codec.c

来自「基于sip协议的网络电话源码」· C语言 代码 · 共 416 行

/* $Id: codec.c 974 2007-02-19 01:13:53Z bennylp $ */
/* 
 * Copyright (C) 2003-2007 Benny Prijono <[e-mail]>
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
#include <pjmedia/codec.h>
#include <pjmedia/errno.h>
#include <pj/array.h>
#include <pj/assert.h>
#include <pj/log.h>
#include <pj/pool.h>
#include <pj/string.h>

#define THIS_FILE   "codec.c"




/* Sort codecs in codec manager based on priorities */
static void sort_codecs(pjmedia_codec_mgr *mgr);


/*
 * Initialize codec manager.
 */
PJ_DEF(pj_status_t) pjmedia_codec_mgr_init (pjmedia_codec_mgr *mgr)
{
    PJ_ASSERT_RETURN(mgr, PJ_EINVAL);

    pj_list_init (&mgr->factory_list);
    mgr->codec_cnt = 0;

    return PJ_SUCCESS;
}


/*
 * Register a codec factory.
 */
PJ_DEF(pj_status_t) 
pjmedia_codec_mgr_register_factory( pjmedia_codec_mgr *mgr,
				    pjmedia_codec_factory *factory)
{
    pjmedia_codec_info info[PJMEDIA_CODEC_MGR_MAX_CODECS];
    unsigned i, count;
    pj_status_t status;

    PJ_ASSERT_RETURN(mgr && factory, PJ_EINVAL);

    /* Enum codecs */
    count = PJ_ARRAY_SIZE(info);
    status = factory->op->enum_info(factory, &count, info);
    if (status != PJ_SUCCESS)
	return status;
    

    /* Check codec count */
    if (count + mgr->codec_cnt > PJ_ARRAY_SIZE(mgr->codec_desc))
	return PJ_ETOOMANY;


    /* Save the codecs */
    for (i=0; i<count; ++i) {
	pj_memcpy( &mgr->codec_desc[mgr->codec_cnt+i],
		   &info[i], sizeof(pjmedia_codec_info));
	mgr->codec_desc[mgr->codec_cnt+i].prio = PJMEDIA_CODEC_PRIO_NORMAL;
	mgr->codec_desc[mgr->codec_cnt+i].factory = factory;
	pjmedia_codec_info_to_id( &info[i],
				  mgr->codec_desc[mgr->codec_cnt+i].id,
				  sizeof(pjmedia_codec_id));
    }

    /* Update count */
    mgr->codec_cnt += count;

    /* Re-sort codec based on priorities */
    sort_codecs(mgr);

    /* Add factory to the list */
    pj_list_push_back(&mgr->factory_list, factory);


    return PJ_SUCCESS;
}


/*
 * Unregister a codec factory.
 */
PJ_DEF(pj_status_t) 
pjmedia_codec_mgr_unregister_factory(pjmedia_codec_mgr *mgr, 
				     pjmedia_codec_factory *factory)
{
    unsigned i;
    PJ_ASSERT_RETURN(mgr && factory, PJ_EINVAL);

    /* Factory must be registered. */
    PJ_ASSERT_RETURN(pj_list_find_node(&mgr->factory_list, factory)==factory,
		     PJ_ENOTFOUND);

    /* Erase factory from the factory list */
    pj_list_erase(factory);


    /* Remove all supported codecs from the codec manager that were created 
     * by the specified factory.
     */
    for (i=0; i<mgr->codec_cnt; ) {

	if (mgr->codec_desc[i].factory == factory) {

	    pj_array_erase(mgr->codec_desc, sizeof(mgr->codec_desc[0]), 
			   mgr->codec_cnt, i);
	    --mgr->codec_cnt;

	} else {
	    ++i;
	}
    }


    return PJ_SUCCESS;
}


/*
 * Enum all codecs.
 */
PJ_DEF(pj_status_t)
pjmedia_codec_mgr_enum_codecs(pjmedia_codec_mgr *mgr, 
			      unsigned *count, 
			      pjmedia_codec_info codecs[],
			      unsigned *prio)
{
    unsigned i;

