common.c

MPEG 2的音频编码软件。喜欢多媒体的开发人员可以看看。

	return (1);
}

int dyn_bbal (int config, int center, int dynx, int sbgr)
{
    /* 960627 FdB Dyn_ch table dependent on configuration */
    if (config == 320)
    {
	if (center == 3)
	    return (dyn_bbal4PhC[dynx][sbgr]);
	else
	    return (dyn_bbal4[dynx][sbgr]);
    }
    else if (config == 310 || config == 220)
    {
	if (center == 3)
	    return (dyn_bbal3PhC[dynx][sbgr]);
	else
	    return (dyn_bbal3[dynx][sbgr]);
    }
    else if (config == 300 || config == 302 || config == 210)
    {
	if (center == 3)
	    return (dyn_bbal1PhC[dynx][sbgr]);
	else
	    return (dyn_bbal1[dynx][sbgr]);
    }
    else
	return (0);
}

int dyn_bbal_2ndst (int dynx, int sbgr)
{
    return (dyn_bbal4[dynx][sbgr]);
}


#ifdef Augmentation_7ch
int dyn_bbal_aug (int aug_dynx, int sbgr)
{
    /* 960627 FdB Dyn_ch table dependent on configuration */
    return (dyn_bbal5[aug_dynx][sbgr]);
}
#endif

void init_mc_pred (frame_params *fr_ps)
{
    layer *info = fr_ps->header;
    int i, j, k;

    switch (fr_ps->config)
    {
    case 320:	for (i = 0; i < 16; i++) n_pred_coef[i] = n_pred_coef4[i]; break;
    case 310:
    case 220:	for (i = 0; i < 16; i++) n_pred_coef[i] = n_pred_coef3[i]; break;
    case 300:
    case 302:
    case 210:	for (i = 0; i < 16; i++) n_pred_coef[i] = n_pred_coef1[i]; break;
    default:	for (i = 0; i < 16; i++) n_pred_coef[i] = 0; break;
    }

    for (i = 0; i < 8; i++)
    {
	info->mc_pred[i] = 0;
	for (j = 0; j < 6; j++)
	{
	    info->delay_comp[i][j] = 0;
	    info->predsi[i][j] = 0;
	    for (k = 0; k < 3; k++)
		info->pred_coef[i][j][k] = 127;
	}  
    }
}

void set_mc_pred (frame_params *fr_ps)
{
    layer *info = fr_ps->header;
    int config = fr_ps->config;
    int dynx;
    int i, j, k, npred;

    for (i = 0; i < 8; i++)
    {
	info->mc_pred[i] = rand () % 2;
	if (info->mc_pred[i])
	{
	    dynx = fr_ps->header->dyn_cross[i];
	    npred = n_pred_coef[dynx];
	    for (j = 0; j < npred; j++)
	    {
		info->predsi[i][j] = rand () % 4;
		if (info->predsi[i][j])
		{
		    info->delay_comp[i][j] = rand () % 8;
		    for (k = 0; k < info->predsi[i][j]; k++)
			info->pred_coef[i][j][k] = rand () % 256;
		}
	    }  
	}
    }
}

/*****************************************************************************
*
*  CRC error protection package
*
*****************************************************************************/

void I_CRC_calc (frame_params *fr_ps, unsigned int (*bit_alloc)[32], unsigned int *crc)
{
    int i, k;
    layer *info = fr_ps->header;
    int stereo  = fr_ps->stereo;
    int jsbound = fr_ps->jsbound;

    *crc = 0xffff; /* changed from '0' 92-08-11 shn */
    update_CRC(info->bitrate_index, 4, crc);
    update_CRC(info->sampling_frequency, 2, crc);
    update_CRC(info->padding, 1, crc);
    update_CRC(info->extension, 1, crc);
    update_CRC(info->mode, 2, crc);
    update_CRC(info->mode_ext, 2, crc);
    update_CRC(info->copyright, 1, crc);
    update_CRC(info->original, 1, crc);
    update_CRC(info->emphasis, 2, crc);

    for (i=0;i<SBLIMIT;i++)
	    for (k=0;k<((i<jsbound)?stereo:1);k++)
		    update_CRC(bit_alloc[k][i], 4, crc);
}

void II_CRC_calc (frame_params *fr_ps, unsigned int (*bit_alloc)[32], unsigned int (*scfsi)[32], unsigned int *crc)
{
    int i, k;
    layer *info = fr_ps->header;
    int stereo  = fr_ps->stereo;
    int sblimit = fr_ps->sblimit;
    int jsbound = fr_ps->jsbound;
    al_table *alloc = fr_ps->alloc;

