Restructure: Move sample rate conversion from common code to 'libsamplerate'

6 files changed, 4 insertions, 179 deletions

diff --git a/src/common/Makefile.am b/src/common/Makefile.am
index 7a59d64..6f8ae93 100644
--- a/src/common/Makefile.am
+++ b/src/common/Makefile.am
@@ -11,7 +11,6 @@ libcommon_a_SOURCES = \
 	goertzel.c \
 	jitter.c \
 	dtmf.c \
-	samplerate.c \
 	emphasis.c \
 	compandor.c \
 	fft.c \
diff --git a/src/common/emphasis.h b/src/common/emphasis.h
index 0e91509..43d54e6 100644
--- a/src/common/emphasis.h
+++ b/src/common/emphasis.h
@@ -1,3 +1,5 @@
+#include "../libfilter/iir_filter.h"
+
 typedef struct emphasis {
 	struct {
 		iir_filter_t lp;
diff --git a/src/common/mncc_console.c b/src/common/mncc_console.c
index 1e65d04..fc779f4 100644
--- a/src/common/mncc_console.c
+++ b/src/common/mncc_console.c
@@ -25,7 +25,7 @@
 #include <errno.h>
 #include <sys/time.h>
 #include "sample.h"
-#include "samplerate.h"
+#include "../libsamplerate/samplerate.h"
 #include "jitter.h"
 #include "debug.h"
 #include "testton.h"
diff --git a/src/common/samplerate.c b/src/common/samplerate.c
deleted file mode 100644
index db6b278..0000000
--- a/src/common/samplerate.c
+++ /dev/null
@@ -1,157 +0,0 @@
-/* Sample rate conversion
- *
- * (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
- * All Rights Reserved
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <stdio.h>
-#include <stdint.h>
-#include <errno.h>
-#include <string.h>
-#include <stdlib.h>
-#include "sample.h"
-#include "samplerate.h"
-
-int init_samplerate(samplerate_t *state, double low_samplerate, double high_samplerate, double filter_cutoff)
-{
-	memset(state, 0, sizeof(*state));
-	state->factor = high_samplerate / low_samplerate;
-	if (state->factor < 1.0) {
-		fprintf(stderr, "Software error: Low sample rate must be lower than high sample rate, aborting!\n");
-		abort();
-	}
-
-	iir_lowpass_init(&state->up.lp, filter_cutoff, high_samplerate, 2);
-	iir_lowpass_init(&state->down.lp, filter_cutoff, high_samplerate, 2);
-
-	return 0;
-}
-
-/* convert high sample rate to low sample rate */
-int samplerate_downsample(samplerate_t *state, sample_t *samples, int input_num)
-{
-	int output_num = 0, i, idx;
-	double factor = state->factor, in_index, diff;
-	sample_t output[(int)((double)input_num / factor + 0.5) + 10]; /* add some safety */
-	sample_t last_sample;
-
-	/* filter down */
-	iir_process(&state->down.lp, samples, input_num);
-
-	/* get last sample for interpolation */
-	last_sample = state->down.last_sample;
-
-	/* resample filtered result */
-	in_index = state->down.in_index;
-
-	for (i = 0; ; i++) {
-		/* convert index to int */
-		idx = (int)in_index;
-		/* if index is outside input sample range, we are done */
-		if (idx >= input_num)
-			break;
-		/* linear interpolation */
-		diff = in_index - (double)idx;
-		if (idx)
-			output[i] = samples[idx - 1] * (1.0 - diff) + samples[idx] * diff;
-		else
-			output[i] = last_sample * (1.0 - diff) + samples[idx] * diff;
-		/* count output number */
-		output_num++;
-		/* increment input index */
-		in_index += factor;
-	}
-
-	/* store last sample for interpolation */
-	if (input_num)
-		state->down.last_sample = samples[input_num - 1];
-
-	/* remove number of input samples from index */
-	in_index -= (double)input_num;
-	/* in_index cannot be negative, excpet due to rounding error, so... */
-	if ((int)in_index < 0)
-		in_index = 0.0;
-
-	state->down.in_index = in_index;
-
-	/* copy samples */
-	for (i = 0; i < output_num; i++)
-		*samples++ = output[i];
-
-	return output_num;
-}
-
-/* convert low sample rate to high sample rate */
-int samplerate_upsample(samplerate_t *state, sample_t *input, int input_num, sample_t *output)
-{
-	int output_num = 0, i, idx;
-	double factor = 1.0 / state->factor, in_index, diff;
-	sample_t buff[(int)((double)input_num / factor + 0.5) + 10]; /* add some safety */
-	sample_t *samples, last_sample;
-
-	/* get last sample for interpolation */
-	last_sample = state->up.last_sample;
-
-	if (input == output)
-		samples = buff;
-	else
-		samples = output;
-
-	/* resample input */
-	in_index = state->up.in_index;
-
-	for (i = 0; ; i++) {
-		/* convert index to int */
-		idx = (int)in_index;
-		/* if index is outside input sample range, we are done */
-		if (idx >= input_num)
-			break;
-		/* linear interpolation */
-		diff = in_index - (double)idx;
-		if (idx)
-			samples[i] = input[idx - 1] * (1.0 - diff) + input[idx] * diff;
-		else
-			samples[i] = last_sample * (1.0 - diff) + input[idx] * diff;
-		/* count output number */
-		output_num++;
-		/* increment input index */
-		in_index += factor;
-	}
-
-	/* store last sample for interpolation */
-	if (input_num)
-		state->up.last_sample = input[input_num - 1];
-
-	/* remove number of input samples from index */
-	in_index -= (double)input_num;
-	/* in_index cannot be negative, excpet due to rounding error, so... */
-	if ((int)in_index < 0)
-		in_index = 0.0;
-
-	state->up.in_index = in_index;
-
-	/* filter up */
-	iir_process(&state->up.lp, samples, output_num);
-
-	if (input == output) {
-		/* copy samples */
-		for (i = 0; i < output_num; i++)
-			*output++ = samples[i];
-	}
-
-	return output_num;
-}
-
diff --git a/src/common/samplerate.h b/src/common/samplerate.h
deleted file mode 100644
index 8f8ea87..0000000
--- a/src/common/samplerate.h
+++ /dev/null
@@ -1,19 +0,0 @@
-#include "../libfilter/iir_filter.h"
-
-typedef struct samplerate {
-	double factor;
-	struct {
-		iir_filter_t lp;
-		sample_t last_sample;
-		double in_index;
-	} down;
-	struct {
-		iir_filter_t lp;
-		sample_t last_sample;
-		double in_index;
-	} up;
-} samplerate_t;
-
-int init_samplerate(samplerate_t *state, double low_samplerate, double high_samplerate, double filter_cutoff);
-int samplerate_downsample(samplerate_t *state, sample_t *samples, int input_num);
-int samplerate_upsample(samplerate_t *state, sample_t *input, int input_num, sample_t *output);
diff --git a/src/common/sender.h b/src/common/sender.h
index 4ca728f..c222fda 100644
--- a/src/common/sender.h
+++ b/src/common/sender.h
@@ -3,7 +3,7 @@
 #include "sdr.h"
 #endif
 #include "wave.h"
-#include "samplerate.h"
+#include "../libsamplerate/samplerate.h"
 #include "jitter.h"
 #include "emphasis.h"
 #include "display.h"