From df1f6788455ade06bd39bc41d77645cae698b3d4 Mon Sep 17 00:00:00 2001
From: Ashley Strahle <ash@jackofclubs.com.au>
Date: Fri, 3 Jul 2026 07:53:04 +0000
Subject: [PATCH] Add 20ms flash latency to compensate for audio buffer (flash
 was ahead of beat)

---
 src/main.cpp | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 48d8a1c..56c4cc7 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -29,6 +29,7 @@ void midi_task(void* parameter) {
     // Beat timing fixes for precise beat alignment - sync to real MIDI time, not hardcoded tempo
     uint32_t last_beat = 0;
     uint32_t flash_start = 0;
+    const uint32_t FLASH_LATENCY = 20; // ms delay to compensate for audio buffer
 
     while (true) {
         midi_transport.update();
@@ -41,20 +42,20 @@ void midi_task(void* parameter) {
 
         if (current_beat != last_beat) {
             last_beat = current_beat;
-            flash_start = now;
+            flash_start = now + FLASH_LATENCY;
             // Beat 1 (every 4th) = RED, others = WHITE
             if (current_beat % 4 == 0) {
                 mux.set_led_color(6, 255, 0, 0);
             } else {
                 mux.set_led_color(6, 255, 255, 255);
             }
-            mux.show();
         }
 
-        // Beat 1 holds red for 100ms, others snap to dim after 50ms
-        if (flash_start > 0) {
+        if (flash_start > 0 && now >= flash_start) {
+            mux.show();
             uint32_t hold = (last_beat % 4 == 0) ? 100 : 50;
-            if (now - flash_start >= hold) {
+            uint32_t elapsed = now - flash_start;
+            if (elapsed >= hold) {
                 mux.set_led_color(6, 20, 20, 20);
                 mux.show();
                 flash_start = 0;