asterisk/funcs/func_speex.c

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2008, Digium, Inc.
 *
 * Brian Degenhardt <bmd@digium.com>
 * Brett Bryant <bbryant@digium.com> 
 *
 * 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 Noise reduction and automatic gain control (AGC)
 *
 * \author Brian Degenhardt <bmd@digium.com> 
 * \author Brett Bryant <bbryant@digium.com> 
 *
 * \ingroup functions
 *
 * \extref The Speex library - http://www.speex.org
 */

/*** MODULEINFO
	<depend>speex</depend>
	<depend>speex_preprocess</depend>
	<use>speexdsp</use>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

#include <speex/speex_preprocess.h>
#include "asterisk/module.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/utils.h"
#include "asterisk/audiohook.h"

#define DEFAULT_AGC_LEVEL 8000.0

struct speex_direction_info {
	SpeexPreprocessState *state;	/*!< speex preprocess state object */
	int agc;						/*!< audio gain control is enabled or not */
	int denoise;					/*!< denoise is enabled or not */
	int samples;					/*!< n of 8Khz samples in last frame */
	float agclevel;					/*!< audio gain control level [1.0 - 32768.0] */
};

struct speex_info {
	struct ast_audiohook audiohook;
	struct speex_direction_info *tx, *rx;
};

static void destroy_callback(void *data) 
{
	struct speex_info *si = data;

	ast_audiohook_destroy(&si->audiohook);

	if (si->rx && si->rx->state) {
		speex_preprocess_state_destroy(si->rx->state);
	}

	if (si->tx && si->tx->state) {
		speex_preprocess_state_destroy(si->tx->state);
	}

	if (si->rx) {
		ast_free(si->rx);
	}

	if (si->tx) {
		ast_free(si->tx);
	}

	ast_free(data);
};

static const struct ast_datastore_info speex_datastore = {
	.type = "speex",
	.destroy = destroy_callback
};

static int speex_callback(struct ast_audiohook *audiohook, struct ast_channel *chan, struct ast_frame *frame, enum ast_audiohook_direction direction)
{
	struct ast_datastore *datastore = NULL;
	struct speex_direction_info *sdi = NULL;
	struct speex_info *si = NULL;

	/* If the audiohook is stopping it means the channel is shutting down.... but we let the datastore destroy take care of it */
	if (audiohook->status == AST_AUDIOHOOK_STATUS_DONE || frame->frametype != AST_FRAME_VOICE) {
		return 0;
	}
	
	ast_channel_lock(chan);
	if (!(datastore = ast_channel_datastore_find(chan, &speex_datastore, NULL))) {
		ast_channel_unlock(chan);
		return 0;
	}
	ast_channel_unlock(chan);

	si = datastore->data;

	sdi = (direction == AST_AUDIOHOOK_DIRECTION_READ) ? si->rx : si->tx;

	if (!sdi) {
		return 0;
	}

	if (sdi->samples != frame->samples) {
		if (sdi->state) {
			speex_preprocess_state_destroy(sdi->state);
		}

		if (!(sdi->state = speex_preprocess_state_init((sdi->samples = frame->samples), 8000))) {
			return -1;
		}
		
		speex_preprocess_ctl(sdi->state, SPEEX_PREPROCESS_SET_AGC, &sdi->agc);

		if (sdi->agc) {
			speex_preprocess_ctl(sdi->state, SPEEX_PREPROCESS_SET_AGC_LEVEL, &sdi->agclevel);
		}

		speex_preprocess_ctl(sdi->state, SPEEX_PREPROCESS_SET_DENOISE, &sdi->denoise);
	}

	speex_preprocess(sdi->state, frame->data.ptr, NULL);

	return 0;
}

static int speex_write(struct ast_channel *chan, const char *cmd, char *data, const char *value)
{
	struct ast_datastore *datastore = NULL;
	struct speex_info *si = NULL;
	struct speex_direction_info **sdi = NULL;
	int is_new = 0;

	ast_channel_lock(chan);
	if (!(datastore = ast_channel_datastore_find(chan, &speex_datastore, NULL))) {
		ast_channel_unlock(chan);

		if (!(datastore = ast_datastore_alloc(&speex_datastore, NULL))) {
			return 0;
		}

		if (!(si = ast_calloc(1, sizeof(*si)))) {
			ast_datastore_free(datastore);
			return 0;
		}

		ast_audiohook_init(&si->audiohook, AST_AUDIOHOOK_TYPE_MANIPULATE, "speex");
		si->audiohook.manipulate_callback = speex_callback;

		is_new = 1;
	} else {
		ast_channel_unlock(chan);
		si = datastore->data;
	}

	if (!strcasecmp(data, "rx")) {
		sdi = &si->rx;
	} else if (!strcasecmp(data, "tx")) {
		sdi = &si->tx;
	} else {
		ast_log(LOG_ERROR, "Invalid argument provided to the %s function\n", cmd);

		if (is_new) {
			ast_datastore_free(datastore);
			return -1;
		}
	}

	if (!*sdi) {
		if (!(*sdi = ast_calloc(1, sizeof(**sdi)))) {
			return 0;
		}
		/* Right now, the audiohooks API will _only_ provide us 8 kHz slinear
		 * audio.  When it supports 16 kHz (or any other sample rates, we will
		 * have to take that into account here. */
		(*sdi)->samples = -1;
	}

	if (!strcasecmp(cmd, "agc")) {
		if (!sscanf(value, "%f", &(*sdi)->agclevel))
			(*sdi)->agclevel = ast_true(value) ? DEFAULT_AGC_LEVEL : 0.0;
	
		if ((*sdi)->agclevel > 32768.0) {
			ast_log(LOG_WARNING, "AGC(%s)=%.01f is greater than 32768... setting to 32768 instead\n", 
					((*sdi == si->rx) ? "rx" : "tx"), (*sdi)->agclevel);
			(*sdi)->agclevel = 32768.0;
		}
	