    PJ_ASSERT_RETURN(mgr && count && codecs, PJ_EINVAL);

    if (*count > mgr->codec_cnt)
	*count = mgr->codec_cnt;
    
    for (i=0; i<*count; ++i) {
	pj_memcpy(&codecs[i], 
		  &mgr->codec_desc[i].info, 
		  sizeof(pjmedia_codec_info));
    }

    if (prio) {
	for (i=0; i < *count; ++i)
	    prio[i] = mgr->codec_desc[i].prio;
    }

    return PJ_SUCCESS;
}


/*
 * Get codec info for static payload type.
 */
PJ_DEF(pj_status_t) 
pjmedia_codec_mgr_get_codec_info( pjmedia_codec_mgr *mgr,
				  unsigned pt,
				  const pjmedia_codec_info **p_info)
{
    unsigned i;

    PJ_ASSERT_RETURN(mgr && p_info && pt>=0 && pt < 96, PJ_EINVAL);

    for (i=0; i<mgr->codec_cnt; ++i) {
	if (mgr->codec_desc[i].info.pt == pt) {
	    *p_info = &mgr->codec_desc[i].info;
	    return PJ_SUCCESS;
	}
    }

    return PJMEDIA_CODEC_EUNSUP;
}


/*
 * Convert codec info struct into a unique codec identifier.
 * A codec identifier looks something like "L16/44100/2".
 */
PJ_DEF(char*) pjmedia_codec_info_to_id( const pjmedia_codec_info *info,
				        char *id, unsigned max_len )
{
    int len;

    PJ_ASSERT_RETURN(info && id && max_len, NULL);

    len = pj_ansi_snprintf(id, max_len, "%.*s/%u/%u", 
			   (int)info->encoding_name.slen,
			   info->encoding_name.ptr,
			   info->clock_rate,
			   info->channel_cnt);

    if (len < 1 || len >= (int)max_len) {
	id[0] = '\0';
	return NULL;
    }

    return id;
}


/*
 * Find codecs by the unique codec identifier. This function will find
 * all codecs that match the codec identifier prefix. For example, if
 * "L16" is specified, then it will find "L16/8000/1", "L16/16000/1",
 * and so on, up to the maximum count specified in the argument.
 */
PJ_DEF(pj_status_t) 
pjmedia_codec_mgr_find_codecs_by_id( pjmedia_codec_mgr *mgr,
				     const pj_str_t *codec_id,
				     unsigned *count,
				     const pjmedia_codec_info *p_info[],
				     unsigned prio[])
{
    unsigned i, found = 0;

    PJ_ASSERT_RETURN(mgr && codec_id && count && *count, PJ_EINVAL);

    for (i=0; i<mgr->codec_cnt; ++i) {

	if (pj_strnicmp2(codec_id, mgr->codec_desc[i].id, 
			 codec_id->slen) == 0) 
	{

	    if (p_info)
		p_info[found] = &mgr->codec_desc[i].info;
	    if (prio)
		prio[found] = mgr->codec_desc[i].prio;

	    ++found;

	    if (found >= *count)
		break;
	}

    }

    *count = found;

    return found ? PJ_SUCCESS : PJ_ENOTFOUND;
}


/* Swap two codecs positions in codec manager */
static void swap_codec(pjmedia_codec_mgr *mgr, unsigned i, unsigned j)
{
    struct pjmedia_codec_desc tmp;

    pj_memcpy(&tmp, &mgr->codec_desc[i], sizeof(struct pjmedia_codec_desc));

    pj_memcpy(&mgr->codec_desc[i], &mgr->codec_desc[j], 
	       sizeof(struct pjmedia_codec_desc));

    pj_memcpy(&mgr->codec_desc[j], &tmp, sizeof(struct pjmedia_codec_desc));
}


/* Sort codecs in codec manager based on priorities */
static void sort_codecs(pjmedia_codec_mgr *mgr)
{
    unsigned i;