    *crc = 0xffff; /* changed from '0' 92-08-11 shn */
    update_CRC(info->bitrate_index, 4, crc);
    update_CRC(info->sampling_frequency, 2, crc);
    update_CRC(info->padding, 1, crc);
    update_CRC(info->extension, 1, crc);
    update_CRC(info->mode, 2, crc);
    update_CRC(info->mode_ext, 2, crc);
    update_CRC(info->copyright, 1, crc);
    update_CRC(info->original, 1, crc);
    update_CRC(info->emphasis, 2, crc);

    for (i=0;i<sblimit;i++)
	    for (k=0;k<((i<jsbound)?stereo:1);k++)
		    update_CRC(bit_alloc[k][i], (*alloc)[i][0].bits, crc);

    for (i=0;i<sblimit;i++)
	    for (k=0;k<stereo;k++)
		    if (bit_alloc[k][i])
			    update_CRC(scfsi[k][i], 2, crc);
}

void II_CRC_calc_mc (frame_params *fr_ps, unsigned int (*bit_alloc)[32], unsigned int lfe_alloc, unsigned int (*scfsi)[32], unsigned int *crc)
{
    int i, k, m, l;
    layer *info  = fr_ps->header;
    int nr_tc    = fr_ps->stereo + fr_ps->stereomc;
    int center   = info->center;
    int surround = info->surround;
    int sblimit  = fr_ps->sblimit_mc;
    al_table *alloc = fr_ps->alloc_mc;
    
    *crc = 0xffff; /* changed from '0' 92-08-11 shn */
    update_CRC(info->ext_bit_stream_present, 1, crc);
    if(info->ext_bit_stream_present == 1)
        update_CRC(info->n_ad_bytes, 8, crc);
    update_CRC(center, 2, crc);
    update_CRC(surround, 2, crc);
    update_CRC(info->lfe, 1, crc);
    update_CRC(info->audio_mix, 1, crc);
    update_CRC(info->matrix, 2, crc);
    update_CRC(info->multiling_ch, 3, crc);
    update_CRC(info->multiling_fs, 1, crc);
    update_CRC(info->multiling_lay, 1, crc);
    update_CRC(info->copy_ident_bit, 1, crc);
    update_CRC(info->copy_ident_start, 1, crc);
    
    update_CRC(info->tc_sbgr_select, 1, crc);
    update_CRC(info->dyn_cross_on, 1, crc);
    update_CRC(info->mc_prediction_on, 1, crc);
    /* 960627 FdB tca bits dependent on configuration */
    if ((center == 1 || center == 3) &&
        (surround == 1 || surround == 2))
    {
	/* 3 bits for tca's */
	if(info->tc_sbgr_select == 1)
	    update_CRC(info->tc_allocation, 3, crc);
	else
	    for(i = 0; i < 12; i++)
		update_CRC(info->tc_alloc[i], 3, crc);
    }
    else if (center == 1 || center == 3 || surround == 1 || surround == 2)
    {
	/* 2 bits for tca's */
	if(info->tc_sbgr_select == 1)
	    update_CRC(info->tc_allocation, 2, crc);
	else
	    for(i = 0; i < 12; i++)
		update_CRC(info->tc_alloc[i], 2, crc);
    }
    if(info->dyn_cross_on == 1)
    {
      update_CRC(info->dyn_cross_LR, 1, crc);
	for(i = 0; i < 12; i++)
	{
	    /* 960627 FdB DynX bits dependent on configuration */
	    if((center == 1 || center == 3) && surround == 2)
		/* 3/2 */
		update_CRC(info->dyn_cross[i], 4, crc);
	    else if(((center == 1 || center == 3) && surround == 1) ||
		    (center == 0 && surround == 2))
		/* 3/1 and 2/2 */
		update_CRC(info->dyn_cross[i], 3, crc);
	    else if(center == 1 || center == 3 || surround == 1)
		/* 3/0 (+2/0) and 2/1 */
		update_CRC(info->dyn_cross[i], 1, crc);
	    if(surround == 3)
		update_CRC(info->dyn_second_stereo[i], 1, crc);
	}	  
    }	  

    if (info->mc_prediction_on == 1)
    {
	for(i = 0; i < 8; i++)
	{
	    update_CRC (info->mc_pred[i], 1, crc);
	    if (info->mc_pred[i] == 1)
	        for (k = 0; k < n_pred_coef[info->dyn_cross[i]]; k ++)
		    update_CRC (info->predsi[i][k], 2, crc);
	}
    }
    
    if (fr_ps->header->lfe == 1)
        update_CRC (lfe_alloc, (*alloc)[0][0].bits, crc);	    
	    
    for (i = 0; i < sblimit; i++)
    {
	l = sbgrp[i];

	for (m = fr_ps->stereo; m < fr_ps->stereo + fr_ps->stereomc; m++)
	{        
	    k = transmission_channel (fr_ps, l, m);

