| 0,0 → 1,151 |
|---|
| /* |
| layer1.c: the layer 1 decoder |
| |
| copyright 1995-2006 by the mpg123 project - free software under the terms of the LGPL 2.1 |
| see COPYING and AUTHORS files in distribution or http://mpg123.de |
| initially written by Michael Hipp |
| |
| may have a few bugs after last optimization ... |
| */ |
| |
| #include "mpg123.h" |
| |
| void I_step_one(unsigned int balloc[], unsigned int scale_index[2][SBLIMIT],struct frame *fr) |
| { |
| unsigned int *ba=balloc; |
| unsigned int *sca = (unsigned int *) scale_index; |
| |
| if(fr->stereo == 2) { |
| int i; |
| int jsbound = fr->jsbound; |
| for (i=0;i<jsbound;i++) { |
| *ba++ = getbits(4); |
| *ba++ = getbits(4); |
| } |
| for (i=jsbound;i<SBLIMIT;i++) |
| *ba++ = getbits(4); |
| |
| ba = balloc; |
| |
| for (i=0;i<jsbound;i++) { |
| if ((*ba++)) |
| *sca++ = getbits(6); |
| if ((*ba++)) |
| *sca++ = getbits(6); |
| } |
| for (i=jsbound;i<SBLIMIT;i++) |
| if ((*ba++)) { |
| *sca++ = getbits(6); |
| *sca++ = getbits(6); |
| } |
| } |
| else { |
| int i; |
| for (i=0;i<SBLIMIT;i++) |
| *ba++ = getbits(4); |
| ba = balloc; |
| for (i=0;i<SBLIMIT;i++) |
| if ((*ba++)) |
| *sca++ = getbits(6); |
| } |
| } |
| |
| void I_step_two(real fraction[2][SBLIMIT],unsigned int balloc[2*SBLIMIT], |
| unsigned int scale_index[2][SBLIMIT],struct frame *fr) |
| { |
| int i,n; |
| int smpb[2*SBLIMIT]; /* values: 0-65535 */ |
| int *sample; |
| register unsigned int *ba; |
| register unsigned int *sca = (unsigned int *) scale_index; |
| |
| if(fr->stereo == 2) { |
| int jsbound = fr->jsbound; |
| register real *f0 = fraction[0]; |
| register real *f1 = fraction[1]; |
| ba = balloc; |
| for (sample=smpb,i=0;i<jsbound;i++) { |
| if ((n = *ba++)) |
| *sample++ = getbits(n+1); |
| if ((n = *ba++)) |
| *sample++ = getbits(n+1); |
| } |
| for (i=jsbound;i<SBLIMIT;i++) |
| if ((n = *ba++)) |
| *sample++ = getbits(n+1); |
| |
| ba = balloc; |
| for (sample=smpb,i=0;i<jsbound;i++) { |
| if((n=*ba++)) |
| *f0++ = (real) ( ((-1)<<n) + (*sample++) + 1) * muls[n+1][*sca++]; |
| else |
| *f0++ = 0.0; |
| if((n=*ba++)) |
| *f1++ = (real) ( ((-1)<<n) + (*sample++) + 1) * muls[n+1][*sca++]; |
| else |
| *f1++ = 0.0; |
| } |
| for (i=jsbound;i<SBLIMIT;i++) { |
| if ((n=*ba++)) { |
| real samp = ( ((-1)<<n) + (*sample++) + 1); |
| *f0++ = samp * muls[n+1][*sca++]; |
| *f1++ = samp * muls[n+1][*sca++]; |
| } |
| else |
| *f0++ = *f1++ = 0.0; |
| } |
| for(i=fr->down_sample_sblimit;i<32;i++) |
| fraction[0][i] = fraction[1][i] = 0.0; |
| } |
| else { |
| register real *f0 = fraction[0]; |
| ba = balloc; |
| for (sample=smpb,i=0;i<SBLIMIT;i++) |
| if ((n = *ba++)) |
| *sample++ = getbits(n+1); |
| ba = balloc; |
| for (sample=smpb,i=0;i<SBLIMIT;i++) { |
| if((n=*ba++)) |
| *f0++ = (real) ( ((-1)<<n) + (*sample++) + 1) * muls[n+1][*sca++]; |
| else |
| *f0++ = 0.0; |
| } |
| for(i=fr->down_sample_sblimit;i<32;i++) |
| fraction[0][i] = 0.0; |
| } |
| } |
| |
| int do_layer1(struct frame *fr,byte *pcm_sample, int *pcm_point) |
| { |
| int clip=0; |
| int i,stereo = fr->stereo; |
| unsigned int balloc[2*SBLIMIT]; |
| unsigned int scale_index[2][SBLIMIT]; |
| real fraction[2][SBLIMIT]; |
| int single = fr->single; |
| |
| fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext<<2)+4 : 32; |
| |
| if(stereo == 1 || single == 3) |
| single = 0; |
| |
| I_step_one(balloc,scale_index,fr); |
| |
| for (i=0;i<SCALE_BLOCK;i++) |
| { |
| I_step_two(fraction,balloc,scale_index,fr); |
| |
| if(single >= 0) |
| { |
| clip += (fr->synth_mono)( (real *) fraction[single],pcm_sample,pcm_point); |
| } |
| else { |
| int p1=*pcm_point; |
| clip += (fr->synth)( (real *) fraction[0],0,pcm_sample,&p1); |
| clip += (fr->synth)( (real *) fraction[1],1,pcm_sample,pcm_point); |
| } |
| } |
| return clip; |
| } |
| |
| |