AudioConvert: comment to CMSIS conversion instead

pull/1/head
Chip Audette 8 years ago
parent 97b5cb96f6
commit 85a0271afc
  1. 5
      AudioConvert_F32.h

@ -33,8 +33,9 @@ class AudioConvert_I16toF32 : public AudioStream_F32 //receive Int and transmits
audio_block_f32_t *inputQueueArray_f32[1]; //2 for stereo
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])/MAX_INT;
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
}
@ -68,6 +69,8 @@ class AudioConvert_F32toI16 : public AudioStream_F32 //receive Float and transmi
private:
audio_block_f32_t *inputQueueArray_Float[1];
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));

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