diff --git a/src/Makefile.am b/src/Makefile.am
index 4a6689e..9383b7d 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -4,5 +4,5 @@
 
 bin_PROGRAMS = gapk
 gapk_SOURCES =	main.c	\
-		formats.c fmt_gsm.c \
+		formats.c fmt_gsm.c fmt_hr_ref.c \
 		codecs.c codec_pcm.c codec_hr.c codec_fr.c codec_efr.c
diff --git a/src/fmt_hr_ref.c b/src/fmt_hr_ref.c
new file mode 100644
index 0000000..7a96d3e
--- /dev/null
+++ b/src/fmt_hr_ref.c
@@ -0,0 +1,205 @@
+/* 3GPP Reference HR vocoder file formats 
+ *
+ * See http://ftp.3gpp.org/Specs/2001-06/Ph2/06_series/0606-421/0606_421.zip
+ */
+
+/*
+ * This file is part of gapk (GSM Audio Pocket Knife).
+ *
+ * gapk 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.
+ *
+ * gapk 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 gapk.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gapk/codecs.h>
+#include <gapk/formats.h>
+#include <gapk/utils.h>
+
+
+static const int params_unvoiced[] = {
+	5,	/* R0 */
+	11,	/* k1Tok3 */
+	9,	/* k4Tok6 */
+	8,	/* k7Tok10 */
+	1,	/* softInterpolation */
+	2,	/* voicingDecision */
+	7,	/* code1_1 */
+	7,	/* code2_1 */
+	5,	/* gsp0_1 */
+	7,	/* code1_2 */
+	7,	/* code2_2 */
+	5,	/* gsp0_2 */
+	7,	/* code1_3 */
+	7,	/* code2_3 */
+	5,	/* gsp0_3 */
+	7,	/* code1_4 */
+	7,	/* code2_4 */
+	5,	/* gsp0_4 */
+};
+
+static const int params_voiced[] = {
+	5,	/* R0 */
+	11,	/* k1Tok3 */
+	9,	/* k4Tok6 */
+	8,	/* k7Tok10 */
+	1,	/* softInterpolation */
+	2,	/* voicingDecision */
+	8,	/* frameLag */
+	9,	/* code_1 */
+	5,	/* gsp0_1 */
+	4,	/* deltaLag_2 */
+	9,	/* code_2 */
+	5,	/* gsp0_2 */
+	4,	/* deltaLag_3 */
+	9,	/* code_3 */
+	5,	/* gsp0_3 */
+	4,	/* deltaLag_4 */
+	9,	/* code_4 */
+	5,	/* gsp0_4 */
+};
+
+
+static int
+hr_ref_from_canon(uint16_t *hr_ref, const uint8_t *canon)
+{
+	int i, j, voiced;
+	const int *params;
+
+	voiced = (msb_get_bit(canon, 34) << 1) | msb_get_bit(canon, 35);
+	params = voiced ? &params_voiced[0] : &params_unvoiced[0];
+
+	for (i=0,j=0; i<18; i++)
+	{
+		uint16_t w;
+		int l, k;
+
+		l = params[i];
+
+		w = 0;
+		for (k=0; k<l; k++)
+			w = (w << 1) | msb_get_bit(canon, j+k);
+		hr_ref[i] = w;
+
+		j += l;
+	}
+
+	return 0;
+}
+
+static int
+hr_ref_to_canon(uint8_t *canon, const uint16_t *hr_ref)
+{
+	int i, j, voiced;
+	const int *params;
+
+	voiced = hr_ref[5]; /* voicingDecision */
+	params = voiced ? &params_voiced[0] : &params_unvoiced[0];
+
+	for (i=0,j=0; i<18; i++)
+	{
+		uint16_t w;
+		int l, k;
+
+		l = params[i];
+
+		w = hr_ref[i];
+		for (k=0; k<l; k++)
+			msb_put_bit(canon, j+k, w & (1<<(l-k-1)));
+
+		j += l;
+	}
+
+	return 0;
+}
+
+static int
+hr_ref_dec_from_canon(uint8_t *dst, const uint8_t *src)
+{
+	uint16_t *hr_ref = (uint16_t *)dst;
+	int rv;
+
+	rv = hr_ref_from_canon(hr_ref, src);
+	if (rv)
+		return rv;
+
+	hr_ref[18] = 0;		/* BFI : 1 bit */
+	hr_ref[19] = 0;		/* UFI : 1 bit */
+	hr_ref[20] = 0;		/* SID : 2 bit */
+	hr_ref[21] = 0;		/* TAF : 1 bit */
+
+	return 0;
+}
+
+static int
+hr_ref_dec_to_canon(uint8_t *dst, const uint8_t *src)
+{
+	const uint16_t *hr_ref = (const uint16_t *)src;
+	int rv;
+
+	rv = hr_ref_to_canon(dst, hr_ref);
+	if (rv)
+		return rv;
+
+	return 0;
+}
+
+static int
+hr_ref_enc_from_canon(uint8_t *dst, const uint8_t *src)
+{
+	uint16_t *hr_ref = (uint16_t *)dst;
+	int rv;
+
+	rv = hr_ref_from_canon(hr_ref, src);
+	if (rv)
+		return rv;
+
+	hr_ref[18] = 0;		/* SP  : 1 bit */
+	hr_ref[19] = 0;		/* VAD : 1 bit */
+
+	return 0;
+}
+
+static int
+hr_ref_enc_to_canon(uint8_t *dst, const uint8_t *src)
+{
+	const uint16_t *hr_ref = (const uint16_t *)src;
+	int rv;
+
+	rv = hr_ref_to_canon(dst, hr_ref);
+	if (rv)
+		return rv;
+
+	return 0;
+}
+
+
+const struct format_desc fmt_hr_ref_dec = {
+	.type			= FMT_HR_REF_DEC,
+	.codec_type		= CODEC_HR,
+	.name			= "hr-ref-dec",
+	.description		= "3GPP HR Reference decoder code parameters file format",
+
+	.frame_len		= 22 * sizeof(uint16_t),
+	.conv_from_canon	= hr_ref_dec_from_canon,
+	.conv_to_canon		= hr_ref_dec_to_canon,
+};
+
+const struct format_desc fmt_hr_ref_enc = {
+	.type			= FMT_HR_REF_ENC,
+	.codec_type		= CODEC_HR,
+	.name			= "hr-ref-enc",
+	.description		= "3GPP HR Reference encoder code parameters file format",
+
+	.frame_len		= 20 * sizeof(uint16_t),
+	.conv_from_canon	= hr_ref_enc_from_canon,
+	.conv_to_canon		= hr_ref_enc_to_canon,
+};
diff --git a/src/formats.c b/src/formats.c
index 5c91a52..1125598 100644
--- a/src/formats.c
+++ b/src/formats.c
@@ -23,10 +23,14 @@
 
 /* Extern format descriptors */
 extern const struct format_desc fmt_gsm;
+extern const struct format_desc fmt_hr_ref_dec;
+extern const struct format_desc fmt_hr_ref_enc;
 
 static const struct format_desc *supported_formats[_FMT_MAX] = {
 	[FMT_INVALID]		= NULL,
 	[FMT_GSM]		= &fmt_gsm,
+	[FMT_HR_REF_DEC]	= &fmt_hr_ref_dec,
+	[FMT_HR_REF_ENC]	= &fmt_hr_ref_enc,
 };