1 files changed, 400 insertions, 0 deletions
diff --git a/trunk/codecs/codec_adpcm.c b/trunk/codecs/codec_adpcm.c
new file mode 100644
index 000000000..63a1ab1bc
--- /dev/null
+++ b/trunk/codecs/codec_adpcm.c
@@ -0,0 +1,400 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Based on frompcm.c and topcm.c from the Emiliano MIPL browser/
+ * interpreter.  See http://www.bsdtelephony.com.mx
+ *
+ * Copyright (c) 2001 - 2005 Digium, Inc.
+ * All rights reserved.
+ *
+ * Karl Sackett <krs@linux-support.net>, 2001-03-21
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! \file
+ *
+ * \brief codec_adpcm.c - translate between signed linear and Dialogic ADPCM
+ * 
+ * \ingroup codecs
+ */
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/lock.h"
+#include "asterisk/linkedlists.h"
+#include "asterisk/module.h"
+#include "asterisk/config.h"
+#include "asterisk/translate.h"
+#include "asterisk/utils.h"
+
+/* define NOT_BLI to use a faster but not bit-level identical version */
+/* #define NOT_BLI */
+
+#define BUFFER_SAMPLES   8096	/* size for the translation buffers */
+
+/* Sample frame data */
+
+#include "slin_adpcm_ex.h"
+#include "adpcm_slin_ex.h"
+
+/*
+ * Step size index shift table 
+ */
+
+static int indsft[8] = { -1, -1, -1, -1, 2, 4, 6, 8 };
+
+/*
+ * Step size table, where stpsz[i]=floor[16*(11/10)^i]
+ */
+
+static int stpsz[49] = {
+  16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73,
+  80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279,
+  307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963,
+  1060, 1166, 1282, 1411, 1552
+};
+
+/*
+ * Decoder/Encoder state
+ *   States for both encoder and decoder are synchronized
+ */
+struct adpcm_state {
+	int ssindex;
+	int signal;
+	int zero_count;
+	int next_flag;
+};
+
+/*
+ * Decode(encoded)
+ *  Decodes the encoded nibble from the adpcm file.
+ *
+ * Results:
+ *  Returns the encoded difference.
+ *
+ * Side effects:
+ *  Sets the index to the step size table for the next encode.
+ */
+
+static inline short decode(int encoded, struct adpcm_state *state)
+{
+	int diff;
+	int step;
+	int sign;
+
+	step = stpsz[state->ssindex];
+
+	sign = encoded & 0x08;
+	encoded &= 0x07;
+#ifdef NOT_BLI
+	diff = (((encoded << 1) + 1) * step) >> 3;
+#else /* BLI code */
+	diff = step >> 3;
+	if (encoded & 4)
+		diff += step;
+	if (encoded & 2)
+		diff += step >> 1;
+	if (encoded & 1)
+		diff += step >> 2;
+	if ((encoded >> 1) & step & 0x1)
+		diff++;
+#endif
+	if (sign)
+		diff = -diff;
+
+	if (state->next_flag & 0x1)
+		state->signal -= 8;
+	else if (state->next_flag & 0x2)
+		state->signal += 8;
+
+	state->signal += diff;
+
+	if (state->signal > 2047)
+		state->signal = 2047;
+	else if (state->signal < -2047)
+		state->signal = -2047;
+
+	state->next_flag = 0;
+
+#ifdef AUTO_RETURN
+	if (encoded)
+		state->zero_count = 0;
+	else if (++(state->zero_count) == 24) {
+		state->zero_count = 0;
+		if (state->signal > 0)
+			state->next_flag = 0x1;
+		else if (state->signal < 0)
+			state->next_flag = 0x2;
+	}
+#endif
+
+	state->ssindex += indsft[encoded];
+	if (state->ssindex < 0)
+		state->ssindex = 0;
+	else if (state->ssindex > 48)
+		state->ssindex = 48;
+
+	return state->signal << 4;
+}
+
+/*
+ * Adpcm
+ *  Takes a signed linear signal and encodes it as ADPCM
+ *  For more information see http://support.dialogic.com/appnotes/adpcm.pdf
+ *
+ * Results:
+ *  Foo.