	    if ((i < 12) || (k != 2) || (fr_ps->header->center != 3))
	    {
		/* 960627 FdB DynX dependent on configuration */
		if (dyn_ch (fr_ps, l, m) == 1)
		    update_CRC (bit_alloc[k][i], (*alloc)[i][0].bits, crc);
	    }	     
	}	
    }

    for (i = 0; i < sblimit; i++)
    {
	l = sbgrp[i];

	for (m = fr_ps->stereo; m < fr_ps->stereo + fr_ps->stereomc; m++)
        {        
	    k = transmission_channel (fr_ps, l, m);
 
	    if (bit_alloc[k][i] && (i < 12 || m != 2 || center != 3))
		update_CRC (scfsi[k][i], 2, crc);
	}
    }
}

#ifdef Augmentation_7ch
void II_CRC_calc_aug (frame_params *fr_ps, unsigned int (*bit_alloc)[32], unsigned int (*scfsi)[32], unsigned int *crc)
{
    int i, k, m, l;
    int aug_future_ext = 0;
    layer *info  = fr_ps->header;
    int sblimit  = fr_ps->sblimit_mc;
    al_table *alloc = fr_ps->alloc_mc;
    
    *crc = 0xffff; /* changed from '0' 92-08-11 shn */
    update_CRC (info->aug_mtx_proc, 2, crc);
    update_CRC (info->aug_dyn_cross_on, 1, crc);
    update_CRC (aug_future_ext, 1, crc);
    /* 960627 FdB aug tca bits dependent on configuration */
    if (info->aug_mtx_proc == 0)
	for (i = 0; i < 12; i++)
	    update_CRC (info->aug_tc_alloc[i], 3, crc);
    else if (info->aug_mtx_proc == 1)
	for (i = 0; i < 12; i++)
	    update_CRC (info->aug_tc_alloc[i], 2, crc);
    if (info->aug_dyn_cross_on == 1)
	for (i = 0; i < 12; i++)
	    update_CRC (info->aug_dyn_cross[i], 5, crc);

    for (i = 0; i < sblimit; i++)
    {
	l = sbgrp[i];

	for (m = 5; m < 7; ++m)
	{        
	    k = transmission_channel (fr_ps, l, m);

	    if (dyn_ch (fr_ps, l, m) == 1)
		update_CRC (bit_alloc[k][i], (*alloc)[i][0].bits, crc);
	}	
    }

    for (i = 0; i < sblimit; i++)
    {
	l = sbgrp[i];

	for (m = 5; m < 7; ++m)
        {        
	    k = transmission_channel (fr_ps, l, m);
 
	    if (bit_alloc[k][i])
		update_CRC (scfsi[k][i], 2, crc);
	}
    }
}
#endif


void II_CRC_calc_ext (frame_params *fr_ps, unsigned int *z, unsigned int *crc)
{
    int i;

    layer *info = fr_ps->header;
    *crc = 0xffff; 
    update_CRC (info->ext_length, 11, crc);
    update_CRC (info->ext_bit, 1, crc);
    for (i = 0; i < 14; i++)
    {
	update_CRC (z[i], 8, crc);
    }
    update_CRC (z[14], 4, crc);
}


void update_CRC (unsigned int data, unsigned int length, unsigned int *crc)
{
    unsigned int  masking, carry;

    masking = 1 << length;

    while (masking >>= 1)
    {
	carry = *crc & 0x8000;
	*crc <<= 1;
	if (!carry ^ !(data & masking))
	    *crc ^= CRC16_POLYNOMIAL;
    }
    *crc &= 0xffff;

#ifdef	PrintCRCDebug
	printf ("crc_len: %2d code: %4x crc: %4x\n", length, data, *crc);
	fflush (stdout);
#endif
}

/*****************************************************************************
*
*  End of CRC error protection package
*
*****************************************************************************/

#ifdef  MACINTOSH
/*****************************************************************************
*
*  Set Macintosh file attributes.
*
*****************************************************************************/

void    set_mac_file_attr(fileName, vRefNum, creator, fileType)
char    fileName[MAX_NAME_SIZE];
short   vRefNum;
OsType  creator;
OsType  fileType;
{

short   theFile;
char    pascal_fileName[MAX_NAME_SIZE];
FInfo   fndrInfo;

        CtoPstr(strcpy(pascal_fileName, fileName));

        FSOpen(pascal_fileName, vRefNum, &theFile);
        GetFInfo(pascal_fileName, vRefNum, &fndrInfo);
        fndrInfo.fdCreator = creator;
        fndrInfo.fdType = fileType;
        SetFInfo(pascal_fileName, vRefNum, &fndrInfo);
        FSClose(theFile);

}
#endif