Revert "Smooth realtime display frame pacing"

This reverts commit a8e9729b3a.

scripts/test_websocket_runtime.mjs

@@ -37,5 +37,5 @@ metrics.addEventListener('message', (event) => {
 await new Promise((resolve) => setTimeout(resolve, 1100));
 sockets.forEach((socket) => socket.close());
 assert.equal(invalidPayload, false, 'metrics must be ordered and contain no large visual payloads');
-assert.ok(count >= 110 && count <= 145, `expected about 120 metrics/s, received ${count}`);
+assert.ok(count >= 50 && count <= 75, `expected about 60 metrics/s, received ${count}`);
 console.log(`runtime websocket test passed (${count} metrics in 1.1 s; max frame age ${maxFrameAgeMs} ms; all three streams opened)`);

src/audio.rs

@@ -40,12 +40,8 @@ use crate::{
     model::{InputSource, MeterFrame, PhoenixRtaConfig},
 };
 
-// Keep transport sampling safely above the 60 Hz display cadence. ALSA only
-// exposes complete capture periods, so a 60 Hz target with 128-frame periods
-// alternates between roughly 16.0 and 18.7 ms at 48 kHz. A 120 Hz snapshot
-// clock guarantees at least one fresh native state per display frame without
-// changing any detector or ballistic calculation.
-const METRICS_TARGET_UPDATES_PER_SECOND: u32 = 120;
+#[cfg(target_os = "linux")]
+const METRICS_TARGET_UPDATES_PER_SECOND: u32 = 60;
 
 #[derive(Clone, Copy, Debug, Default)]
 struct TransportPeaks {
@@ -419,8 +415,7 @@ pub fn spawn_audio_capture_worker(deps: AudioWorkerDeps) {
 pub fn spawn_audio_capture_worker(deps: AudioWorkerDeps) {
     tokio::spawn(async move {
         warn!("Phoenix ALSA capture is only available on Linux; emitting placeholder frames on this host");
-        let tick_ns = 1_000_000_000u64 / u64::from(METRICS_TARGET_UPDATES_PER_SECOND);
-        let mut ticker = tokio::time::interval(Duration::from_nanos(tick_ns));
+        let mut ticker = tokio::time::interval(Duration::from_millis(16));
         deps.actual_sample_rate
             .store(deps.config.sample_rate as u64, Ordering::SeqCst);
         loop {

src/goniometer.rs

@@ -58,31 +58,6 @@ mod tests {
         }
     }
 
-    #[test]
-    fn double_rate_transport_never_leaves_a_sixty_hz_display_interval_empty() {
-        let sample_rate = 48_000u32;
-        let period = 128usize;
-        let mut clock = GoniometerClock::default();
-        let mut processed = 0usize;
-        let mut previous_emission = None;
-        let mut largest_gap = 0usize;
-
-        while processed < sample_rate as usize * 10 {
-            processed += period;
-            if clock.advance(period, sample_rate, 120) {
-                if let Some(previous) = previous_emission {
-                    largest_gap = largest_gap.max(processed - previous);
-                }
-                previous_emission = Some(processed);
-            }
-        }
-
-        assert!(
-            largest_gap <= sample_rate as usize / 60,
-            "largest transport gap was {largest_gap} samples"
-        );
-    }
-
     #[test]
     fn selection_never_upsamples_and_keeps_endpoints() {
         assert_eq!(selected_sample_indices(3, 1024), vec![0, 1, 2]);

www/core/audio.js

@@ -26,6 +26,7 @@ let lifecycleHandlersBound = false;
 let recoverTimer = null;
 let lastHardRecoverAt = 0;
 let pendingPhoenixFrame = null;
+let phoenixPacketRaf = 0;
 let phoenixPacketBusy = false;
 
 const RMS_RING = { L: new Float32Array(512), R: new Float32Array(512), i: 0, n: 0 };
@@ -124,6 +125,8 @@ function closePhoenixSocket() {
   if (phoenixVisualsRaf) cancelAnimationFrame(phoenixVisualsRaf);
   phoenixVisualsRaf = 0;
   pendingPhoenixFrame = null;
+  if (phoenixPacketRaf) cancelAnimationFrame(phoenixPacketRaf);
+  phoenixPacketRaf = 0;
   phoenixPacketBusy = false;
 }
 