+ *
+ * Side effects:
+ *  signal gets updated with each pass.
+ */
+
+static inline int adpcm(short csig, struct adpcm_state *state)
+{
+	int diff;
+	int step;
+	int encoded;
+
+	/* 
+	 * Clip csig if too large or too small
+	 */
+	csig >>= 4;
+
+	step = stpsz[state->ssindex];
+	diff = csig - state->signal;
+
+#ifdef NOT_BLI
+	if (diff < 0) {
+		encoded = (-diff << 2) / step;
+		if (encoded > 7)
+			encoded = 7;
+		encoded |= 0x08;
+	} else {
+		encoded = (diff << 2) / step;
+		if (encoded > 7)
+			encoded = 7;
+	}
+#else /* BLI code */
+	if (diff < 0) {
+		encoded = 8;
+		diff = -diff;
+	} else
+		encoded = 0;
+	if (diff >= step) {
+		encoded |= 4;
+		diff -= step;
+	}
+	step >>= 1;
+	if (diff >= step) {
+		encoded |= 2;
+		diff -= step;
+	}
+	step >>= 1;
+	if (diff >= step)
+		encoded |= 1;
+#endif /* NOT_BLI */
+
+	/* feedback to state */
+	decode(encoded, state);
+	
+	return encoded;
+}
+
+/*----------------- Asterisk-codec glue ------------*/
+
+/*! \brief Workspace for translating signed linear signals to ADPCM. */
+struct adpcm_encoder_pvt {
+	struct adpcm_state state;
+	int16_t inbuf[BUFFER_SAMPLES];	/* Unencoded signed linear values */
+};
+
+/*! \brief Workspace for translating ADPCM signals to signed linear. */
+struct adpcm_decoder_pvt {
+	struct adpcm_state state;
+};
+
+/*! \brief decode 4-bit adpcm frame data and store in output buffer */
+static int adpcmtolin_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
+{
+	struct adpcm_decoder_pvt *tmp = pvt->pvt;
+	int x = f->datalen;
+	unsigned char *src = f->data;
+	int16_t *dst = (int16_t *)pvt->outbuf + pvt->samples;
+
+	while (x--) {
+		*dst++ = decode((*src >> 4) & 0xf, &tmp->state);
+		*dst++ = decode(*src++ & 0x0f, &tmp->state);
+	}
+	pvt->samples += f->samples;
+	pvt->datalen += 2*f->samples;
+	return 0;
+}
+
+/*! \brief fill input buffer with 16-bit signed linear PCM values. */
+static int lintoadpcm_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
+{
+	struct adpcm_encoder_pvt *tmp = pvt->pvt;
+
+	memcpy(&tmp->inbuf[pvt->samples], f->data, f->datalen);
+	pvt->samples += f->samples;
+	return 0;
+}
+
+/*! \brief convert inbuf and store into frame */
+static struct ast_frame *lintoadpcm_frameout(struct ast_trans_pvt *pvt)
+{
+	struct adpcm_encoder_pvt *tmp = pvt->pvt;
+	struct ast_frame *f;
+	int i;
+	int samples = pvt->samples;	/* save original number */
+  
+	if (samples < 2)
+		return NULL;
+
+	pvt->samples &= ~1; /* atomic size is 2 samples */
+
+	for (i = 0; i < pvt->samples; i += 2) {
+		pvt->outbuf[i/2] =
+			(adpcm(tmp->inbuf[i  ], &tmp->state) << 4) |
+			(adpcm(tmp->inbuf[i+1], &tmp->state)     );
+	};
+
+	f = ast_trans_frameout(pvt, pvt->samples/2, 0);
+
+	/*
+	 * If there is a left over sample, move it to the beginning
+	 * of the input buffer.
