I have a confusing problem that's happening to me, ill explain it to the best of my abilities with code, text, all that good stuff.
THE PROBLEM:
I have a laptop that uses its in-line output into an ADC. The ADC then goes into my STM32H7 MCU. The MCU processes the audio signal using the CMSIS DSP LIBRARY. Once done doing the signal processing it shoots the newly filter data into the DAC from there the DAC is then connected to my headphones via an auxiliary cable.
When I play a music file that has stereo I hear it in both speakers of my headphone. Using this site as reference. Site I used to check for stereo
DIAGRAM:
WHAT I FOUND:
I got it working but without using the DSP library, which is not a good thing as the DSP is needed here. Somehow the DSP library is adding the two channels together or mixing the two and I have no idea how.
Sample codes that got stereo working:
1.
void prcoess_inline_halfSample(int * RxBuff_inline, int * TxBuff_inline, float * inSample_inline_L, float * inSample_inline_R,
float * outSample_inline_L, float * outSample_inline_R, float scaleFactor, uint8_t volumeCurrent,
arm_biquad_casd_df1_inst_f32 * audioStream_L, arm_biquad_casd_df1_inst_f32 * audioStream_R,
float inputCompensator) {
for (int i = 0; i < 2; i ++){
TxBuff_inline[i] = RxBuff_inline[i];
}
}
void process_inline_CompleteSample(int * RxBuff_inline, int * TxBuff_inline, float * inSample_inline_L, float * inSample_inline_R,
float * outSample_inline_L, float * outSample_inline_R,float scaleFactor, uint8_t volumeCurrent,
arm_biquad_casd_df1_inst_f32 * audioStream_L, arm_biquad_casd_df1_inst_f32 * audioStream_R,
float inputCompensator) {
for (int i = 2; i < 4; i ++){
TxBuff_inline[i] = RxBuff_inline[i];
}
}
void prcoess_inline_halfSample(int * RxBuff_inline, int * TxBuff_inline, float * inSample_inline_L, float * inSample_inline_R,
float * outSample_inline_L, float * outSample_inline_R, float scaleFactor, uint8_t volumeCurrent,
arm_biquad_casd_df1_inst_f32 * audioStream_L, arm_biquad_casd_df1_inst_f32 * audioStream_R,
float inputCompensator) {
for (int i = 0; i < 2; i ++){
if (i % 2 == 0){ // L Samples
inSample_inline_L[i] = (float) RxBuff_inline[i] * (scaleFactor * (float) volumeCurrent) * inputCompensator;
} else if ( i % 2 == 1){ // R Samples
inSample_inline_R[i-1] = (float) RxBuff_inline[i] * (scaleFactor * (float) volumeCurrent) * inputCompensator;
}
}
//arm_biquad_cascade_df1_f32(audioStream_L, inSample_inline_L, outSample_inline_L, 1);
//arm_biquad_cascade_df1_f32(audioStream_R, inSample_inline_R, outSample_inline_R, 1);
for (int i = 0; i < 2; i ++){
if (i % 2 == 0) { // L Samples
TxBuff_inline[i] = (int)inSample_inline_L[i];
} else if ( i % 2 == 1) { // R Samples
TxBuff_inline[i] = (int)inSample_inline_R[i-1];
}
}
}
void process_inline_CompleteSample(int * RxBuff_inline, int * TxBuff_inline, float * inSample_inline_L, float * inSample_inline_R,
float * outSample_inline_L, float * outSample_inline_R,float scaleFactor, uint8_t volumeCurrent,
arm_biquad_casd_df1_inst_f32 * audioStream_L, arm_biquad_casd_df1_inst_f32 * audioStream_R,
float inputCompensator) {
for (int i = 2; i < 4; i ++){
if (i % 2 == 0){ // L Samples
inSample_inline_L[i-1] = (float) RxBuff_inline[i] * (scaleFactor * (float) volumeCurrent) * inputCompensator;
} else if ( i % 2 == 1){ // R Samples
inSample_inline_R[i-2] = (float) RxBuff_inline[i] * (scaleFactor * (float) volumeCurrent) * inputCompensator;
}
}
//arm_biquad_cascade_df1_f32(audioStream_L, &inSample_inline_L[1], &outSample_inline_L[1], 1);
//arm_biquad_cascade_df1_f32(audioStream_R, &inSample_inline_R[1], &outSample_inline_R[1], 1);
for (int i = 2; i < 4; i ++){
if (i % 2 == 0) { // L Samples
TxBuff_inline[i] = (int)inSample_inline_L[i-1];
} else if ( i % 2 == 1) { // R Samples
TxBuff_inline[i] = (int)inSample_inline_R[i-2];
}
}
}
What this tells me is that I have my indexing correct, and my L and R channels positioned properly in the buffer to be transmitted to the DAC. Its something up with the DSP library for some reason.
ORIGINAL CODE:
void prcoess_inline_halfSample(int * RxBuff_inline, int * TxBuff_inline, float * inSample_inline_L, float * inSample_inline_R,
float * outSample_inline_L, float * outSample_inline_R, float scaleFactor, uint8_t volumeCurrent,
arm_biquad_casd_df1_inst_f32 * audioStream_L, arm_biquad_casd_df1_inst_f32 * audioStream_R,
float inputCompensator) {
for (int i = 0; i < 2; i ++){
if (i % 2 == 0){ // L Samples
inSample_inline_L[i] = (float) RxBuff_inline[i] * (scaleFactor * (float) volumeCurrent) * inputCompensator;
} else if ( i % 2 == 1){ // R Samples
inSample_inline_R[i-1] = (float) RxBuff_inline[i] * (scaleFactor * (float) volumeCurrent) * inputCompensator;
}
}
arm_biquad_cascade_df1_f32(audioStream_L, inSample_inline_L, outSample_inline_L, 1);
arm_biquad_cascade_df1_f32(audioStream_R, inSample_inline_R, outSample_inline_R, 1);
for (int i = 0; i < 2; i ++){
if (i % 2 == 0) { // L Samples
TxBuff_inline[i] = (int)outSample_inline_L[i];
} else if ( i % 2 == 1) { // R Samples
TxBuff_inline[i] = (int)outSample_inline_R[i-1];
}
}
}
void process_inline_CompleteSample(int * RxBuff_inline, int * TxBuff_inline, float * inSample_inline_L, float * inSample_inline_R,
float * outSample_inline_L, float * outSample_inline_R,float scaleFactor, uint8_t volumeCurrent,
arm_biquad_casd_df1_inst_f32 * audioStream_L, arm_biquad_casd_df1_inst_f32 * audioStream_R,
float inputCompensator) {
for (int i = 2; i < 4; i ++){
if (i % 2 == 0){ // L Samples
inSample_inline_L[i-1] = (float) RxBuff_inline[i] * (scaleFactor * (float) volumeCurrent) * inputCompensator;
} else if ( i % 2 == 1){ // R Samples
inSample_inline_R[i-2] = (float) RxBuff_inline[i] * (scaleFactor * (float) volumeCurrent) * inputCompensator;
}
}
arm_biquad_cascade_df1_f32(audioStream_L, &inSample_inline_L[1], &outSample_inline_L[1], 1);
arm_biquad_cascade_df1_f32(audioStream_R, &inSample_inline_R[1], &outSample_inline_R[1], 1);
for (int i = 2; i < 4; i ++){
if (i % 2 == 0) { // L Samples
TxBuff_inline[i] = (int)outSample_inline_L[i-1];
} else if ( i % 2 == 1) { // R Samples
TxBuff_inline[i] = (int)outSample_inline_R[i-2];
}
}
}
Any ideas what could be causing this?
