config.c

AAC音频解码算法程序

/************************* MPEG-2 NBC Audio Decoder **************************
 *                                                                           *
"This software module was originally developed by 
AT&T, Dolby Laboratories, Fraunhofer Gesellschaft IIS in the course of 
development of the MPEG-2 NBC/MPEG-4 Audio standard ISO/IEC 13818-7, 
14496-1,2 and 3. This software module is an implementation of a part of one or more 
MPEG-2 NBC/MPEG-4 Audio tools as specified by the MPEG-2 NBC/MPEG-4 
Audio standard. ISO/IEC  gives users of the MPEG-2 NBC/MPEG-4 Audio 
standards free license to this software module or modifications thereof for use in 
hardware or software products claiming conformance to the MPEG-2 NBC/MPEG-4
Audio  standards. Those intending to use this software module in hardware or 
software products are advised that this use may infringe existing patents. 
The original developer of this software module and his/her company, the subsequent 
editors and their companies, and ISO/IEC have no liability for use of this software 
module or modifications thereof in an implementation. Copyright is not released for 
non MPEG-2 NBC/MPEG-4 Audio conforming products.The original developer
retains full right to use the code for his/her  own purpose, assign or donate the 
code to a third party and to inhibit third party from using the code for non 
MPEG-2 NBC/MPEG-4 Audio conforming products. This copyright notice must
be included in all copies or derivative works." 
Copyright(c)1996.
 *                                                                           *
 ****************************************************************************/

#include "all.h"

/*
 * profile dependent parameters
 */
int
tns_max_bands(int islong)
{
    int i;

    /* construct second index */
    i = islong ? 0 : 1;
    
    return tns_max_bands_tbl[mc_info.sampling_rate_idx][i];
}

int
tns_max_order(int islong)
{
    if (islong) {
	switch (mc_info.profile) {
	case Main_Profile:
	    return 20;
	case LC_Profile:
	    return 12;
	}
    }
    else {
	/* short window */
	return 7;
    }
    return 0;
}

int
max_indep_cc(int nch)
{
    switch (mc_info.profile) {
    case Main_Profile:
	return ICChans;
    case LC_Profile:
	return 0;
    }
    return 0;
}

int
max_dep_cc(int nch)
{
    switch (mc_info.profile) {
    case Main_Profile:
    case LC_Profile:
	return DCChans;
    }
    return 0;
}

/*
 * adif_header
 */
int get_adif_header()
{
    int i, n, tag, select_status;
    ProgConfig tmp_config;
    ADIF_Header *p = &adif_header;

    /* adif header */
	for (i=0; i<LEN_ADIF_ID; i++)
		p->adif_id[i] = (char)getbits(LEN_BYTE); 
	p->adif_id[i] = 0;	    /* null terminated string */
	/* copyright string */	
    if ((p->copy_id_present = getbits(LEN_COPYRT_PRES)) == 1) {
		for (i=0; i<LEN_COPYRT_ID; i++)
			p->copy_id[i] = (char)getbits(LEN_BYTE); 
		p->copy_id[i] = 0;  /* null terminated string */
    }
    p->original_copy = getbits(LEN_ORIG);
    p->home = getbits(LEN_HOME);
    p->bitstream_type = getbits(LEN_BS_TYPE);
    p->bitrate = getbits(LEN_BIT_RATE);

    /* program config elements */ 
    select_status = -1;   
    n = getbits(LEN_NUM_PCE) + 1;
    for (i=0; i<n; i++) {
		tmp_config.buffer_fullness =
			(p->bitstream_type == 0) ? getbits(LEN_ADIF_BF) : 0;
		tag = get_prog_config(&tmp_config);
		if (current_program < 0)
			current_program = tag;	    /* default is first prog */
		if (current_program == tag) {
			memcpy(&prog_config, &tmp_config, sizeof(prog_config));
			select_status = 1;
		}
    }

    return select_status;
}


/*
 * program configuration element
 */
void
get_ele_list(EleList *p, int enable_cpe)
{  
    int i, j;
    for (i=0, j=p->num_ele; i<j; i++) {
		if (enable_cpe)
			p->ele_is_cpe[i] = getbits(LEN_ELE_IS_CPE);
        else
            p->ele_is_cpe[i] = 0; /* sdb */
		p->ele_tag[i] = getbits(LEN_TAG);
    }
}

int
get_prog_config(ProgConfig *p)
{
    int i, j, tag;

    tag = getbits(LEN_TAG);

