freeswitch/src/mod/codecs/mod_amr/mod_amr.c

/* 
 * FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 * Copyright (C) 2005/2006, Anthony Minessale II <anthmct@yahoo.com>
 *
 * Version: MPL 1.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 *
 * The Initial Developer of the Original Code is
 * Anthony Minessale II <anthmct@yahoo.com>
 * Portions created by the Initial Developer are Copyright (C)
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 * 
 * Anthony Minessale II <anthmct@yahoo.com>
 * Brian K. West <brian.west@mac.com>
 *
 * The amr codec itself is not distributed with this module.
 *
 * mod_amr.c -- GSM-AMR Codec Module
 *
 */  
#include "switch.h"
static const char modname[] = "mod_amr";

#ifndef AMR_PASSTHROUGH
#include "amr/interf_enc.h"
#include "amr/interf_dec.h"

/*
 * Check section 8.1 of rfc3267 for possible sdp options.
 *  
 * SDP Example 
 * 
 * a=fmtp:97 mode-set=0,2,5,7; mode-change-period=2; mode-change-neighbor=1
 *
 *                                 Class A   total speech
 *                Index   Mode       bits       bits
 *                ----------------------------------------
 *                  0     AMR 4.75   42         95
 *                  1     AMR 5.15   49        103
 *                  2     AMR 5.9    55        118
 *                  3     AMR 6.7    58        134
 *                  4     AMR 7.4    61        148
 *                  5     AMR 7.95   75        159
 *                  6     AMR 10.2   65        204
 *                  7     AMR 12.2   81        244
 *                  8     AMR SID    39         39
 *
 *        Table 1.  The number of class A bits for the AMR codec.
 *
 */

typedef enum {
	AMR_OPT_OCTET_ALIGN = (1 << 0),
	AMR_OPT_CRC = (1 << 1),
	AMR_OPT_MODE_CHANGE_NEIGHBOR = (1 << 2),
	AMR_OPT_ROBUST_SORTING = (1 << 3),
	AMR_OPT_INTERLEAVING = (1 << 4)
} amr_flag_t;


typedef enum {
	GENERIC_PARAMETER_AMR_MAXAL_SDUFRAMES = 0,
	GENERIC_PARAMETER_AMR_BITRATE,
	GENERIC_PARAMETER_AMR_GSMAMRCOMFORTNOISE,
	GENERIC_PARAMETER_AMR_GSMEFRCOMFORTNOISE,
	GENERIC_PARAMETER_AMR_IS_641COMFORTNOISE,
	GENERIC_PARAMETER_AMR_PDCEFRCOMFORTNOISE
} amr_param_t;

typedef enum {
	AMR_BITRATE_475 = 0,
	AMR_BITRATE_515,
	AMR_BITRATE_590,
	AMR_BITRATE_670,
	AMR_BITRATE_740,
	AMR_BITRATE_795,
	AMR_BITRATE_1020,
	AMR_BITRATE_1220
} amr_bitrate_t;


struct amr_context {
	void *encoder_state;
	void *decoder_state;
	switch_byte_t enc_modes;
	switch_byte_t enc_mode;
	uint32_t change_period;
	switch_byte_t max_ptime;
	switch_byte_t ptime;
	switch_byte_t channels;
	switch_byte_t flags;
};


#define AMR_DEFAULT_BITRATE AMR_BITRATE_1220

static struct {
	switch_byte_t default_bitrate;
} globals;

#endif

static switch_status_t switch_amr_init(switch_codec_t *codec, switch_codec_flag_t flags,
									  const switch_codec_settings_t *codec_settings) 
{

