From 46527bcafd06cac3d21377a1fca9a70661477eb4 Mon Sep 17 00:00:00 2001
From: Josef Miegl <josef@miegl.cz>
Date: Fri, 1 Oct 2021 18:10:59 +0200
Subject: [PATCH] rem fm_mpx*

---
 fm_mpx.c | 268 -------------------------------------------------------
 fm_mpx.h |  10 ---
 2 files changed, 278 deletions(-)
 delete mode 100644 fm_mpx.c
 delete mode 100644 fm_mpx.h

diff --git a/fm_mpx.c b/fm_mpx.c
deleted file mode 100644
index 03b93f8..0000000
--- a/fm_mpx.c
+++ /dev/null
@@ -1,268 +0,0 @@
-/*
-    PiFmAdv - Advanced FM transmitter for the Raspberry Pi
-    Copyright (C) 2017 Miegl
-
-    See https://github.com/Miegl/PiFmAdv
-*/
-
-#include <sndfile.h>
-#include <stdlib.h>
-#include <strings.h>
-#include <math.h>
-
-#include "rds.h"
-
-#define PI 3.14159265359
-
-#define FIR_HALF_SIZE 30
-#define FIR_SIZE (2*FIR_HALF_SIZE-1)
-
-size_t length;
-
-// coefficients of the low-pass FIR filter
-double low_pass_fir[FIR_HALF_SIZE];
-
-double carrier_38[] = {0.0, 0.8660254037844386, 0.8660254037844388, 1.2246467991473532e-16, -0.8660254037844384, -0.8660254037844386};
-double carrier_19[] = {0.0, 0.5, 0.8660254037844386, 1.0, 0.8660254037844388, 0.5, 1.2246467991473532e-16, -0.5, -0.8660254037844384, -1.0, -0.8660254037844386, -0.5};
-
-int phase_38 = 0;
-int phase_19 = 0;
-
-double downsample_factor;
-
-double *audio_buffer;
-int audio_index = 0;
-int audio_len = 0;
-double audio_pos;
-
-double fir_buffer_mono[FIR_SIZE] = {0};
-double fir_buffer_stereo[FIR_SIZE] = {0};
-int fir_index = 0;
-int channels;
-
-double *last_buffer_val;
-double preemphasis_prewarp;
-double preemphasis_coefficient;
-
-SNDFILE *inf;
-
-double *alloc_empty_buffer(size_t length) {
-    double *p = malloc(length * sizeof(double));
-    if(p == NULL) return NULL;
-
-    bzero(p, length * sizeof(double));
-
-    return p;
-}
-
-
-
-int fm_mpx_open(char *filename, size_t len, int cutoff_freq, int preemphasis_corner_freq, int srate, int nochan) {
-	length = len;
-
-	if(filename != NULL) {
-		// Open the input file
-		SF_INFO sfinfo;
-
-                if(filename[0] == '-' && srate > 0 && nochan > 0) {
-                        printf("Using stdin for raw audio input at %d Hz.\n",srate);
-        		sfinfo.samplerate = srate;
-        		sfinfo.format = SF_FORMAT_RAW | SF_FORMAT_PCM_16 | SF_ENDIAN_LITTLE;
-        		sfinfo.channels = nochan;
-        		sfinfo.frames = 0;
-                } 
-
-		// stdin or file on the filesystem?
-		if(filename[0] == '-') {
-			if(!(inf = sf_open_fd(fileno(stdin), SFM_READ, &sfinfo, 0))) {
-				fprintf(stderr, "Error: could not open stdin for audio input.\n");
-				return -1;
-			} else {
-				printf("Using stdin for audio input.\n");
-			}
-		} else {
-			if(!(inf = sf_open(filename, SFM_READ, &sfinfo))) {
-				fprintf(stderr, "Error: could not open input file %s.\n", filename);
-				return -1;
-			} else {
-				printf("Using audio file: %s\n", filename);
-			}
-		}
-
-		int in_samplerate = sfinfo.samplerate;
-		downsample_factor = 228000. / in_samplerate;
-
-		printf("Input: %d Hz, upsampling factor: %.2f\n", in_samplerate, downsample_factor);
-
-		channels = sfinfo.channels;
-		if(channels > 1) {
-			printf("%d channels, generating stereo multiplex.\n", channels);
-		} else {
-			printf("1 channel, monophonic operation.\n");
-		}
-
-		// Create the preemphasis
-		last_buffer_val = (double*) malloc(sizeof(double)*channels);
-		for(int i=0; i<channels; i++) last_buffer_val[i] = 0;
-
-		preemphasis_prewarp = tan(PI*preemphasis_corner_freq/in_samplerate);
-		preemphasis_coefficient = (1.0 + (1.0 - preemphasis_prewarp)/(1.0 + preemphasis_prewarp))/2.0;
-		printf("Created preemphasis with cutoff at %.1i Hz\n", preemphasis_corner_freq);
-
-		// Create the low-pass FIR filter
-		if(in_samplerate < cutoff_freq) cutoff_freq = in_samplerate;
-		// Here we divide this coefficient by two because it will be counted twice
-		// when applying the filter
-		low_pass_fir[FIR_HALF_SIZE-1] = 2 * cutoff_freq / 228000 /2;
-
-		// Only store half of the filter since it is symmetric
-		for(int i=1; i<FIR_HALF_SIZE; i++) {
-			low_pass_fir[FIR_HALF_SIZE-1-i] =
-				sin(2 * PI * cutoff_freq * i / 228000) / (PI * i) // sinc
-				* (.54 - .46 * cos(2*PI * (i+FIR_HALF_SIZE) / (2*FIR_HALF_SIZE))); // Hamming window
-		}
-		printf("Created low-pass FIR filter for audio channels, with cutoff at %.1i Hz\n", cutoff_freq);
-
-		audio_pos = downsample_factor;
-		audio_buffer = alloc_empty_buffer(length * channels);
-		if(audio_buffer == NULL) return -1;
-	}
-	else {
-		inf = NULL;
-	}
-
-	return 0;
-}
-
-
-// samples provided by this function are in 0..10: they need to be divided by
-// 10 after.
