+++ /dev/null
-/*
- layer1.c: the layer 1 decoder
-
- copyright 1995-2009 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"
-#include "debug.h"
-
-/*
- Allocation value is not allowed to be 15. Initially, libmad showed me the
- error that mpg123 used to ignore. Then, I found a quote on that in
- Shlien, S. (1994): Guide to MPEG-1 Audio Standard.
- IEEE Transactions on Broadcasting 40, 4
-
- "To avoid conflicts with the synchronization code, code '1111' is defined
- to be illegal."
-*/
-static int check_balloc(mpg123_handle *fr, unsigned int *balloc, unsigned int *end)
-{
- unsigned int *ba;
- for(ba=balloc; ba != end; ++ba)
- if(*ba == 15)
- {
- if(NOQUIET) error("Illegal bit allocation value.");
- return -1;
- }
-
- return 0;
-}
-
-static int 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);
-
- if(check_balloc(fr, balloc, ba)) return -1;
-
- 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);
-
- if(check_balloc(fr, balloc, ba)) return -1;
-
- ba = balloc;
- for (i=0;i<SBLIMIT;i++)
- if ((*ba++))
- *sca++ = getbits(fr, 6);
- }
-
- return 0;
-}
-
-static 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];
- real (*fraction)[SBLIMIT] = fr->layer1.fraction; /* 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;
-
- if(I_step_one(balloc,scale_index,fr))
- {
- if(NOQUIET) error("Aborting layer I decoding after step one.\n");
- return clip;
- }
-
- 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;
-}
-
-
projects / reactos.git / blobdiff