+	 */
+
+	if (samples & 1) {	/* move the leftover sample at beginning */
+		tmp->inbuf[0] = tmp->inbuf[samples - 1];
+		pvt->samples = 1;
+	}
+	return f;
+}
+
+
+/*! \brief AdpcmToLin_Sample */
+static struct ast_frame *adpcmtolin_sample(void)
+{
+	static struct ast_frame f;
+	f.frametype = AST_FRAME_VOICE;
+	f.subclass = AST_FORMAT_ADPCM;
+	f.datalen = sizeof(adpcm_slin_ex);
+	f.samples = sizeof(adpcm_slin_ex) * 2;
+	f.mallocd = 0;
+	f.offset = 0;
+	f.src = __PRETTY_FUNCTION__;
+	f.data = adpcm_slin_ex;
+	return &f;
+}
+
+/*! \brief LinToAdpcm_Sample */
+static struct ast_frame *lintoadpcm_sample(void)
+{
+	static struct ast_frame f;
+	f.frametype = AST_FRAME_VOICE;
+	f.subclass = AST_FORMAT_SLINEAR;
+	f.datalen = sizeof(slin_adpcm_ex);
+	/* Assume 8000 Hz */
+	f.samples = sizeof(slin_adpcm_ex) / 2;
+	f.mallocd = 0;
+	f.offset = 0;
+	f.src = __PRETTY_FUNCTION__;
+	f.data = slin_adpcm_ex;
+	return &f;
+}
+
+static struct ast_translator adpcmtolin = {
+	.name = "adpcmtolin",
+	.srcfmt = AST_FORMAT_ADPCM,
+	.dstfmt = AST_FORMAT_SLINEAR,
+	.framein = adpcmtolin_framein,
+	.sample = adpcmtolin_sample,
+	.desc_size = sizeof(struct adpcm_decoder_pvt),
+	.buffer_samples = BUFFER_SAMPLES,
+	.buf_size = BUFFER_SAMPLES * 2,
+	.plc_samples = 160,
+};
+
+static struct ast_translator lintoadpcm = {
+	.name = "lintoadpcm",
+	.srcfmt = AST_FORMAT_SLINEAR,
+	.dstfmt = AST_FORMAT_ADPCM,
+	.framein = lintoadpcm_framein,
+	.frameout = lintoadpcm_frameout,
+	.sample = lintoadpcm_sample,
+	.desc_size = sizeof (struct adpcm_encoder_pvt),
+	.buffer_samples = BUFFER_SAMPLES,
+	.buf_size = BUFFER_SAMPLES/ 2,	/* 2 samples per byte */
+};
+
+static int parse_config(int reload)
+{
+	struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
+	struct ast_config *cfg = ast_config_load("codecs.conf", config_flags);
+	struct ast_variable *var;
+	if (cfg == NULL)
+		return 0;
+	if (cfg == CONFIG_STATUS_FILEUNCHANGED)
+		return 0;
+	for (var = ast_variable_browse(cfg, "plc"); var ; var = var->next) {
+		if (!strcasecmp(var->name, "genericplc")) {
+			adpcmtolin.useplc = ast_true(var->value) ? 1 : 0;
+			ast_verb(3, "codec_adpcm: %susing generic PLC\n", adpcmtolin.useplc ? "" : "not ");
+		}
+	}
+	ast_config_destroy(cfg);
+	return 0;
+}
+
+/*! \brief standard module glue */
+static int reload(void)
+{
+	if (parse_config(1))
+		return AST_MODULE_LOAD_DECLINE;
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+static int unload_module(void)
+{
+	int res;
+
+	res = ast_unregister_translator(&lintoadpcm);
+	res |= ast_unregister_translator(&adpcmtolin);
+
+	return res;
+}
+
+static int load_module(void)
+{
+	int res;
+
+	if (parse_config(0))
+		return AST_MODULE_LOAD_DECLINE;
+	res = ast_register_translator(&adpcmtolin);
+	if (!res)
+		res = ast_register_translator(&lintoadpcm);
+	else
+		ast_unregister_translator(&adpcmtolin);
+	if (res)
+		return AST_MODULE_LOAD_FAILURE;
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "Adaptive Differential PCM Coder/Decoder",
+		.load = load_module,
+		.unload = unload_module,
+		.reload = reload,
+	       );