--- a/.hgignore	Wed Apr 03 19:10:09 2024 +0000
+++ b/.hgignore	Wed Apr 03 19:41:45 2024 +0000
@@ -3,3 +3,4 @@
 \.[oa]$
 
 ^amrdiff/amrdiff$
+^amrdiff/readone-amr$

--- a/amrdiff/Makefile	Wed Apr 03 19:10:09 2024 +0000
+++ b/amrdiff/Makefile	Wed Apr 03 19:41:45 2024 +0000
@@ -1,12 +1,17 @@
 CC=	gcc
 CFLAGS=	-O2
-PROG=	amrdiff
-OBJS=	amrdiff.o etsi-bit-rd.o
+PROGS=	amrdiff readone-amr
+
+AMRDIFF_OBJS=	amrdiff.o etsi-bit-rd.o
+RD_AMR_OBJS=	etsi-bit-rd.o readone-amr.o readone-common.o
 
-all:	${PROG}
+all:	${PROGS}
 
-${PROG}:	${OBJS}
-	${CC} ${CFLAGS} -o $@ ${OBJS}
+amrdiff:	${AMRDIFF_OBJS}
+	${CC} ${CFLAGS} -o $@ ${AMRDIFF_OBJS}
+
+readone-amr:	${RD_AMR_OBJS}
+	${CC} ${CFLAGS} -o $@ ${RD_AMR_OBJS}
 
 clean:
-	rm -f *.o ${PROG}
+	rm -f *.o ${PROGS}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/amrdiff/readone-amr.c	Wed Apr 03 19:41:45 2024 +0000
@@ -0,0 +1,50 @@
+/*
+ * This program reads a single frame (the first one) from an AMR *.cod file,
+ * enforces that this frame is MR122 speech, and emits the frame of 244 bits
+ * as comma-separated ASCII.  The intent is to extract the DHF in a form
+ * convenient for inclusion in amrdiff source.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include "amr_defs.h"
+
+main(argc, argv)
+	char **argv;
+{
+	char *filename;
+	int bigend, rc;
+	FILE *inf;
+	uint8_t amr_bits[COD_FORMAT_NWORDS];
+
+	if (argc != 3) {
+usage:		fprintf(stderr, "usage: %s amr-cod-file be|le\n", argv[0]);
+		exit(1);
+	}
+	filename = argv[1];
+	if (!strcmp(argv[2], "be"))
+		bigend = 1;
+	else if (!strcmp(argv[2], "le"))
+		bigend = 0;
+	else
+		goto usage;
+	inf = fopen(filename, "r");
+	if (!inf) {
+		perror(filename);
+		exit(1);
+	}
+	rc = read_etsi_bits(inf, bigend, amr_bits, COD_FORMAT_NWORDS, filename);
+	if (!rc) {
+		fprintf(stderr, "error: %s is empty\n", filename);
+		exit(1);
+	}
+	if (amr_bits[0] != TX_SPEECH_GOOD || amr_bits[245] != MR122) {
+		fprintf(stderr, "error: frame type is wrong\n");
+		exit(1);
+	}
+	emit_frame244(amr_bits + 1);
+	exit(0);
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/amrdiff/readone-common.c	Wed Apr 03 19:41:45 2024 +0000
@@ -0,0 +1,21 @@
+/*
+ * The function in this module is common between readone-amr and readone-efr.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+emit_frame244(bits)
+	uint8_t *bits;
+{
+	unsigned n;
+
+	for (n = 0; n < 244; n++) {
+		printf("%u,", bits[n]);
+		if (n % 40 == 39 || n == 243)
+			putchar('\n');
+	}
+}