#ifndef _AudioConvert_I16toF32 #define _AudioConvert_I16toF32 #include class AudioConvert_I16toF32 : public AudioStream_F32 //receive Int and transmits Float { public: AudioConvert_I16toF32(void) : AudioStream_F32(1, inputQueueArray_f32) { }; void update(void) { //get the Int16 block audio_block_t *int_block; int_block = AudioStream::receiveReadOnly(); //int16 data block if (!int_block) return; //allocate a float block audio_block_f32_t *float_block; float_block = AudioStream_F32::allocate_f32(); if (float_block == NULL) return; //convert to float convertAudio_I16toF32(int_block, float_block, AUDIO_BLOCK_SAMPLES); //transmit the audio and return it to the system AudioStream_F32::transmit(float_block,0); AudioStream_F32::release(float_block); AudioStream::release(int_block); }; static void convertAudio_I16toF32(audio_block_t *in, audio_block_f32_t *out, int len) { //WEA Method. Should look at CMSIS arm_q15_to_float instead: https://www.keil.com/pack/doc/CMSIS/DSP/html/group__q15__to__x.html#gaf8b0d2324de273fc430b0e61ad4e9eb2 const float MAX_INT = 32678.0; for (int i = 0; i < len; i++) out->data[i] = (float)(in->data[i]); arm_scale_f32(out->data, 1.0/MAX_INT, out->data, out->length); //divide by 32678 to get -1.0 to +1.0 } private: audio_block_f32_t *inputQueueArray_f32[1]; //2 for stereo }; class AudioConvert_F32toI16 : public AudioStream_F32 //receive Float and transmits Int { public: AudioConvert_F32toI16(void) : AudioStream_F32(1, inputQueueArray_Float) {}; void update(void) { //get the float block audio_block_f32_t *float_block; float_block = AudioStream_F32::receiveReadOnly_f32(); //float data block if (!float_block) return; //allocate a Int16 block audio_block_t *int_block; int_block = AudioStream::allocate(); if (int_block == NULL) return; //convert back to int16 convertAudio_F32toI16(float_block, int_block, AUDIO_BLOCK_SAMPLES); //return audio to the system AudioStream::transmit(int_block); AudioStream::release(int_block); AudioStream_F32::release(float_block); }; static void convertAudio_F32toI16(audio_block_f32_t *in, audio_block_t *out, int len) { //WEA Method. Should look at CMSIS arm_float_to_q15 instead: https://www.keil.com/pack/doc/CMSIS/DSP/html/group__float__to__x.html#ga215456e35a18db86882e1d3f0d24e1f2 const float MAX_INT = 32678.0; for (int i = 0; i < len; i++) { out->data[i] = (int16_t)(max(min( (in->data[i] * MAX_INT), MAX_INT), -MAX_INT)); } } private: audio_block_f32_t *inputQueueArray_Float[1]; }; #endif