135 lines
5.0 KiB
C++
Executable File
135 lines
5.0 KiB
C++
Executable File
/* L3mdct */
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#include "types.h"
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#include "l3mdct.h"
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#include "l3subband.h"
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/* This is table B.9: coefficients for aliasing reduction */
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#define MDCT_CA(coef) (int)(coef / sqrt(1.0 + (coef * coef)) * 0x7fffffff)
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#define MDCT_CS(coef) (int)(1.0 / sqrt(1.0 + (coef * coef)) * 0x7fffffff)
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#define MDCT_CA0 MDCT_CA(-0.6)
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#define MDCT_CA1 MDCT_CA(-0.535)
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#define MDCT_CA2 MDCT_CA(-0.33)
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#define MDCT_CA3 MDCT_CA(-0.185)
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#define MDCT_CA4 MDCT_CA(-0.095)
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#define MDCT_CA5 MDCT_CA(-0.041)
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#define MDCT_CA6 MDCT_CA(-0.0142)
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#define MDCT_CA7 MDCT_CA(-0.0037)
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#define MDCT_CS0 MDCT_CS(-0.6)
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#define MDCT_CS1 MDCT_CS(-0.535)
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#define MDCT_CS2 MDCT_CS(-0.33)
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#define MDCT_CS3 MDCT_CS(-0.185)
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#define MDCT_CS4 MDCT_CS(-0.095)
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#define MDCT_CS5 MDCT_CS(-0.041)
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#define MDCT_CS6 MDCT_CS(-0.0142)
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#define MDCT_CS7 MDCT_CS(-0.0037)
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/*
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* shine_mdct_initialise:
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* -------------------
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*/
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void shine_mdct_initialise(shine_global_config *config) {
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int m,k;
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/* prepare the mdct coefficients */
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for(m=18; m--; )
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for(k=36; k--; )
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/* combine window and mdct coefficients into a single table */
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/* scale and convert to fixed point before storing */
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config->mdct.cos_l[m][k] = (int)(sin(PI36*(k+0.5))
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* cos((PI/72)*(2*k+19)*(2*m+1)) * 0x7fffffff);
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}
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/*
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* shine_mdct_sub:
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* ------------
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*/
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void shine_mdct_sub(shine_global_config *config, int stride) {
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/* note. we wish to access the array 'config->mdct_freq[2][2][576]' as
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* [2][2][32][18]. (32*18=576),
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*/
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int (*mdct_enc)[18];
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int ch,gr,band,j,k;
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int mdct_in[36];
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for(ch=config->wave.channels; ch--; )
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{
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for(gr=0; gr<config->mpeg.granules_per_frame; gr++)
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{
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/* set up pointer to the part of config->mdct_freq we're using */
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mdct_enc = (int (*)[18]) config->mdct_freq[ch][gr];
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/* polyphase filtering */
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for(k=0; k<18; k+=2)
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{
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shine_window_filter_subband(&config->buffer[ch], &config->l3_sb_sample[ch][gr+1][k ][0], ch, config, stride);
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shine_window_filter_subband(&config->buffer[ch], &config->l3_sb_sample[ch][gr+1][k+1][0], ch, config, stride);
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/* Compensate for inversion in the analysis filter
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* (every odd index of band AND k)
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*/
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for(band=1; band<32; band+=2)
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config->l3_sb_sample[ch][gr+1][k+1][band] *= -1;
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}
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/* Perform imdct of 18 previous subband samples + 18 current subband samples */
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for(band=0; band<32; band++)
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{
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for(k=18; k--; )
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{
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mdct_in[k ] = config->l3_sb_sample[ch][gr ][k][band];
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mdct_in[k+18] = config->l3_sb_sample[ch][gr+1][k][band];
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}
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/* Calculation of the MDCT
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* In the case of long blocks ( block_type 0,1,3 ) there are
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* 36 coefficients in the time domain and 18 in the frequency
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* domain.
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*/
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for(k=18; k--; )
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{
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int vm;
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#ifdef __BORLANDC__
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uint32_t vm_lo;
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#else
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uint32_t vm_lo __attribute__((unused));
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#endif
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asm_mul0(vm, vm_lo, mdct_in[35], config->mdct.cos_l[k][35]);
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for(j=35; j; j-=7) {
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asm_muladd(vm, vm_lo, mdct_in[j-1], config->mdct.cos_l[k][j-1]);
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asm_muladd(vm, vm_lo, mdct_in[j-2], config->mdct.cos_l[k][j-2]);
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asm_muladd(vm, vm_lo, mdct_in[j-3], config->mdct.cos_l[k][j-3]);
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asm_muladd(vm, vm_lo, mdct_in[j-4], config->mdct.cos_l[k][j-4]);
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asm_muladd(vm, vm_lo, mdct_in[j-5], config->mdct.cos_l[k][j-5]);
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asm_muladd(vm, vm_lo, mdct_in[j-6], config->mdct.cos_l[k][j-6]);
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asm_muladd(vm, vm_lo, mdct_in[j-7], config->mdct.cos_l[k][j-7]);
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}
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asm_mulz(vm, vm_lo);
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mdct_enc[band][k] = vm;
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}
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/* Perform aliasing reduction butterfly */
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asm ("#asm_cmuls:");
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if (band != 0)
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{
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asm_cmuls(mdct_enc[band][0], mdct_enc[band-1][17-0], mdct_enc[band][0], mdct_enc[band-1][17-0], MDCT_CS0, MDCT_CA0);
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asm_cmuls(mdct_enc[band][1], mdct_enc[band-1][17-1], mdct_enc[band][1], mdct_enc[band-1][17-1], MDCT_CS1, MDCT_CA1);
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asm_cmuls(mdct_enc[band][2], mdct_enc[band-1][17-2], mdct_enc[band][2], mdct_enc[band-1][17-2], MDCT_CS2, MDCT_CA2);
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asm_cmuls(mdct_enc[band][3], mdct_enc[band-1][17-3], mdct_enc[band][3], mdct_enc[band-1][17-3], MDCT_CS3, MDCT_CA3);
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asm_cmuls(mdct_enc[band][4], mdct_enc[band-1][17-4], mdct_enc[band][4], mdct_enc[band-1][17-4], MDCT_CS4, MDCT_CA4);
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asm_cmuls(mdct_enc[band][5], mdct_enc[band-1][17-5], mdct_enc[band][5], mdct_enc[band-1][17-5], MDCT_CS5, MDCT_CA5);
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asm_cmuls(mdct_enc[band][6], mdct_enc[band-1][17-6], mdct_enc[band][6], mdct_enc[band-1][17-6], MDCT_CS6, MDCT_CA6);
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asm_cmuls(mdct_enc[band][7], mdct_enc[band-1][17-7], mdct_enc[band][7], mdct_enc[band-1][17-7], MDCT_CS7, MDCT_CA7);
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}
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}
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}
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/* Save latest granule's subband samples to be used in the next mdct call */
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memcpy(config->l3_sb_sample[ch][0], config->l3_sb_sample[ch][config->mpeg.granules_per_frame], sizeof(config->l3_sb_sample[0][0]));
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}
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}
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