@@ -429,6 +432,7 @@ async function applyIncomingAudioPacket(env, packet, CONFIG, sampleTs = performa
   const previousSeq = Number(env.audio.phoenixMetricsSeq || 0);
   if (Number.isFinite(seq) && seq > 0 && previousSeq > 0 && seq <= previousSeq) return;
   if (Number.isFinite(seq) && seq > 0) env.audio.phoenixMetricsSeq = seq;
+  env.requestRender?.('audio');
   env.audio.lastSampleTs = sampleTs;
   env.audio.alive = true;
   if (Number.isFinite(Number(d.sampleRate)) && Number(d.sampleRate) > 0) {
@@ -483,10 +487,6 @@ async function applyIncomingAudioPacket(env, packet, CONFIG, sampleTs = performa
   }
 
   await updateActiveMeters(env, d, CONFIG);
-  // Publish the frame only after every active meter has consumed the packet.
-  // Otherwise the canvas loop can draw between the data update and the meter
-  // update, producing an old frame followed by a visible catch-up step.
-  env.requestRender?.('audio');
 }
 
 function buildPhoenixMeterPacket(frame) {
@@ -627,26 +627,23 @@ function mergePendingPhoenixFrame(previous, next) {
 }
 
 function schedulePhoenixPacketPump(env, CONFIG) {
-  if (phoenixPacketBusy || !pendingPhoenixFrame) return;
-  phoenixPacketBusy = true;
-  void (async () => {
+  if (phoenixPacketRaf || phoenixPacketBusy || !pendingPhoenixFrame) return;
+  phoenixPacketRaf = requestAnimationFrame(async () => {
+    phoenixPacketRaf = 0;
+    const frame = pendingPhoenixFrame;
+    pendingPhoenixFrame = null;
+    if (!frame) return;
+    phoenixPacketBusy = true;
     try {
-      // Consume the newest packet immediately. Incoming packets are still
-      // coalesced while an asynchronous meter/config update is in progress,
-      // but they no longer wait for a second requestAnimationFrame loop.
-      while (pendingPhoenixFrame) {
-        const frame = pendingPhoenixFrame;
-        pendingPhoenixFrame = null;
-        const packet = buildPhoenixMeterPacket(frame);
-        await applyIncomingAudioPacket(env, packet, CONFIG, performance.now());
-      }
+      const packet = buildPhoenixMeterPacket(frame);
+      await applyIncomingAudioPacket(env, packet, CONFIG, performance.now());
     } catch (err) {
       console.warn('Phoenix packet error:', err);
     } finally {
       phoenixPacketBusy = false;
       if (pendingPhoenixFrame) schedulePhoenixPacketPump(env, CONFIG);
     }
-  })();
+  });
 }
 
 function enqueuePhoenixFrame(env, CONFIG, frame) {

www/main.js

@@ -2698,20 +2698,14 @@ async function loop(now){
   const currentAudioSeq = Math.max(currentMetricsSeq, currentVisualsSeq, currentXySeq);
   const audioDirty = currentAudioSeq > lastRenderedAudioSeq;
   const shouldRenderFrame =
-    audioOk ||
     renderDirty ||
     audioDirty ||
     !audioOk ||
     style === 'options-panel' ||
     style === 'recorder' ||
     renderStyle === 'clock';
-  // With live audio, requestAnimationFrame itself is the display clock. An
-  // additional exact 60 Hz comparison occasionally rejected a real 60 Hz
-  // frame because of fractional timestamp jitter, creating 33 ms pauses in
-  // otherwise smooth peak decay. Only throttle the disconnected state.
-  const frameDue = audioOk || elapsed >= target;
-  if (frameDue){
-    lastFrameTime = audioOk ? now : now - (elapsed % targetMs);
+  if (elapsed >= target){
+    lastFrameTime = now - (elapsed % targetMs);
     try{
       updateRect();
       meterHitRects.length = 0;