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use memory aligned allocations, fix bug in FFT magnitude (integer path) #5499

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Merged
DedeHai merged 2 commits into from
Apr 12, 2026
+20 −17
Merged

use memory aligned allocations, fix bug in FFT magnitude (integer path) #5499

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aa5a409
use memory aligned allocations, fix bug in FFT magnitude (integer path)
DedeHai Apr 12, 2026
72da547
assign pointer to globals not local copy
DedeHai Apr 12, 2026
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37 changes: 20 additions & 17 deletions usermods/audioreactive/audio_reactive.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -296,17 +296,17 @@ void FFTcode(void * parameter)
ArduinoFFT<float> FFT = ArduinoFFT<float>(valFFT, vImag, samplesFFT, SAMPLE_RATE, true);
#elif !defined(UM_AUDIOREACTIVE_USE_INTEGER_FFT)
// allocate and initialize FFT buffers on first call
// note: free() is never used on these pointers. If it ever is implemented, this implementation can cause memory leaks (need to free raw pointers)
if (valFFT == nullptr) {
float* raw_buffer = (float*)heap_caps_malloc((2 * samplesFFT * sizeof(float)) + 16, MALLOC_CAP_8BIT);
if ((raw_buffer == nullptr)) return; // something went wrong
valFFT = (float*)(((uintptr_t)raw_buffer + 15) & ~15); // SIMD requires aligned memory to 16-byte boundary. note in IDF5 there is MALLOC_CAP_SIMD available
valFFT = (float*)heap_caps_aligned_calloc(16, 2 * samplesFFT, sizeof(float), MALLOC_CAP_8BIT); // SIMD requires aligned memory to 16-byte boundary. note in IDF5 there is MALLOC_CAP_SIMD available
if ((valFFT == nullptr)) return; // something went wrong
}
// create window
if (windowFFT == nullptr) {
float* raw_buffer = (float*)heap_caps_malloc((samplesFFT * sizeof(float)) + 16, MALLOC_CAP_8BIT);
if ((raw_buffer == nullptr)) return; // something went wrong
windowFFT = (float*)(((uintptr_t)raw_buffer + 15) & ~15); // SIMD requires aligned memory to 16-byte boundary
windowFFT = (float*)heap_caps_aligned_calloc(16, samplesFFT, sizeof(float), MALLOC_CAP_8BIT); // SIMD requires aligned memory to 16-byte boundary. note in IDF5 there is MALLOC_CAP_SIMD available
if ((windowFFT == nullptr)) {
heap_caps_free(valFFT); valFFT = nullptr;
return; // something went wrong
}
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}
if (dsps_fft2r_init_fc32(NULL, samplesFFT) != ESP_OK) return; // initialize FFT tables
// create window function for FFT
Expand All @@ -316,16 +316,20 @@ void FFTcode(void * parameter)
dsps_wind_flat_top_f32(windowFFT, samplesFFT);
#endif
#else
// allocate and initialize integer FFT buffers on first call
if (valFFT == nullptr) valFFT = (int16_t*) calloc(sizeof(int16_t), samplesFFT * 2);
if ((valFFT == nullptr)) return; // something went wrong
// use integer FFT - allocate and initialize integer FFT buffers on first call, 4 bytes aligned (just in case, even if not strictly needed for int16_t)
if (valFFT == nullptr) valFFT = (int16_t*) heap_caps_aligned_calloc(4, samplesFFT * 2, sizeof(int16_t), MALLOC_CAP_8BIT);
// create window
if (windowFFT == nullptr) windowFFT = (int16_t*) calloc(sizeof(int16_t), samplesFFT);
if ((windowFFT == nullptr)) return; // something went wrong
if (dsps_fft2r_init_sc16(NULL, samplesFFT) != ESP_OK) return; // initialize FFT tables
if (windowFFT == nullptr) windowFFT = (int16_t*) heap_caps_aligned_calloc(4, samplesFFT, sizeof(int16_t), MALLOC_CAP_8BIT);
// create window function for FFT
float *windowFloat = (float*) calloc(sizeof(float), samplesFFT); // temporary buffer for window function
if ((windowFloat == nullptr)) return; // something went wrong
float *windowFloat = (float*) heap_caps_aligned_calloc(4, samplesFFT, sizeof(float), MALLOC_CAP_8BIT); // temporary buffer for window function
if (windowFloat == nullptr || windowFFT == nullptr || valFFT == nullptr) { // something went wrong
if (windowFloat) heap_caps_free(windowFloat);
if (windowFFT) heap_caps_free(windowFFT); windowFFT = nullptr;
if (valFFT) heap_caps_free(valFFT); valFFT = nullptr;
return;
}
if (dsps_fft2r_init_sc16(NULL, samplesFFT) != ESP_OK) return; // initialize FFT tables

#ifdef FFT_PREFER_EXACT_PEAKS
dsps_wind_blackman_harris_f32(windowFloat, samplesFFT);
#else
Expand All @@ -335,7 +339,7 @@ void FFTcode(void * parameter)
for (int i = 0; i < samplesFFT; i++) {
windowFFT[i] = (int16_t)(windowFloat[i] * 32767.0f);
}
free(windowFloat); // free temporary buffer
heap_caps_free(windowFloat); // free temporary buffer
#endif

// see https://www.freertos.org/vtaskdelayuntil.html
Expand Down Expand Up @@ -468,7 +472,6 @@ void FFTcode(void * parameter)
}
FFT_Magnitude = FFT_Magnitude_int * 512; // scale to match raw float value
FFT_MajorPeak = FFT_MajorPeak_int;
FFT_Magnitude = FFT_Magnitude_int;
#endif
#endif
FFT_MajorPeak = constrain(FFT_MajorPeak, 1.0f, 11025.0f); // restrict value to range expected by effects
Expand Down
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