--- a/.hgignore	Sun Nov 20 01:34:57 2022 +0000
+++ b/.hgignore	Sun Nov 20 01:54:10 2022 +0000
@@ -6,3 +6,4 @@
 ^dev/gsm0611-silence-fr\.out$
 
 ^frtest/gsmfr-decode$
+^frtest/gsmfr-encode$

--- a/frtest/Makefile	Sun Nov 20 01:34:57 2022 +0000
+++ b/frtest/Makefile	Sun Nov 20 01:54:10 2022 +0000
@@ -1,12 +1,17 @@
 CC=	gcc
 CFLAGS=	-O2
-PROGS=	gsmfr-decode
-LIBS=	../libtest/libtest.a ../libgsmfrp/libgsmfrp.a
+PROGS=	gsmfr-decode gsmfr-encode
+LIBPP=	../libgsmfrp/libgsmfrp.a
+LIBTEST=../libtest/libtest.a
+LIBDEC=	${LIBTEST} ${LIBPP}
 
 all:	${PROGS}
 
-gsmfr-decode:	decode.o ${LIBS}
-	${CC} ${CFLAGS} -o $@ decode.o ${LIBS} -lgsm
+gsmfr-decode:	decode.o ${LIBDEC}
+	${CC} ${CFLAGS} -o $@ decode.o ${LIBDEC} -lgsm
+
+gsmfr-encode:	encode.o ${LIBTEST}
+	${CC} ${CFLAGS} -o $@ encode.o ${LIBTEST} -lgsm
 
 clean:
 	rm -f *.o *.out ${PROGS}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/frtest/encode.c	Sun Nov 20 01:54:10 2022 +0000
@@ -0,0 +1,53 @@
+/*
+ * This file is the main module for gsmfr-encode utility.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <gsm.h>
+#include "../libtest/wavreader.h"
+#include "../libtest/wavrdhelp.h"
+
+main(argc, argv)
+	char **argv;
+{
+	void *wav;
+	FILE *binf;
+	gsm enc_state;
+	int16_t pcm[160];
+	uint8_t frame[33];
+	int rc;
+
+	if (argc != 3) {
+		fprintf(stderr, "usage: %s input.wav output.gsm\n", argv[0]);
+		exit(1);
+	}
+	wav = wav_read_open(argv[1]);
+	if (!wav) {
+		perror(argv[1]);
+		exit(1);
+	}
+	rc = wavrd_check_header(wav, argv[1]);
+	if (rc < 0)
+		exit(1);	/* error msg already printed */
+	binf = fopen(argv[2], "w");
+	if (!binf) {
+		perror(argv[2]);
+		exit(1);
+	}
+	enc_state = gsm_create();
+	if (!enc_state) {
+		fprintf(stderr, "gsm_create() failed!\n");
+		exit(1);
+	}
+	for (;;) {
+		rc = wavrd_get_pcm_block(wav, pcm);
+		if (!rc)
+			break;
+		gsm_encode(enc_state, pcm, frame);
+		fwrite(frame, 1, sizeof frame, binf);
+	}
+	fclose(binf);
+	exit(0);
+}