   /* Re-sort */
    for (i=0; i<mgr->codec_cnt; ++i) {
	unsigned j, max;

	for (max=i, j=i+1; j<mgr->codec_cnt; ++j) {
	    if (mgr->codec_desc[j].prio > mgr->codec_desc[max].prio)
		max = j;
	}

	if (max != i)
	    swap_codec(mgr, i, max);
    }

    /* Change PJMEDIA_CODEC_PRIO_HIGHEST codecs to NEXT_HIGHER */
    for (i=0; i<mgr->codec_cnt; ++i) {
	if (mgr->codec_desc[i].prio == PJMEDIA_CODEC_PRIO_HIGHEST)
	    mgr->codec_desc[i].prio = PJMEDIA_CODEC_PRIO_NEXT_HIGHER;
	else
	    break;
    }
}


/**
 * Set codec priority. The codec priority determines the order of
 * the codec in the SDP created by the endpoint. If more than one codecs
 * are found with the same codec_id prefix, then the function sets the
 * priorities of all those codecs.
 */
PJ_DEF(pj_status_t)
pjmedia_codec_mgr_set_codec_priority(pjmedia_codec_mgr *mgr, 
				     const pj_str_t *codec_id,
				     pj_uint8_t prio)
{
    unsigned i, found = 0;

    PJ_ASSERT_RETURN(mgr && codec_id, PJ_EINVAL);

    /* Update the priorities of affected codecs */
    for (i=0; i<mgr->codec_cnt; ++i) 
    {
	if (codec_id->slen == 0 ||
	    pj_strnicmp2(codec_id, mgr->codec_desc[i].id, 
			 codec_id->slen) == 0) 
	{
	    mgr->codec_desc[i].prio = prio;
	    ++found;
	}
    }

    if (!found)
	return PJ_ENOTFOUND;

    /* Re-sort codecs */
    sort_codecs(mgr);
 

    return PJ_SUCCESS;
}


/*
 * Allocate one codec.
 */
PJ_DEF(pj_status_t) pjmedia_codec_mgr_alloc_codec(pjmedia_codec_mgr *mgr, 
						  const pjmedia_codec_info *info,
						  pjmedia_codec **p_codec)
{
    pjmedia_codec_factory *factory;
    pj_status_t status;

    PJ_ASSERT_RETURN(mgr && info && p_codec, PJ_EINVAL);

    *p_codec = NULL;

    factory = mgr->factory_list.next;
    while (factory != &mgr->factory_list) {

	if ( (*factory->op->test_alloc)(factory, info) == PJ_SUCCESS ) {

	    status = (*factory->op->alloc_codec)(factory, info, p_codec);
	    if (status == PJ_SUCCESS)
		return PJ_SUCCESS;

	}

	factory = factory->next;
    }


    return PJMEDIA_CODEC_EUNSUP;
}


/*
 * Get default codec parameter.
 */
PJ_DEF(pj_status_t) pjmedia_codec_mgr_get_default_param( pjmedia_codec_mgr *mgr,
							const pjmedia_codec_info *info,
							pjmedia_codec_param *param )
{
    pjmedia_codec_factory *factory;
    pj_status_t status;

    PJ_ASSERT_RETURN(mgr && info && param, PJ_EINVAL);

    factory = mgr->factory_list.next;
    while (factory != &mgr->factory_list) {

	if ( (*factory->op->test_alloc)(factory, info) == PJ_SUCCESS ) {

	    status = (*factory->op->default_attr)(factory, info, param);
	    if (status == PJ_SUCCESS)
		return PJ_SUCCESS;

	}

	factory = factory->next;
    }


    return PJMEDIA_CODEC_EUNSUP;
}


/*
 * Dealloc codec.
 */
PJ_DEF(pj_status_t) pjmedia_codec_mgr_dealloc_codec(pjmedia_codec_mgr *mgr, 
						    pjmedia_codec *codec)
{
    PJ_ASSERT_RETURN(mgr && codec, PJ_EINVAL);

    return (*codec->factory->op->dealloc_codec)(codec->factory, codec);
}