilenceBytes() != 0L')
 			|| !javaText.contains('SoundSource.RECORDS')
 			|| !javaText.contains('channel.linearAttenuation(ATTENUATION_DISTANCE)')
 			|| !javaText.contains('LONG_HOSTS = Set.of(')

ambiance/src/main/java/fr/koka99cab/sanctuary26/ambiance/client/audio/LavaplayerAudioStream.java

@@ -19,6 +19,11 @@ final class LavaplayerAudioStream implements AudioStream {
 	private final AudioPlayer player;
 	private byte[] pending = new byte[0];
 	private int pendingOffset;
+	private long decodedBytes;
+	private long paddedSilenceBytes;
+	private long firstFrameTimecode = -1L;
+	private long lastFrameTimecode = -1L;
+	private int decodedFrames;
 	private boolean initialWaitAttempted;
 	private volatile boolean closed;
 	private volatile boolean ended;
@@ -41,18 +46,25 @@ final class LavaplayerAudioStream implements AudioStream {
 				int length = Math.min(output.remaining(), pending.length - pendingOffset);
 				output.put(pending, pendingOffset, length);
 				pendingOffset += length;
+				decodedBytes += length;
 				continue;
 			}
 			AudioFrame frame = nextFrame();
 			if (frame == null) {
 				if (ended) break;
-				while (output.hasRemaining()) output.put((byte) 0);
+				while (output.hasRemaining()) {
+					output.put((byte) 0);
+					paddedSilenceBytes++;
+				}
 				break;
 			}
 			if (frame.isTerminator()) {
 				ended = true;
 				break;
 			}
+			if (firstFrameTimecode < 0L) firstFrameTimecode = frame.getTimecode();
+			lastFrameTimecode = frame.getTimecode();
+			decodedFrames++;
 			pending = frame.getData();
 			pendingOffset = 0;
 		}
@@ -86,6 +98,19 @@ final class LavaplayerAudioStream implements AudioStream {
 		return player == expectedPlayer;
 	}
 
+	long decodedBytes() {
+		return decodedBytes;
+	}
+
+	long paddedSilenceBytes() {
+		return paddedSilenceBytes;
+	}
+
+	long decodedTimelineMillis() {
+		if (decodedFrames == 0) return 0L;
+		return lastFrameTimecode - firstFrameTimecode + 20L;
+	}
+
 	@Override
 	public void close() {
 		if (closed) return;

ambiance/src/test/java/fr/koka99cab/sanctuary26/ambiance/client/audio/WhiteDiscPlaybackSmoke.java

@@ -30,29 +30,45 @@ public final class WhiteDiscPlaybackSmoke {
 			AudioPlayer player = manager.createPlayer();
 			player.playTrack(track);
 			LavaplayerAudioStream stream = new LavaplayerAudioStream(player);
-			int decodedBytes = 0;
 			int totalBytes = 0;
+			long squaredSampleSum = 0L;
+			int sampleCount = 0;
+			int peakSample = 0;
 			for (int index = 0; index < 4; index++) {
 				ByteBuffer pcm = stream.read(LavaplayerAudioStream.SAMPLE_RATE * 2);
 				if (pcm == null) break;
-				while (pcm.hasRemaining()) {
-					totalBytes++;
-					if (pcm.get() != 0) decodedBytes++;
+				totalBytes += pcm.remaining();
+				while (pcm.remaining() >= 2) {
+					int low = Byte.toUnsignedInt(pcm.get());
+					int high = pcm.get();
+					short sample = (short) ((high << 8) | low);
+					int magnitude = Math.abs((int) sample);
+					peakSample = Math.max(peakSample, magnitude);
+					squaredSampleSum += (long) sample * sample;
+					sampleCount++;
 				}
 			}
-			if (decodedBytes == 0) {
-				throw new IllegalStateException("YouTube playback produced no audible PCM data");
-			}
-			double audibleRatio = (double) decodedBytes / totalBytes;
-			if (totalBytes != LavaplayerAudioStream.SAMPLE_RATE * 2 * 4) {
+			int expectedBytes = LavaplayerAudioStream.SAMPLE_RATE * 2 * 4;
+			if (totalBytes != expectedBytes) {
 				throw new IllegalStateException("YouTube playback did not fill four PCM seconds");
 			}
-			if (audibleRatio < 0.75) {
-				throw new IllegalStateException("YouTube PCM stream was mostly silence: "
-					+ Math.round(audibleRatio * 100.0) + "% audible bytes");
+			if (stream.decodedBytes() != expectedBytes || stream.paddedSilenceBytes() != 0L) {
+				throw new IllegalStateException("YouTube playback was not 100% decoded PCM: "
+					+ stream.decodedBytes() + " decoded bytes and "
+					+ stream.paddedSilenceBytes() + " padded bytes");
 			}
-			System.out.printf("Decoded audible PCM data: %.1f%% at %.0f Hz from %s%n",
-				audibleRatio * 100.0, stream.getFormat().getSampleRate(), track.getInfo().title);
+			if (stream.decodedTimelineMillis() != 4_000L) {
+				throw new IllegalStateException("PCM cadence mismatch: four seconds of samples cover "
+					+ stream.decodedTimelineMillis() + " ms of the YouTube timeline");
+			}
+			double rmsSample = Math.sqrt((double) squaredSampleSum / sampleCount);
+			if (rmsSample < 256.0 || peakSample < 2_048) {
+				throw new IllegalStateException("YouTube PCM signal is too quiet: RMS "
+					+ Math.round(rmsSample) + ", peak " + peakSample);
+			}
+			System.out.printf(
+				"PCM cadence: 100%% speed, 4000 ms decoded into 4000 ms at %.0f Hz; RMS %.0f, peak %d from %s%n",
+				stream.getFormat().getSampleRate(), rmsSample, peakSample, track.getInfo().title);
 			stream.close();
 		} finally {
 			manager.shutdown();