-int fm_mpx_get_samples(double *mpx_buffer, double *rds_buffer, float mpx, int rds, int wait) {
-	if(inf == NULL) {
-		if(rds) get_rds_samples(mpx_buffer, length);
-		return 0;
-	} else {
-		if(rds) get_rds_samples(rds_buffer, length);
-	}
-
-	for(int i=0; i<length; i++) {
-		if(audio_pos >= downsample_factor) {
-			audio_pos -= downsample_factor;
-
-			if(audio_len <= channels) {
-				for(int j=0; j<2; j++) { // one retry
-					audio_len = sf_read_double(inf, audio_buffer, length);
-					if (audio_len < 0) {
-						fprintf(stderr, "Error reading audio\n");
-						return -1;
-					}
-					if(audio_len == 0) {
-						if( sf_seek(inf, 0, SEEK_SET) < 0 ) {
-							if(wait) {
-								return 0;
-							} else {
-								fprintf(stderr, "Could not rewind in audio file, terminating\n");
-                                                        	return -1;
-							}
-						}
-					} else {
-						//apply preemphasis
-						int k;
-						int l;
-						double tmp;
-						for(k=0; k<audio_len; k+=channels) {
-							for(l=0; l<channels; l++) {
-								tmp = audio_buffer[k+l];
-								audio_buffer[k+l] = audio_buffer[k+l] - preemphasis_coefficient*last_buffer_val[l];
-								last_buffer_val[l] = tmp;
-							}
-						}
-
-						break;
-					}
-				}
-				audio_index = 0;
-			} else {
-				audio_index += channels;
-				audio_len -= channels;
-			}
-		}
-
-		// First store the current sample(s) into the FIR filter's ring buffer
-		if(channels == 0) {
-			fir_buffer_mono[fir_index] = audio_buffer[audio_index];
-		} else {
-			// In stereo operation, generate sum and difference signals
-			fir_buffer_mono[fir_index] =
-				audio_buffer[audio_index] + audio_buffer[audio_index+1];
-			fir_buffer_stereo[fir_index] =
-				audio_buffer[audio_index] - audio_buffer[audio_index+1];
-		}
-		fir_index++;
-		if(fir_index >= FIR_SIZE) fir_index = 0;
-
-		// Now apply the FIR low-pass filter
-
-		/* As the FIR filter is symmetric, we do not multiply all
-		   the coefficients independently, but two-by-two, thus reducing
-		   the total number of multiplications by a factor of two
-		 */
-		double out_mono = 0;
-		double out_stereo = 0;
-		int ifbi = fir_index; // ifbi = increasing FIR Buffer Index
-		int dfbi = fir_index; // dfbi = decreasing FIR Buffer Index
-		for(int fi=0; fi<FIR_HALF_SIZE; fi++) { // fi = Filter Index
-			dfbi--;
-			if(dfbi < 0) dfbi = FIR_SIZE-1;
-			out_mono +=
-				low_pass_fir[fi] *
-				(fir_buffer_mono[ifbi] + fir_buffer_mono[dfbi]);
-			if(channels > 1) {
-				out_stereo +=
-					low_pass_fir[fi] *
-					(fir_buffer_stereo[ifbi] + fir_buffer_stereo[dfbi]);
-			}
-			ifbi++;
-			if(ifbi >= FIR_SIZE) ifbi = 0;
-		}
-		// End of FIR filter
-
-		if (channels>1) {
-			mpx_buffer[i] =
-			((mpx-2)/2) * out_mono +
-			((mpx-2)/2) * carrier_38[phase_38] * out_stereo +
-			1 * carrier_19[phase_19];
-
-			if (rds) {
-				mpx_buffer[i] += rds_buffer[i];
-			}
-
-			phase_19++;
-			phase_38++;
-			if(phase_19 >= 12) phase_19 = 0;
-			if(phase_38 >= 6) phase_38 = 0;
-		}
-		else {
-			mpx_buffer[i] =
-			(mpx-1) * out_mono;
-
-			if (rds) {
-				mpx_buffer[i] += rds_buffer[i];
-			}
-		}
-		audio_pos++;
-	}
-
-	return 0;
-}
-
-
-int fm_mpx_close() {
-	if(sf_close(inf) ) {
-		fprintf(stderr, "Error closing audio file");
-	}
-
-	if(audio_buffer != NULL) free(audio_buffer);
-
-	return 0;
-}
diff --git a/fm_mpx.h b/fm_mpx.h
deleted file mode 100644
index 0afbe87..0000000
--- a/fm_mpx.h
+++ /dev/null
@@ -1,10 +0,0 @@
-/*
-    PiFmAdv - Advanced FM transmitter for the Raspberry Pi
-    Copyright (C) 2017 Miegl
-
-    See https://github.com/Miegl/PiFmAdv
-*/
-
-extern int fm_mpx_open(char *filename, size_t len, int cutoff_freq, int preemphasis_corner_freq, int srate, int nochan);
-extern int fm_mpx_get_samples(double *mpx_buffer, double *rds_buffer, float mpx, int rds, int wait);
-extern int fm_mpx_close();