#ifdef AMR_PASSTHROUGH
	codec->flags |= SWITCH_CODEC_FLAG_PASSTHROUGH;
    if (codec->fmtp_in) {
        codec->fmtp_out = switch_core_strdup(codec->memory_pool, codec->fmtp_in);
    }
	return SWITCH_STATUS_SUCCESS;
#else
	struct amr_context *context = NULL;
	int encoding, decoding;
	int x, i, argc;
	char *argv[10];
	char fmtptmp[128];

	encoding = (flags & SWITCH_CODEC_FLAG_ENCODE);
	decoding = (flags & SWITCH_CODEC_FLAG_DECODE);

	if (!(encoding || decoding) || (!(context = switch_core_alloc(codec->memory_pool, sizeof(struct amr_context))))) {
		return SWITCH_STATUS_FALSE;
	} else {

		if (codec->fmtp_in) {
			argc = switch_separate_string(codec->fmtp_in, ';', argv, (sizeof(argv) / sizeof(argv[0])));
			for(x = 0; x < argc; x++) {
				char *data = argv[x];
				char *arg;
				while(*data && *data == ' ') {
					data++;
				}
				if ((arg = strchr(data, '='))) {
					*arg++ = '\0';
					//printf("Codec arg %d [%s]=[%s]\n", x, data, arg);
					if (!strcasecmp(data, "octet-align")) {
						if (atoi(arg)) {
							switch_set_flag(context, AMR_OPT_OCTET_ALIGN);
						}
					} else if (!strcasecmp(data, "mode-change-neighbor")) {
						if (atoi(arg)) {
							switch_set_flag(context, AMR_OPT_MODE_CHANGE_NEIGHBOR);
						}
					} else if (!strcasecmp(data, "crc")) {
						if (atoi(arg)) {
							switch_set_flag(context, AMR_OPT_CRC);
						}
					} else if (!strcasecmp(data, "robust-sorting")) {
						if (atoi(arg)) {
							switch_set_flag(context, AMR_OPT_ROBUST_SORTING);
						}
					} else if (!strcasecmp(data, "interveaving")) {
						if (atoi(arg)) {
							switch_set_flag(context, AMR_OPT_INTERLEAVING);
						}
					} else if (!strcasecmp(data, "mode-change-period")) {
						context->change_period = atoi(arg);
					} else if (!strcasecmp(data, "ptime")) {
						context->ptime = (switch_byte_t)atoi(arg);
					} else if (!strcasecmp(data, "channels")) {
						context->channels = (switch_byte_t)atoi(arg);
					} else if (!strcasecmp(data, "maxptime")) {
						context->max_ptime = (switch_byte_t)atoi(arg);
					} else if (!strcasecmp(data, "mode-set")) {
						int y, m_argc;
						char *m_argv[7];
						m_argc = switch_separate_string(arg, ',', m_argv, (sizeof(m_argv) / sizeof(m_argv[0])));
						for(y = 0; y < m_argc; y++) {
							context->enc_modes |= (1 << atoi(m_argv[y]));
						}
					}
				}

			}
		}

		if (context->enc_modes) {
			for (i = 7; i > -1; i++) {
				if (context->enc_modes & (1 << i)) {
					context->enc_mode = (switch_byte_t)i;
					break;
				}
			}
		}

		if (!context->enc_mode) {
			context->enc_mode = globals.default_bitrate;
		}
		
		snprintf(fmtptmp, sizeof(fmtptmp), "octet-align=%d; mode-set=%d", switch_test_flag(context, AMR_OPT_OCTET_ALIGN) ? 1 : 0, context->enc_mode);
		codec->fmtp_out = switch_core_strdup(codec->memory_pool, fmtptmp);
		
		context->enc_mode = AMR_DEFAULT_BITRATE;
		context->encoder_state = NULL;
		context->decoder_state = NULL;

		if (encoding) {
			context->encoder_state = Encoder_Interface_init(1);
		}

		if (decoding) {
			context->decoder_state = Decoder_Interface_init();
		}

		codec->private_info = context;

		return SWITCH_STATUS_SUCCESS;
	}
#endif
}

static switch_status_t switch_amr_destroy(switch_codec_t *codec) 
{
#ifndef AMR_PASSTHROUGH
	struct amr_context *context = codec->private_info;

	if (context->encoder_state) {
		Encoder_Interface_exit(context->encoder_state);
	}
	if (context->decoder_state) {
		Decoder_Interface_exit(context->decoder_state);
	}
	codec->private_info = NULL;
#endif
	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t switch_amr_encode(switch_codec_t *codec, 
										switch_codec_t *other_codec, 
										void *decoded_data,

										uint32_t decoded_data_len, 
										uint32_t decoded_rate, 
										void *encoded_data,

