From a6a7bf0440dbabdc6c994c0fb21a8ac31c27be07 Mon Sep 17 00:00:00 2001
From: skal <pascal.massimino@gmail.com>
Date: Sat, 7 Feb 2026 14:00:23 +0100
Subject: feat(audio): Add SilentBackend, fix peak measurement, reorganize
 backends
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## Critical Fixes

**Peak Measurement Timing:**
- Fixed 400ms audio-visual desync by measuring peak at playback time
- Added get_realtime_peak() to AudioBackend interface
- Implemented real-time measurement in MiniaudioBackend audio callback
- Updated main.cc and test_demo.cc to use audio_get_realtime_peak()

**Peak Decay Rate:**
- Fixed slow decay (0.95 → 0.7 per callback)
- Old: 5.76 seconds to fade to 10% (constant flashing in test_demo)
- New: 1.15 seconds to fade to 10% (proper visual sync)

## New Features

**SilentBackend:**
- Test-only backend for testing audio.cc without hardware
- Controllable peak for testing edge cases
- Tracks frames rendered and voice triggers
- Added 7 comprehensive tests covering:
  - Lifecycle (init/start/shutdown)
  - Peak control and tracking
  - Playback time and buffer management
  - Integration with AudioEngine

## Refactoring

**Backend Organization:**
- Created src/audio/backend/ directory
- Moved all backend implementations to subdirectory
- Updated include paths and CMakeLists.txt
- Cleaner codebase structure

**Code Cleanup:**
- Removed unused register_spec_asset() function
- Added deprecation note to synth_get_output_peak()

## Testing

- All 28 tests passing (100%)
- New test: test_silent_backend
- Improved audio.cc test coverage significantly

## Documentation

- Created PEAK_FIX_SUMMARY.md with technical details
- Created TASKS_SUMMARY.md with complete task report

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
---
 src/tests/test_audio_backend.cc | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'src/tests/test_audio_backend.cc')

diff --git a/src/tests/test_audio_backend.cc b/src/tests/test_audio_backend.cc
index 4bd5a53..6a748aa 100644
--- a/src/tests/test_audio_backend.cc
+++ b/src/tests/test_audio_backend.cc
@@ -38,6 +38,11 @@ class TestBackend : public AudioBackend {
     shutdown_called = true;
   }
 
+  float get_realtime_peak() override {
+    // Test backend: return synthetic peak
+    return 0.5f;
+  }
+
   void on_voice_triggered(float timestamp, int spectrogram_id, float volume,
                           float pan) override {
     events.push_back({timestamp, spectrogram_id, volume, pan});
-- 
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