Slightly improved distort.c.

c/distort.c

@@ -6,18 +6,22 @@
 
 #define BUFFER_LEN  1024
 
+void applyOverdriveDistortion (SNDFILE *inputFile, SNDFILE *outputFile);
+void applyFuzzDistortion      (SNDFILE *inputFile, SNDFILE *outputFile);
+void applyDistortion          (SNDFILE *inputFile, SNDFILE *outputFile);
+void applyBoostDistortion     (SNDFILE *inputFile, SNDFILE *outputFile, float gain);
+
 int main(int argc, char **argv) {
 	int    distortionLevel;
 	SNDFILE *infile, *outfile;
 	SF_INFO sfinfo;
-	double buffer[BUFFER_LEN];
 
 	// Check for distortion level argument
-	if (argc < 2) {
+	if (argc < 3) {
-		printf("Usage: %s distortion_level\n", argv[0]);
+		printf("Usage: %s distortion-type distortion_level\n", argv[0]);
 		return 1;
 	}
-	distortionLevel = atoi(argv[1]);
+	distortionLevel = atoi(argv[2]);
 
 	// Open standard input as input file
 	if (!(infile = sf_open_fd(0, SFM_READ, &sfinfo, 0))) {
@@ -31,16 +35,34 @@ int main(int argc, char **argv) {
 		return 1;
 	}
 
-	// Read and process data
+	if (memcmp(argv[1], "overdrive", strlen("overdrive")) == 0) {
-	while (sf_read_double(infile, buffer, BUFFER_LEN) > 0) {
+		fprintf(stderr, "overdrive\n");
-		for (int i=0; i<BUFFER_LEN; i++) {
+		applyOverdriveDistortion(infile, outfile);
-			// Add distortion to the sample
-			buffer[i] = buffer[i] * (1.0 + (distortionLevel/100.0) * sin(2.0 * M_PI * buffer[i]));
-		}
-
-		// Write the processed sample to the output file
-		sf_write_double(outfile, buffer, BUFFER_LEN);
 	}
+	if (memcmp(argv[1], "fuzz", strlen("fuzz")) == 0) {
+		fprintf(stderr, "fuzz\n");
+		applyFuzzDistortion(infile, outfile);
+	}
+	if (memcmp(argv[1], "distortion", strlen("distortion")) == 0) {
+		fprintf(stderr, "distortion\n");
+		applyDistortion(infile, outfile);
+	}
+	if (memcmp(argv[1], "boost", strlen("boost")) == 0) {
+		fprintf(stderr, "boost\n");
+		applyBoostDistortion(infile, outfile, distortionLevel);
+	}
+
+//	// Read and process data
+//	double buffer[BUFFER_LEN];
+//	while (sf_read_double(infile, buffer, BUFFER_LEN) > 0) {
+//		for (int i=0; i<BUFFER_LEN; i++) {
+//			// Add distortion to the sample
+//			buffer[i] = buffer[i] * (1.0 + (distortionLevel/100.0) * sin(2.0 * M_PI * buffer[i]));
+//		}
+//
+//		// Write the processed sample to the output file
+//		sf_write_double(outfile, buffer, BUFFER_LEN);
+//	}
 
 	// Close files
 	sf_close(infile);
@@ -48,3 +70,86 @@ int main(int argc, char **argv) {
 
 	return 0;
 }
+
+// TODO: use these functions
+
+// function to apply overdrive distortion to an audio signal using sndfile API
+void applyOverdriveDistortion(SNDFILE *inputFile, SNDFILE *outputFile)
+{
+    // read in the data from the input file
+    int bufferSize = 1024;
+    float *inputBuffer = malloc(bufferSize * sizeof(float));
+    int framesRead;
+    while ((framesRead = sf_readf_float(inputFile, inputBuffer, bufferSize))) {
+        // apply overdrive distortion
+        for (int i = 0; i < framesRead; i++) {
+            float x = inputBuffer[i];
+            float y = (1 + x) * (1 + x) / (1 + 2 * x + x * x);
+            inputBuffer[i] = y;
+        }
+        // write processed data to output file
+        sf_writef_float(outputFile, inputBuffer, framesRead);
+    }
+    free(inputBuffer);
+}
+
+// function to apply fuzz distortion to an audio signal using sndfile API
+void applyFuzzDistortion(SNDFILE *inputFile, SNDFILE *outputFile)
+{
+    // read in the data from the input file
+    int bufferSize = 1024;
+    float *inputBuffer = malloc(bufferSize * sizeof(float));
+    int framesRead;
+    while ((framesRead = sf_readf_float(inputFile, inputBuffer, bufferSize))) {
+        // apply fuzz distortion
+        for (int i = 0; i < framesRead; i++) {
+            float x = inputBuffer[i];
+            float y = x / (1 + fabs(x));
+            inputBuffer[i] = y;
+        }
+        // write processed data to output file
+        sf_writef_float(outputFile, inputBuffer, framesRead);
+    }
+    free(inputBuffer);
+}
+
+// function to apply distortion to an audio signal using sndfile API
+void applyDistortion(SNDFILE *inputFile, SNDFILE *outputFile)
+{
+    // read in the data from the input file
+    int bufferSize = 1024;
+    float *inputBuffer = malloc(bufferSize * sizeof(float));
+    int framesRead;
+    while ((framesRead = sf_readf_float(inputFile, inputBuffer, bufferSize))) {
+        // apply distortion
+        for (int i = 0; i < framesRead; i++) {
+            float x = inputBuffer[i];
+            float y = x / (1 + fabs(x));
+            y = y * 0.5 + 0.5;
+            inputBuffer[i] = y;
+        }
+        // write processed data to output file
+        sf_writef_float(outputFile, inputBuffer, framesRead);
+    }
+    free(inputBuffer);
+}
+
+// function to apply boost to an audio signal using sndfile API
+void applyBoostDistortion(SNDFILE *inputFile, SNDFILE *outputFile, float gain)
+{
+    // read in the data from the input file
+    int bufferSize = 1024;
+    float *inputBuffer = malloc(bufferSize * sizeof(float));
+    int framesRead;
+    while ((framesRead = sf_readf_float(inputFile, inputBuffer, bufferSize))) {
+        // apply boost
+        for (int i = 0; i < framesRead; i++) {
+            float x = inputBuffer[i];
+            float y = x * gain;
+            inputBuffer[i] = y;
+        }
+        // write processed data to output file
+        sf_writef_float(outputFile, inputBuffer, framesRead);
+    }
+    free(inputBuffer);
+}