1 files changed, 354 insertions, 0 deletions
diff --git a/modules/ilbc/ilbc.c b/modules/ilbc/ilbc.c
new file mode 100644
index 0000000..549be4d
--- /dev/null
+++ b/modules/ilbc/ilbc.c
@@ -0,0 +1,354 @@
+/**
+ * @file ilbc.c  Internet Low Bit Rate Codec (iLBC) audio codec
+ *
+ * Copyright (C) 2010 Creytiv.com
+ */
+#include <re.h>
+#include <baresip.h>
+#include <iLBC_define.h>
+#include <iLBC_decode.h>
+#include <iLBC_encode.h>
+
+
+/*
+ * This module implements the iLBC audio codec as defined in:
+ *
+ *     RFC 3951  Internet Low Bit Rate Codec (iLBC)
+ *     RFC 3952  RTP Payload Format for iLBC Speech
+ *
+ * The iLBC source code is not included here, but can be downloaded from
+ * http://ilbcfreeware.org/
+ *
+ * You can also use the source distributed by the Freeswitch project,
+ * see www.freeswitch.org, and then freeswitch/libs/codec/ilbc.
+ * Or you can look in the asterisk source code ...
+ *
+ *   mode=20  15.20 kbit/s  160samp  38bytes
+ *   mode=30  13.33 kbit/s  240samp  50bytes
+ */
+
+enum {
+	DEFAULT_MODE = 20, /* 20ms or 30ms */
+	USE_ENHANCER = 1
+};
+
+struct auenc_state {
+	iLBC_Enc_Inst_t enc;
+	int mode;
+	uint32_t enc_bytes;
+};
+
+struct audec_state {
+	iLBC_Dec_Inst_t dec;
+	int mode;
+	uint32_t nsamp;
+	size_t dec_bytes;
+};
+
+
+static char ilbc_fmtp[32];
+
+
+static void set_encoder_mode(struct auenc_state *st, int mode)
+{
+	if (st->mode == mode)
+		return;
+
+	info("ilbc: set iLBC encoder mode %dms\n", mode);
+
+	st->mode = mode;
+
+	switch (mode) {
+
+	case 20:
+		st->enc_bytes = NO_OF_BYTES_20MS;
+		break;
+
+	case 30:
+		st->enc_bytes = NO_OF_BYTES_30MS;
+		break;
+
+	default:
+		warning("ilbc: unknown encoder mode %d\n", mode);
+		return;
+	}
+
+	st->enc_bytes = initEncode(&st->enc, mode);
+}
+
+
+static void set_decoder_mode(struct audec_state *st, int mode)
+{
+	if (st->mode == mode)
+		return;
+
+	info("ilbc: set iLBC decoder mode %dms\n", mode);
+
+	st->mode = mode;
+
+	switch (mode) {
+
+	case 20:
+		st->nsamp = BLOCKL_20MS;
+		break;
+
+	case 30:
+		st->nsamp = BLOCKL_30MS;
+		break;
+
+	default:
+		warning("ilbc: unknown decoder mode %d\n", mode);
+		return;
+	}
+
+	st->nsamp = initDecode(&st->dec, mode, USE_ENHANCER);
+}
+
+
+static void encoder_fmtp_decode(struct auenc_state *st, const char *fmtp)
+{
+	struct pl mode;
+
+	if (!fmtp)
+		return;
+
+	if (re_regex(fmtp, strlen(fmtp), "mode=[0-9]+", &mode))
+		return;
+
+	set_encoder_mode(st, pl_u32(&mode));
+}
+
+
+static void decoder_fmtp_decode(struct audec_state *st, const char *fmtp)
+{
+	struct pl mode;
+
+	if (!fmtp)
+		return;
+
+	if (re_regex(fmtp, strlen(fmtp), "mode=[0-9]+", &mode))
+		return;
+
+	set_decoder_mode(st, pl_u32(&mode));
+}
+
+
+static void encode_destructor(void *arg)
+{
+	struct auenc_state *st = arg;
+	(void)st;
+}
+
+
+static void decode_destructor(void *arg)
+{
+	struct audec_state *st = arg;
+	(void)st;
+}
+
+
+static int check_ptime(const struct auenc_param *prm)
+{
+	if (!prm)
+		return 0;
+
+	switch (prm->ptime) {
+
+	case 20:
+	case 30:
+		return 0;
+
+	default:
+		warning("ilbc: invalid ptime %u ms\n", prm->ptime);
+		return EINVAL;
+	}
+}
+
+
+static int encode_update(struct auenc_state **aesp, const struct aucodec *ac,
+			 struct auenc_param *prm, const char *fmtp)
+{
+	struct auenc_state *st;
+	int err = 0;
+
+	if (!aesp || !ac || !prm)
+		return EINVAL;
+	if (check_ptime(prm))
+		return EINVAL;
+	if (*aesp)
+		return 0;
