void pvmp3_mpeg2_get_scale_factors(mp3ScaleFactors *scalefac,
mp3SideInfo *si,
int32 gr,
int32 ch,
mp3Header *info,
uint32 *scalefac_IIP_buffer,
tmp3Bits *pMainData)
{
int32 sfb;
int32 k = 0;
int32 window;
uint32 *scalefac_buffer = &scalefac_IIP_buffer[56];
granuleInfo *gr_info = &(si->ch[ch].gran[gr]);
pvmp3_mpeg2_get_scale_data(si,
gr,
ch,
info,
(uint32 *)scalefac_buffer,
(uint32 *)scalefac_IIP_buffer,
pMainData);
if (gr_info->window_switching_flag && (gr_info->block_type == 2))
{
if (gr_info->mixed_block_flag)
{
for (sfb = 0; sfb < 6; sfb++)
{
scalefac->l[sfb] = scalefac_buffer[sfb];
}
k = 6;
for (sfb = 3; sfb < 12; sfb++)
{
for (window = 0; window < 3; window++)
{
scalefac->s[window][sfb] = scalefac_buffer[k];
k++;
}
}
/* adjust position of "illegal position" information in scalefac_IIP_buffer[] */
/* in mixed blocks mode for short sfb, move them 3 places up. efs 3002-07-04 */
for (sfb = 11; sfb >= 3; sfb--)
{
scalefac_IIP_buffer[3*sfb + 2] = scalefac_IIP_buffer[3*sfb - 1];
scalefac_IIP_buffer[3*sfb + 1] = scalefac_IIP_buffer[3*sfb - 2];
scalefac_IIP_buffer[3*sfb ] = scalefac_IIP_buffer[3*sfb - 3];
}
}
else
{ /* SHORT*/
for (sfb = 0; sfb < 12; sfb++)
{
for (window = 0; window < 3; window++)
{
scalefac->s[window][sfb] = scalefac_buffer[k];
k++;
}
}
}
scalefac->s[0][12] = 0;
scalefac->s[1][12] = 0;
scalefac->s[2][12] = 0;
}
else
{ /* LONG types 0,1,3 */
for (sfb = 0; sfb < 21; sfb++)
{
scalefac->l[sfb] = scalefac_buffer[sfb];
}
scalefac->l[21] = 0;
scalefac->l[22] = 0;
}
}
//====================================================================================================
//函数功能:获得"scale factor"
//函数参数:"si"表示旁信息,"gr"表示granule,"ch"表示声道,"info"表示头信息,"pMainData"表示输入流,
// "scalefac_IIP_buffer"表示辅助数组,均为输入参数
// "scalefac"表示量化因子,为输出参数
//====================================================================================================
void pvmp3_mpeg2_get_scale_factors(mp3ScaleFactors *scalefac,
mp3SideInfo *si,
int32 gr,
int32 ch,
mp3Header *info,
uint32 *scalefac_IIP_buffer,
tmp3Bits *pMainData)
{
//定义变量
int32 sfb;
int32 k = 0;
int32 window;
uint32 *scalefac_buffer = &scalefac_IIP_buffer[56];
granuleInfo *gr_info = &(si->ch[ch].gran[gr]);
//获得"scalefac_buffer"和"scalefac_IIP_buffer"信息
pvmp3_mpeg2_get_scale_data(si,
gr,
ch,
info,
(uint32 *)scalefac_buffer,
(uint32 *)scalefac_IIP_buffer,
pMainData);
//若"window_switching_flag"为1并且"block_type"为2
if (gr_info->window_switching_flag && (gr_info->block_type == 2))
{
//若"mixed_block_flag"为1,即为混合型
if (gr_info->mixed_block_flag)
{
//对"l[sfb]"赋值,其中"sfb"属于0-5
for (sfb = 0; sfb < 6; sfb++)
{
scalefac->l[sfb] = scalefac_buffer[sfb];
}
//对"s[window][sfb]"赋值,其中"window"属于0-2,"sfb"属于3-11
k = 6;
for (sfb = 3; sfb < 12; sfb++)
{
for (window = 0; window < 3; window++)
{
scalefac->s[window][sfb] = scalefac_buffer[k];
k++;
}
}
//调整非法位置
/* adjust position of "illegal position" information in scalefac_IIP_buffer[] */
/* in mixed blocks mode for short sfb, move them 3 places up. efs 3002-07-04 */
for (sfb = 11; sfb >= 3; sfb--)
{
scalefac_IIP_buffer[3*sfb + 2] = scalefac_IIP_buffer[3*sfb - 1];
scalefac_IIP_buffer[3*sfb + 1] = scalefac_IIP_buffer[3*sfb - 2];
scalefac_IIP_buffer[3*sfb ] = scalefac_IIP_buffer[3*sfb - 3];
}
}
//若为短窗框型
else
{
//对"s[window][sfb]"赋值,其中"window"属于0-2,"sfb"属于0-11
for (sfb = 0; sfb < 12; sfb++)
{
for (window = 0; window < 3; window++)
{
scalefac->s[window][sfb] = scalefac_buffer[k];
k++;
}
}
}
//为"s[window][12]"赋值为0,其中"window"属于0-2
scalefac->s[0][12] = 0;
scalefac->s[1][12] = 0;
scalefac->s[2][12] = 0;
}
//若为长窗框型的
else
{
//为"l[sfb]"赋值,其中"sfb"属于0-20
/* LONG types 0,1,3 */
for (sfb = 0; sfb < 21; sfb++)
{
scalefac->l[sfb] = scalefac_buffer[sfb];
}
//为"l[21]"和"l[22]"赋值为0
scalefac->l[21] = 0;
scalefac->l[22] = 0;
}
}