    p->profile = getbits(LEN_PROFILE);
    p->sampling_rate_idx = getbits(LEN_SAMP_IDX);
    p->front.num_ele = getbits(LEN_NUM_ELE);
    p->side.num_ele = getbits(LEN_NUM_ELE);
    p->back.num_ele = getbits(LEN_NUM_ELE);
    p->lfe.num_ele = getbits(LEN_NUM_LFE);
    p->data.num_ele = getbits(LEN_NUM_DAT);
    p->coupling.num_ele = getbits(LEN_NUM_CCE);
    if ((p->mono_mix.present = getbits(LEN_MIX_PRES)) == 1)
		p->mono_mix.ele_tag = getbits(LEN_TAG);
    if ((p->stereo_mix.present = getbits(LEN_MIX_PRES)) == 1)
		p->stereo_mix.ele_tag = getbits(LEN_TAG);
    if ((p->matrix_mix.present = getbits(LEN_MIX_PRES)) == 1) {
		p->matrix_mix.ele_tag = getbits(LEN_MMIX_IDX);
		p->matrix_mix.pseudo_enab = getbits(LEN_PSUR_ENAB);
    }
    get_ele_list(&p->front, 1);
    get_ele_list(&p->side, 1);
    get_ele_list(&p->back, 1);
    get_ele_list(&p->lfe, 0);
    get_ele_list(&p->data, 0);
    get_ele_list(&p->coupling, 1);
    
    byte_align();
    j = getbits(LEN_COMMENT_BYTES);
    for (i=0; i<j; i++)
		p->comments[i] = (char)getbits(LEN_BYTE);
    p->comments[i] = 0;	/* null terminator for string */

    /* activate new program configuration if appropriate */
    if (current_program < 0)
		current_program = tag;	    /* always select new program */
    if (tag == current_program) {
		/* enter configuration into MC_Info structure */
		if (enter_mc_info(&mc_info, p) < 0)
			return -1;
		/* inhibit default configuration */
		default_config = 0;
    }
	
    return tag;
}

/* enter program configuration into MC_Info structure
 *  only configures for channels specified in all.h
 */
int
enter_mc_info(MC_Info *mip, ProgConfig *pcp)
{  
    int i, j, cpe, tag, cw;
    EleList *elp;
    MIXdown *mxp;

    /* reset channel counts */
    mip->nch = 0;
    mip->nfch = 0;
    mip->nfsce = 0;
    mip->nsch = 0;
    mip->nbch = 0;
    mip->nlch = 0;
    mip->ncch = 0;

    /* profile and sampling rate
     *	re-configure if new sampling rate
     */    
    mip->profile = pcp->profile;
    if (mip->sampling_rate_idx != pcp->sampling_rate_idx) {
	mip->sampling_rate_idx = pcp->sampling_rate_idx;
	infoinit(&samp_rate_info[mip->sampling_rate_idx]);
    }
    
    cw = 0;			    /* changed later */
    
    /* front elements, center out */
    elp = &pcp->front;
    /* count number of leading SCE's */
    for (i=0, j=elp->num_ele; i<j; i++) {
	if (elp->ele_is_cpe[i])
	    break;
	mip->nfsce++;
    }
    for (i=0, j=elp->num_ele; i<j; i++) {
	cpe = elp->ele_is_cpe[i];
	tag = elp->ele_tag[i];
	if (enter_chn(cpe, tag, 'f', cw, mip) < 0)
	    return(-1);
    }
    
    /* side elements, left to right then front to back */
    elp = &pcp->side;
    for (i=0, j=elp->num_ele; i<j; i++) {
	cpe = elp->ele_is_cpe[i];
	tag = elp->ele_tag[i];
	if (enter_chn(cpe, tag, 's', cw, mip) < 0)
	    return(-1);
    }
	  
    /* back elements, outside to center */
    elp = &pcp->back;
    for (i=0, j=elp->num_ele; i<j; i++) {
	cpe = elp->ele_is_cpe[i];
	tag = elp->ele_tag[i];
	if (enter_chn(cpe, tag, 'b', cw, mip) < 0)
	     return(-1);
    }
    
    /* lfe elements */
	elp = &pcp->lfe;
    for (i=0, j=elp->num_ele; i<j; i++) {
		cpe = elp->ele_is_cpe[i];
		tag = elp->ele_tag[i];
		if (enter_chn(cpe, tag, 'l', cw, mip) < 0)
			return(-1);
    }
        
    /* coupling channel elements */
    elp = &pcp->coupling;
    for (i=0, j=elp->num_ele; i<j; i++)
	mip->cch_tag[i] = elp->ele_tag[i];
    mip->ncch = j;
    
    /* mono mixdown elements */
    mxp = &pcp->mono_mix;
    if (mxp->present) {
//		CommonWarning("Unanticipated mono mixdown channel");
		return(-1);
    }
    
    /* stereo mixdown elements */
    mxp = &pcp->stereo_mix;
    if (mxp->present) {
//	CommonWarning("Unanticipated stereo mixdown channel");
	return(-1);
    }
    
    /* matrix mixdown elements */
    mxp = &pcp->matrix_mix;
    if (mxp->present) {
//	CommonWarning("Unanticipated matrix mixdown channel");
	return(-1);
    }
    
    /* save to check future consistency */
    check_mc_info(&mc_info, 1);

    return 1;
}

/* translate prog config or default config 
 * into to multi-channel info structure
 *  returns index of channel in MC_Info
 */
int
enter_chn(int cpe, int tag, char position, int common_window, MC_Info *mip)
{
    int nch, cidx=0;
    Ch_Info *cip;

    nch = (cpe == 1) ? 2 : 1;
    
    switch (position) {
    /* use configuration already in MC_Info, but now common_window is valid */
    case 0:
	cidx = ch_index(mip, cpe, tag);