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serge |
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/* |
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layer1.c: the layer 1 decoder |
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Serge |
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copyright 1995-2009 by the mpg123 project - free software under the terms of the LGPL 2.1 |
| 1905 |
serge |
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see COPYING and AUTHORS files in distribution or http://mpg123.org |
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initially written by Michael Hipp |
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may have a few bugs after last optimization ... |
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*/ |
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#include "mpg123lib_intern.h" |
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#include "getbits.h" |
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Serge |
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static void I_step_one(unsigned int balloc[], unsigned int scale_index[2][SBLIMIT],mpg123_handle *fr) |
| 1905 |
serge |
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{ |
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unsigned int *ba=balloc; |
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unsigned int *sca = (unsigned int *) scale_index; |
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if(fr->stereo == 2) |
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{ |
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int i; |
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int jsbound = fr->jsbound; |
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for(i=0;i |
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{ |
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*ba++ = getbits(fr, 4); |
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*ba++ = getbits(fr, 4); |
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} |
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for(i=jsbound;i |
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ba = balloc; |
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for(i=0;i |
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{ |
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if ((*ba++)) |
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*sca++ = getbits(fr, 6); |
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if ((*ba++)) |
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*sca++ = getbits(fr, 6); |
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} |
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for (i=jsbound;i |
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if((*ba++)) |
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{ |
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*sca++ = getbits(fr, 6); |
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*sca++ = getbits(fr, 6); |
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} |
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} |
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else |
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{ |
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int i; |
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for(i=0;i |
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ba = balloc; |
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for (i=0;i |
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if ((*ba++)) |
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*sca++ = getbits(fr, 6); |
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} |
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} |
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Serge |
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static void I_step_two(real fraction[2][SBLIMIT],unsigned int balloc[2*SBLIMIT], unsigned int scale_index[2][SBLIMIT],mpg123_handle *fr) |
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serge |
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{ |
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int i,n; |
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int smpb[2*SBLIMIT]; /* values: 0-65535 */ |
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int *sample; |
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register unsigned int *ba; |
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register unsigned int *sca = (unsigned int *) scale_index; |
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if(fr->stereo == 2) |
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{ |
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int jsbound = fr->jsbound; |
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register real *f0 = fraction[0]; |
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register real *f1 = fraction[1]; |
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ba = balloc; |
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for(sample=smpb,i=0;i |
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{ |
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if((n = *ba++)) *sample++ = getbits(fr, n+1); |
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if((n = *ba++)) *sample++ = getbits(fr, n+1); |
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} |
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for(i=jsbound;i |
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if((n = *ba++)) |
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*sample++ = getbits(fr, n+1); |
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ba = balloc; |
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for(sample=smpb,i=0;i |
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{ |
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if((n=*ba++)) |
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*f0++ = REAL_MUL_SCALE_LAYER12(DOUBLE_TO_REAL_15( ((-1)<muls[n+1][*sca++]); |
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else *f0++ = DOUBLE_TO_REAL(0.0); |
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if((n=*ba++)) |
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*f1++ = REAL_MUL_SCALE_LAYER12(DOUBLE_TO_REAL_15( ((-1)<muls[n+1][*sca++]); |
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else *f1++ = DOUBLE_TO_REAL(0.0); |
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} |
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for(i=jsbound;i |
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{ |
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if((n=*ba++)) |
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{ |
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real samp = DOUBLE_TO_REAL_15( ((-1)< |
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*f0++ = REAL_MUL_SCALE_LAYER12(samp, fr->muls[n+1][*sca++]); |
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*f1++ = REAL_MUL_SCALE_LAYER12(samp, fr->muls[n+1][*sca++]); |
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} |
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else *f0++ = *f1++ = DOUBLE_TO_REAL(0.0); |
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} |
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for(i=fr->down_sample_sblimit;i<32;i++) |
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fraction[0][i] = fraction[1][i] = 0.0; |
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} |
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else |
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{ |
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register real *f0 = fraction[0]; |
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ba = balloc; |
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for(sample=smpb,i=0;i |
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if ((n = *ba++)) |
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*sample++ = getbits(fr, n+1); |
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ba = balloc; |
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for(sample=smpb,i=0;i |
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{ |
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if((n=*ba++)) |
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*f0++ = REAL_MUL_SCALE_LAYER12(DOUBLE_TO_REAL_15( ((-1)<muls[n+1][*sca++]); |
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else *f0++ = DOUBLE_TO_REAL(0.0); |
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} |
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for(i=fr->down_sample_sblimit;i<32;i++) |
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fraction[0][i] = DOUBLE_TO_REAL(0.0); |
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} |
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} |
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int do_layer1(mpg123_handle *fr) |
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{ |
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int clip=0; |
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int i,stereo = fr->stereo; |
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unsigned int balloc[2*SBLIMIT]; |
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unsigned int scale_index[2][SBLIMIT]; |
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Serge |
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real (*fraction)[SBLIMIT] = fr->layer1.fraction; /* fraction[2][SBLIMIT] */ |
| 1905 |
serge |
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int single = fr->single; |
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fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext<<2)+4 : 32; |
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if(stereo == 1 || single == SINGLE_MIX) /* I don't see mixing handled here */ |
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single = SINGLE_LEFT; |
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I_step_one(balloc,scale_index,fr); |
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for(i=0;i |
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{ |
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I_step_two(fraction,balloc,scale_index,fr); |
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if(single != SINGLE_STEREO) |
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clip += (fr->synth_mono)(fraction[single], fr); |
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else |
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clip += (fr->synth_stereo)(fraction[0], fraction[1], fr); |
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} |
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return clip; |
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} |
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