+
+	st = mem_zalloc(sizeof(*st), encode_destructor);
+	if (!st)
+		return ENOMEM;
+
+	set_encoder_mode(st, DEFAULT_MODE);
+
+	if (str_isset(fmtp))
+		encoder_fmtp_decode(st, fmtp);
+
+	/* update parameters after SDP was decoded */
+	if (prm) {
+		prm->ptime = st->mode;
+	}
+
+	if (err)
+		mem_deref(st);
+	else
+		*aesp = st;
+
+	return err;
+}
+
+
+static int decode_update(struct audec_state **adsp,
+			 const struct aucodec *ac, const char *fmtp)
+{
+	struct audec_state *st;
+	int err = 0;
+	(void)fmtp;
+
+	if (!adsp || !ac)
+		return EINVAL;
+	if (*adsp)
+		return 0;
+
+	st = mem_zalloc(sizeof(*st), decode_destructor);
+	if (!st)
+		return ENOMEM;
+
+	set_decoder_mode(st, DEFAULT_MODE);
+
+	if (str_isset(fmtp))
+		decoder_fmtp_decode(st, fmtp);
+
+	if (err)
+		mem_deref(st);
+	else
+		*adsp = st;
+
+	return err;
+}
+
+
+static int encode(struct auenc_state *st, uint8_t *buf,
+		  size_t *len, const int16_t *sampv, size_t sampc)
+{
+	float float_buf[sampc];
+	uint32_t i;
+
+	/* Make sure there is enough space */
+	if (*len < st->enc_bytes) {
+		warning("ilbc: encode: buffer is too small (%u bytes)\n",
+			*len);
+		return ENOMEM;
+	}
+
+	/* Convert from 16-bit samples to float */
+	for (i=0; i<sampc; i++) {
+		const int16_t v = sampv[i];
+		float_buf[i] = (float)v;
+	}
+
+	iLBC_encode(buf,            /* (o) encoded data bits iLBC */
+		    float_buf,      /* (o) speech vector to encode */
+		    &st->enc);      /* (i/o) the general encoder state */
+
+	*len = st->enc_bytes;
+
+	return 0;
+}
+
+
+static int do_dec(struct audec_state *st, int16_t *sampv, size_t *sampc,
+		  const uint8_t *buf, size_t len)
+{
+	float float_buf[st->nsamp];
+	const int mode = len ? 1 : 0;
+	uint32_t i;
+
+	/* Make sure there is enough space in the buffer */
+	if (*sampc < st->nsamp)
+		return ENOMEM;
+
+	iLBC_decode(float_buf,      /* (o) decoded signal block */
+		    (uint8_t *)buf, /* (i) encoded signal bits */
+		    &st->dec,       /* (i/o) the decoder state structure */
+		    mode);          /* (i) 0: bad packet, PLC, 1: normal */
+
+	/* Convert from float to 16-bit samples */
+	for (i=0; i<st->nsamp; i++) {
+		sampv[i] = (int16_t)float_buf[i];
+	}
+
+	*sampc = st->nsamp;
+
+	return 0;
+}
+
+
+static int decode(struct audec_state *st, int16_t *sampv,
+		  size_t *sampc, const uint8_t *buf, size_t len)
+{
+	/* Try to detect mode */
+	if (st->dec_bytes != len) {
+
+		st->dec_bytes = len;
+
+		switch (st->dec_bytes) {
+
+		case NO_OF_BYTES_20MS:
+			set_decoder_mode(st, 20);
+			break;
+
+		case NO_OF_BYTES_30MS:
+			set_decoder_mode(st, 30);
+			break;
+
+		default:
+			warning("ilbc: decode: expect %u, got %u\n",
+				st->dec_bytes, len);
+			return EINVAL;
+		}
+	}
+
+	return do_dec(st, sampv, sampc, buf, len);
+}
+
+
+static int pkloss(struct audec_state *st, int16_t *sampv, size_t *sampc)
+{
+	return do_dec(st, sampv, sampc, NULL, 0);
+}
+
+
+static struct aucodec ilbc = {
+	LE_INIT, 0, "iLBC", 8000, 1, ilbc_fmtp,
+	encode_update, encode, decode_update, decode, pkloss, 0, 0
+};
+
+
+static int module_init(void)
+{
+	(void)re_snprintf(ilbc_fmtp, sizeof(ilbc_fmtp),
+			  "mode=%d", DEFAULT_MODE);
+
+	aucodec_register(&ilbc);
+	return 0;
+}
+
+
+static int module_close(void)
+{
+	aucodec_unregister(&ilbc);
+	return 0;
+}
+
+
+/** Module exports */
+EXPORT_SYM const struct mod_export DECL_EXPORTS(ilbc) = {
+	"ilbc",
+	"codec",
+	module_init,
+	module_close
+};