		(*sdi)->agc = !!((*sdi)->agclevel);

		if ((*sdi)->state) {
			speex_preprocess_ctl((*sdi)->state, SPEEX_PREPROCESS_SET_AGC, &(*sdi)->agc);
			if ((*sdi)->agc) {
				speex_preprocess_ctl((*sdi)->state, SPEEX_PREPROCESS_SET_AGC_LEVEL, &(*sdi)->agclevel);
			}
		}
	} else if (!strcasecmp(cmd, "denoise")) {
		(*sdi)->denoise = (ast_true(value) != 0);

		if ((*sdi)->state) {
			speex_preprocess_ctl((*sdi)->state, SPEEX_PREPROCESS_SET_DENOISE, &(*sdi)->denoise);
		}
	}

	if (!(*sdi)->agc && !(*sdi)->denoise) {
		if ((*sdi)->state)
			speex_preprocess_state_destroy((*sdi)->state);

		ast_free(*sdi);
		*sdi = NULL;
	}

	if (!si->rx && !si->tx) {
		if (is_new) {
			is_new = 0;
		} else {
			ast_channel_lock(chan);
			ast_channel_datastore_remove(chan, datastore);
			ast_channel_unlock(chan);
			ast_audiohook_remove(chan, &si->audiohook);
			ast_audiohook_detach(&si->audiohook);
		}
		
		ast_datastore_free(datastore);
	}

	if (is_new) { 
		datastore->data = si;
		ast_channel_lock(chan);
		ast_channel_datastore_add(chan, datastore);
		ast_channel_unlock(chan);
		ast_audiohook_attach(chan, &si->audiohook);
	}

	return 0;
}

static int speex_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
{
	struct ast_datastore *datastore = NULL;
	struct speex_info *si = NULL;
	struct speex_direction_info *sdi = NULL;

	if (!chan) {
		ast_log(LOG_ERROR, "%s cannot be used without a channel!\n", cmd);
		return -1;
	}

	ast_channel_lock(chan);
	if (!(datastore = ast_channel_datastore_find(chan, &speex_datastore, NULL))) {
		ast_channel_unlock(chan);
		return -1;
	}
	ast_channel_unlock(chan);

	si = datastore->data;

	if (!strcasecmp(data, "tx"))
		sdi = si->tx;
	else if (!strcasecmp(data, "rx"))
		sdi = si->rx;
	else {
		ast_log(LOG_ERROR, "%s(%s) must either \"tx\" or \"rx\"\n", cmd, data);
		return -1;
	}

	if (!strcasecmp(cmd, "agc"))
		snprintf(buf, len, "%.01f", sdi ? sdi->agclevel : 0.0);
	else
		snprintf(buf, len, "%d", sdi ? sdi->denoise : 0);

	return 0;
}

static struct ast_custom_function agc_function = {
	.name = "AGC",
	.synopsis = "Apply automatic gain control to audio on a channel",
	.desc =
	"  The AGC function will apply automatic gain control to audio on the channel\n"
	"that this function is executed on.  Use rx for audio received from the channel\n"
	"and tx to apply AGC to the audio being sent to the channel.  When using this\n"
	"function, you set a target audio level.  It is primarily intended for use with\n"
	"analog lines, but could be useful for other channels, as well.  The target volume\n"
	"is set with a number between 1 and 32768.  Larger numbers are louder.\n"
	"  Example Usage:\n"
	"    Set(AGC(rx)=8000)\n"
	"    Set(AGC(tx)=8000)\n"
	"    Set(AGC(rx)=off)\n"
	"    Set(AGC(tx)=off)\n"
	"",
	.write = speex_write,
	.read = speex_read
};

static struct ast_custom_function denoise_function = {
	.name = "DENOISE",
	.synopsis = "Apply noise reduction to audio on a channel",
	.desc =
	"  The DENOISE function will apply noise reduction to audio on the channel\n"
	"that this function is executed on.  It is especially useful for noisy analog\n"
	"lines, especially when adjusting gains or using AGC.  Use rx for audio\n"
	"received from the channel and tx to apply the filter to the audio being sent\n"
	"to the channel.\n"
	"  Example Usage:\n"
	"    Set(DENOISE(rx)=on)\n"
	"    Set(DENOISE(tx)=on)\n"
	"    Set(DENOISE(rx)=off)\n"
	"    Set(DENOISE(tx)=off)\n"
	"",
	.write = speex_write,
	.read = speex_read
};

static int unload_module(void)
{
	ast_custom_function_unregister(&agc_function);
	ast_custom_function_unregister(&denoise_function);
	return 0;
}

static int load_module(void)
{
	if (ast_custom_function_register(&agc_function)) {
		return AST_MODULE_LOAD_DECLINE;
	}

	if (ast_custom_function_register(&denoise_function)) {
		ast_custom_function_unregister(&agc_function);
		return AST_MODULE_LOAD_DECLINE;
	}

	return AST_MODULE_LOAD_SUCCESS;
}

AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Noise reduction and Automatic Gain Control (AGC)");