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Diffstat (limited to 'src/libmpg123/layer1.c')
| -rw-r--r-- | src/libmpg123/layer1.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/src/libmpg123/layer1.c b/src/libmpg123/layer1.c new file mode 100644 index 0000000..0673d53 --- /dev/null +++ b/src/libmpg123/layer1.c @@ -0,0 +1,155 @@ +/* + layer1.c: the layer 1 decoder + + copyright 1995-2008 by the mpg123 project - free software under the terms of the LGPL 2.1 + see COPYING and AUTHORS files in distribution or http://mpg123.org + initially written by Michael Hipp + + may have a few bugs after last optimization ... +*/ + +#include "mpg123lib_intern.h" +#include "getbits.h" + +void I_step_one(unsigned int balloc[], unsigned int scale_index[2][SBLIMIT],mpg123_handle *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(fr, 4); + *ba++ = getbits(fr, 4); + } + for(i=jsbound;i<SBLIMIT;i++) *ba++ = getbits(fr, 4); + + ba = balloc; + + for(i=0;i<jsbound;i++) + { + if ((*ba++)) + *sca++ = getbits(fr, 6); + if ((*ba++)) + *sca++ = getbits(fr, 6); + } + for (i=jsbound;i<SBLIMIT;i++) + if((*ba++)) + { + *sca++ = getbits(fr, 6); + *sca++ = getbits(fr, 6); + } + } + else + { + int i; + for(i=0;i<SBLIMIT;i++) *ba++ = getbits(fr, 4); + + ba = balloc; + for (i=0;i<SBLIMIT;i++) + if ((*ba++)) + *sca++ = getbits(fr, 6); + } +} + +void I_step_two(real fraction[2][SBLIMIT],unsigned int balloc[2*SBLIMIT], unsigned int scale_index[2][SBLIMIT],mpg123_handle *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(fr, n+1); + + if((n = *ba++)) *sample++ = getbits(fr, n+1); + } + for(i=jsbound;i<SBLIMIT;i++) + if((n = *ba++)) + *sample++ = getbits(fr, n+1); + + ba = balloc; + for(sample=smpb,i=0;i<jsbound;i++) + { + if((n=*ba++)) + *f0++ = REAL_MUL_SCALE_LAYER12(DOUBLE_TO_REAL_15( ((-1)<<n) + (*sample++) + 1), fr->muls[n+1][*sca++]); + else *f0++ = DOUBLE_TO_REAL(0.0); + + if((n=*ba++)) + *f1++ = REAL_MUL_SCALE_LAYER12(DOUBLE_TO_REAL_15( ((-1)<<n) + (*sample++) + 1), fr->muls[n+1][*sca++]); + else *f1++ = DOUBLE_TO_REAL(0.0); + } + for(i=jsbound;i<SBLIMIT;i++) + { + if((n=*ba++)) + { + real samp = DOUBLE_TO_REAL_15( ((-1)<<n) + (*sample++) + 1); + *f0++ = REAL_MUL_SCALE_LAYER12(samp, fr->muls[n+1][*sca++]); + *f1++ = REAL_MUL_SCALE_LAYER12(samp, fr->muls[n+1][*sca++]); + } + else *f0++ = *f1++ = DOUBLE_TO_REAL(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(fr, n+1); + + ba = balloc; + for(sample=smpb,i=0;i<SBLIMIT;i++) + { + if((n=*ba++)) + *f0++ = REAL_MUL_SCALE_LAYER12(DOUBLE_TO_REAL_15( ((-1)<<n) + (*sample++) + 1), fr->muls[n+1][*sca++]); + else *f0++ = DOUBLE_TO_REAL(0.0); + } + for(i=fr->down_sample_sblimit;i<32;i++) + fraction[0][i] = DOUBLE_TO_REAL(0.0); + } +} + +int do_layer1(mpg123_handle *fr) +{ + int clip=0; + int i,stereo = fr->stereo; + unsigned int balloc[2*SBLIMIT]; + unsigned int scale_index[2][SBLIMIT]; + ALIGNED(16) 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 == SINGLE_MIX) /* I don't see mixing handled here */ + single = SINGLE_LEFT; + + I_step_one(balloc,scale_index,fr); + + for(i=0;i<SCALE_BLOCK;i++) + { + I_step_two(fraction,balloc,scale_index,fr); + + if(single != SINGLE_STEREO) + clip += (fr->synth_mono)(fraction[single], fr); + else + clip += (fr->synth_stereo)(fraction[0], fraction[1], fr); + } + + return clip; +} + + |