Audio effects implementation

1. Audio effects implementation ECE 3551 – Microcomputer Systems I By AbdulrahmanBin Humood

2. Overview • This project was created to use the OMAP L137 Texas Instruments DSP Board to control audio outputand display some audio effects that have been taught during the course of the class.

3. Code Imlementation • switch(mode) • { • case 1: • Passthrough(pIn, pOut); • break; • case 2: • Process_Data(pIn, pOut); • Delay(pIn, pOut); • break; • case 3: • Process_Data(pIn, pOut); • Vibrato(pIn, pOut); • break; • default: • Passthrough(pIn, pOut); • break; • }

4. Delay Code • void Delay(short *pIn, short *pOut) //Applies delay effect to signal. • { inti; • for (i = 0; i < BUFLEN; i++) • { • int delay = temp - (2000 - 20); • buffer_in2[temp] = pIn[i * 2]; • buffer_in1[temp] = pIn[i * 2 + 1]; • if ( delay < 0 ) • { • delay = delay + 2000; • } • output1 = buffer_in1[temp] + 0.9 * buffer_in1[delay]; • output2 = buffer_in2[temp] + 0.9 * buffer_in2[delay]; • pOut[i * 2] = (short)output1; • pOut[i * 2 + 1] = (short)output2; • temp++; • temp = temp % 2000; • } • }

5. Vibrato Code • void Vibrato(short *pIn, short *pOut) • { • inti; • for (i = 0; i < BUFLEN; i++) • { • var_time_delay = (int)(0.5 * (1 + cos (2 * 3.14 * 0.4 * temp / 2000)) * BUFSIZE); • var_delay = temp - var_time_delay; • buffer_in1[temp] = pIn[i * 2 + 1]; • buffer_in2[temp] = pIn[i * 2]; • if (var_delay < 0) • { • var_delay = var_delay + 2000; • } • output1 = buffer_in1[temp] + 0.6 * (buffer_in1[var_delay]); // implementation equation of vibrato effect • output2 = buffer_in2[temp] + 0.6 * (buffer_in2[var_delay]); // implementation of vibrato effect • pOut[i * 2] = output1; • pOut[i * 2 + 1] = output2; • temp++; • temp = temp % 2000; • }}

6. END • THANK YOU!