/* * AudioFilterFIR_F32 * * Created: Chip Audette (OpenAudio) Feb 2017 * - Building from AudioFilterFIR from Teensy Audio Library (AudioFilterFIR credited to Pete (El Supremo)) * */ #ifndef _filter_fir_f32_h #define _filter_fir_f32_h #include "Arduino.h" #include "AudioStream_F32.h" #include "arm_math.h" // Indicates that the code should just pass through the audio // without any filtering (as opposed to doing nothing at all) #define FIR_F32_PASSTHRU ((const float32_t *) 1) #define FIR_MAX_COEFFS 200 class AudioFilterFIR_F32 : public AudioStream_F32 { //GUI: inputs:1, outputs:1 //this line used for automatic generation of GUI node public: AudioFilterFIR_F32(void): AudioStream_F32(1,inputQueueArray), coeff_p(FIR_F32_PASSTHRU) { } void begin(const float32_t *cp, int n_coeffs) { coeff_p = cp; // Initialize FIR instance (ARM DSP Math Library) if (coeff_p && (coeff_p != FIR_F32_PASSTHRU) && n_coeffs <= FIR_MAX_COEFFS) { arm_fir_init_f32(&fir_inst, n_coeffs, (float32_t *)coeff_p, &StateF32[0], AUDIO_BLOCK_SAMPLES); //if (arm_fir_init_f32(&fir_inst, n_coeffs, (float32_t *)coeff_p, &StateF32[0], AUDIO_BLOCK_SAMPLES) != ARM_MATH_SUCCESS) { // n_coeffs must be an even number, 4 or larger //coeff_p = NULL; //} } } void end(void) { coeff_p = NULL; } virtual void update(void); void setBlockDC(void) { //helper function that sets this up for a first-order HP filter at 20Hz } private: audio_block_f32_t *inputQueueArray[1]; // pointer to current coefficients or NULL or FIR_PASSTHRU const float32_t *coeff_p; // ARM DSP Math library filter instance arm_fir_instance_f32 fir_inst; float32_t StateF32[AUDIO_BLOCK_SAMPLES + FIR_MAX_COEFFS]; }; void AudioFilterFIR_F32::update(void) { audio_block_f32_t *block, *b_new; block = AudioStream_F32::receiveReadOnly_f32(); if (!block) return; // If there's no coefficient table, give up. if (coeff_p == NULL) { AudioStream_F32::release(block); return; } // do passthru if (coeff_p == FIR_F32_PASSTHRU) { // Just passthrough AudioStream_F32::transmit(block); AudioStream_F32::release(block); return; } // get a block for the FIR output b_new = AudioStream_F32::allocate_f32(); if (b_new) { arm_fir_f32(&fir_inst, (float32_t *)block->data, (float32_t *)b_new->data, block->length); AudioStream_F32::transmit(b_new); // send the FIR output AudioStream_F32::release(b_new); } AudioStream_F32::release(block); } #endif