wave.c

#include <stdio.h>
#include "wave.h" // double quotation marks are used for user defined header
#include <math.h>
#include "screen.h"
#include "comm.h"

void printID(char s[]){
        int i;
        for(i=1; i<4; i++) putchar(s[i]);
        printf("\n");
}

void    fillID(char *d, const char s[]){
        int i;
        for (i=0; i<4; i++) *d++=s[i];
}

void testTone(int f, double d){
        WAVHDR h;
        FILE *fp;
        int i;
        short int sample;
        fillID(h.ChunkID, "RIFF");
        fillID(h.Format, "WAVE");
        fillID(h.Subchunk1ID, "fmt ");
        fillID(h.Subchunk2ID, "data");
        //chunk size will be calculated later
        h.Subchunk1Size = 16;
        h.AudioFormat = 1;
        h.NumChannels = 1;
        h.SampleRate = SAMPLE_RATE;
        h.BitsperSample = 16;
        h.ByteRate = SAMPLE_RATE*h.NumChannels*(h.BitsperSample/8);
        h.BlockAlign = h.NumChannels*h.BitsperSample/8;
        h.Subchunk2Size = h.ByteRate * d;
        h.ChunkSize = h.Subchunk2Size + 36;
        fp = fopen("testtone.wav", "w");
        fwrite(&h, sizeof(h), 1, fp);   //wite the header to file
        for(i=0; i<SAMPLE_RATE*d; i++){
                sample = 32767 *sin(2*PI*f*i/SAMPLE_RATE);
                fwrite(&sample, sizeof(sample), 1, fp);
        }
        fclose(fp);
        printf("Test tone created!\n");
}

void dispWAVHDR(WAVHDR h){
        double  duration;
        duration = (double)h.Subchunk2Size/h.ByteRate;

#ifdef DEBUG
        printf("Chunk ID: "); printID(h.ChunkID);
        printf("Chunk size: %d\n", h.ChunkSize);
        printf("Format: "); printID(h.Format);
        printf("Subchunk1 ID: "); printID(h.Subchunk1ID);
        printf("Subchunk1 size: %d\n", h.Subchunk1Size);
        printf("Audio format: %d\n", h.AudioFormat);
        printf("Num of Channels: %d\n", h.NumChannels);
        printf("Sample rat: %d\n", h.SampleRate);
        printf("Byte rate: %d\n", h.ByteRate);
        printf("Block Align: %d\n", h.BlockAlign);
        printf("Bits / Sample: %d\n", h.BitsperSample);
        printf("Subchunk2 ID: "); printID(h.Subchunk2ID);
        printf("Subchunk2 size: %d\n", h.Subchunk2Size);
        printf("Duration: %.3f sec\n", duration);
#else
	gotoXY(1,1); setFGcolor(RED); printf("%.2f", duration);
	gotoXY(1,10); setFGcolor(CYAN); printf("%d bits/s", h.BitsperSample);
	gotoXY(1,20); setFGcolor(YELLOW); printf("%d sps", h.SampleRate);
	resetColors();
	fflush(stdout);
#endif
}

// function dispWAVdata calculates 1-sec samples into 80 pieces
// of RMS value, each RMS value is calculated from 16000/80=200
// pieces of sample. See wiki pare for "RMS"
// However, only 8 pieces of RMS data are sent to the server as Fast Mode 
// of Sound Level Meter (SLM)
void dispWAVdata(short int s[]){
	int i, j;
	double sum200, rms200;
	// the following vars are used to calculate short Leq
	double Leq[8], sum8=0.0;
	
	for(i=0; i<80; i++){	//outer loop for 80 times
		sum200 = 0.0;
		for(j=0; j < SAMPLE_RATE/80; j++){
			sum200 += (*s)*(*s);
			s++;
		}
		sum8 += sum200; // accumulate current sum200 to sum8
		if(i%10==9){
			Leq[i/10]=sqrt(sum8/(SAMPLE_RATE/8));
			sum8=0.0; // reset sum8 for next Leq value
		}
		
		rms200 = sqrt(sum200/200);
#ifdef DEBUG	//conditional compiling
		printf("%2d: %10.2f ", i, rms200);
#else
		//display vertical bars
		displayBar(i+1, rms200);
#endif
	} //end of for(i)
#ifdef COMM
	send_data(Leq);
#endif
}