										uint32_t *encoded_data_len, 
										uint32_t *encoded_rate, 
										unsigned int *flag) 
{
#ifdef AMR_PASSTHROUGH
	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "This codec is only usable in passthrough mode!\n");
	return SWITCH_STATUS_FALSE;
#else
	struct amr_context *context = codec->private_info;
	
	if (!context) {
		return SWITCH_STATUS_FALSE;
	}
	
	*encoded_data_len = Encoder_Interface_Encode( context->encoder_state, context->enc_mode, (int16_t *)decoded_data, (switch_byte_t *) encoded_data, 0);

	return SWITCH_STATUS_SUCCESS;
#endif
}

static switch_status_t switch_amr_decode(switch_codec_t *codec, 
										switch_codec_t *other_codec, 
										void *encoded_data,

										uint32_t encoded_data_len, 
										uint32_t encoded_rate, 
										void *decoded_data,

										uint32_t *decoded_data_len, 
										uint32_t *decoded_rate, 
										unsigned int *flag) 
{
#ifdef AMR_PASSTHROUGH
	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "This codec is only usable in passthrough mode!\n");
	return SWITCH_STATUS_FALSE;
#else
	struct amr_context *context = codec->private_info;

	if (!context) {
		return SWITCH_STATUS_FALSE;
	}

	Decoder_Interface_Decode(context->decoder_state, (unsigned char *)encoded_data, (int16_t *)decoded_data, 0);
	*decoded_data_len = codec->implementation->bytes_per_frame;

	return SWITCH_STATUS_SUCCESS;
#endif
}

/* Registration */ 

static const switch_codec_implementation_t amr_implementation = { 
	/*.codec_type */ SWITCH_CODEC_TYPE_AUDIO, 
	/*.ianacode */ 96, 
	/*.iananame */ "AMR", 
	/*.fmtp */ "octet-align=0",
	/*.samples_per_second */ 8000, 
	/*.bits_per_second */ 0, 
	/*.microseconds_per_frame */ 20000, 
	/*.samples_per_frame */ 160, 
	/*.bytes_per_frame */ 320,
	/*.encoded_bytes_per_frame */ 0, 
	/*.number_of_channels */ 1, 
	/*.pref_frames_per_packet */ 1, 
	/*.max_frames_per_packet */ 1, 
	/*.init */ switch_amr_init, 
	/*.encode */ switch_amr_encode, 
	/*.decode */ switch_amr_decode, 
	/*.destroy */ switch_amr_destroy, 
};

static const switch_codec_interface_t amr_codec_interface = { 
	/*.interface_name */ "GSM-AMR", 
	/*.implementations */ &amr_implementation, 
};

static switch_loadable_module_interface_t amr_module_interface = { 
	/*.module_name */ modname, 
	/*.endpoint_interface */ NULL, 
	/*.timer_interface */ NULL, 
	/*.dialplan_interface */ NULL, 
	/*.codec_interface */ &amr_codec_interface, 
	/*.application_interface */ NULL 
};

SWITCH_MOD_DECLARE(switch_status_t) switch_module_load(const switch_loadable_module_interface_t **module_interface,
													 char *filename)
{
#ifndef AMR_PASSTHROUGH
	char *cf = "amr.conf";
	switch_xml_t cfg, xml, settings, param;

	memset(&globals, 0, sizeof(globals));
	globals.default_bitrate = AMR_DEFAULT_BITRATE;

	if ((xml = switch_xml_open_cfg(cf, &cfg, NULL))) {
		if ((settings = switch_xml_child(cfg, "settings"))) {
			for (param = switch_xml_child(settings, "param"); param; param = param->next) {
				char *var = (char *) switch_xml_attr_soft(param, "name");
				char *val = (char *) switch_xml_attr_soft(param, "value");
				if (!strcasecmp(var, "default-bitrate")) {
					globals.default_bitrate = (switch_byte_t)atoi(val);
				}
			}
		}
	}

#endif

	/* connect my internal structure to the blank pointer passed to me */ 
	*module_interface = &amr_module_interface;

	/* indicate that the module should continue to be loaded */ 
	return SWITCH_STATUS_SUCCESS;
}