1 files changed, 12 insertions, 9 deletions
diff --git a/src/audio/wav_dump_backend.cc b/src/audio/wav_dump_backend.cc
index f5ea9d7..bcf43c0 100644
--- a/src/audio/wav_dump_backend.cc
+++ b/src/audio/wav_dump_backend.cc
@@ -48,7 +48,8 @@ void WavDumpBackend::start() {
   // This matches the seek logic in main.cc
   const int max_duration_sec = 60;
   const float update_dt = 1.0f / 60.0f;  // 60Hz update rate (matches main loop)
-  const int samples_per_update = (int)(kSampleRate * update_dt);  // ~533 samples
+  const int frames_per_update = (int)(kSampleRate * update_dt);  // ~533 frames
+  const int samples_per_update = frames_per_update * 2;  // Stereo: 2 samples per frame
   const int total_updates = (int)(max_duration_sec / update_dt);
 
   // Music time tracking
@@ -56,7 +57,7 @@ void WavDumpBackend::start() {
   float tempo_scale = 1.0f;
   float physical_time = 0.0f;
 
-  // Temporary buffer for each update chunk
+  // Temporary buffer for each update chunk (stereo)
   std::vector<float> chunk_buffer(samples_per_update);
 
   for (int update_count = 0; update_count < total_updates; ++update_count) {
@@ -83,9 +84,10 @@ void WavDumpBackend::start() {
     tracker_update(music_time);
 
     // Render audio immediately after tracker update (keeps synth time in sync)
-    synth_render(chunk_buffer.data(), samples_per_update);
+    // Note: synth_render expects number of FRAMES, outputs stereo (2 samples/frame)
+    synth_render(chunk_buffer.data(), frames_per_update);
 
-    // Convert float to int16 and write to WAV
+    // Convert float to int16 and write to WAV (stereo interleaved)
     for (int i = 0; i < samples_per_update; ++i) {
       float sample = chunk_buffer[i];
       if (sample > 1.0f) sample = 1.0f;
@@ -104,12 +106,13 @@ void WavDumpBackend::start() {
       fflush(stdout);
     }
 
-    // Call frame rendering hook
-    on_frames_rendered(samples_per_update);
+    // Call frame rendering hook (pass frames, not samples)
+    on_frames_rendered(frames_per_update);
   }
 
-  printf("\nWAV dump complete: %zu samples (%.2f seconds, %.2f music time)\n",
-         samples_written_, (float)samples_written_ / kSampleRate, music_time);
+  printf(
+      "\nWAV dump complete: %zu samples (%.2f seconds stereo, %.2f music time)\n",
+      samples_written_, (float)samples_written_ / (kSampleRate * 2), music_time);
 
   is_active_ = false;
 }
@@ -129,7 +132,7 @@ void WavDumpBackend::write_wav_header(FILE* file, uint32_t num_samples) {
   // WAV file header structure
   // Reference: http://soundfile.sapp.org/doc/WaveFormat/
 
-  const uint32_t num_channels = 1;  // Mono
+  const uint32_t num_channels = 2;  // Stereo (matches miniaudio config)
   const uint32_t sample_rate = kSampleRate;
   const uint32_t bits_per_sample = 16;
   const uint32_t byte_rate = sample_rate * num_channels * bits_per_sample / 8;