1 /********************************************************************
3 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. *
4 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
5 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
6 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
8 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002 *
9 * by the XIPHOPHORUS Company http://www.xiph.org/ *
11 ********************************************************************
13 function: basic shared codebook operations
14 last mod: $Id: sharedbook.c,v 1.25 2002/01/21 20:51:28 xiphmont Exp $
16 ********************************************************************/
23 #include "vorbis/codec.h"
27 /**** pack/unpack helpers ******************************************/
28 int _ilog(unsigned int v){
37 /* 32 bit float (not IEEE; nonnormalized mantissa +
38 biased exponent) : neeeeeee eeemmmmm mmmmmmmm mmmmmmmm
39 Why not IEEE? It's just not that important here. */
43 #define VQ_FEXP_BIAS 768 /* bias toward values smaller than 1. */
45 /* doesn't currently guard under/overflow */
46 long _float32_pack(float val){
54 exp= floor(log(val)/log(2.f));
55 mant=rint(ldexp(val,(VQ_FMAN-1)-exp));
56 exp=(exp+VQ_FEXP_BIAS)<<VQ_FMAN;
58 return(sign|exp|mant);
61 float _float32_unpack(long val){
62 double mant=val&0x1fffff;
63 int sign=val&0x80000000;
64 long exp =(val&0x7fe00000L)>>VQ_FMAN;
66 return(ldexp(mant,exp-(VQ_FMAN-1)-VQ_FEXP_BIAS));
69 /* given a list of word lengths, generate a list of codewords. Works
70 for length ordered or unordered, always assigns the lowest valued
71 codewords first. Extended to handle unused entries (length 0) */
72 ogg_uint32_t *_make_words(long *l,long n,long sparsecount){
74 ogg_uint32_t marker[33];
75 ogg_uint32_t *r=_ogg_malloc((sparsecount?sparsecount:n)*sizeof(*r));
76 memset(marker,0,sizeof(marker));
81 ogg_uint32_t entry=marker[length];
83 /* when we claim a node for an entry, we also claim the nodes
84 below it (pruning off the imagined tree that may have dangled
85 from it) as well as blocking the use of any nodes directly
89 if(length<32 && (entry>>length)){
90 /* error condition; the lengths must specify an overpopulated tree */
96 /* Look to see if the next shorter marker points to the node
97 above. if so, update it and repeat. */
99 for(j=length;j>0;j--){
102 /* have to jump branches */
106 marker[j]=marker[j-1]<<1;
107 break; /* invariant says next upper marker would already
108 have been moved if it was on the same path */
114 /* prune the tree; the implicit invariant says all the longer
115 markers were dangling from our just-taken node. Dangle them
116 from our *new* node. */
117 for(j=length+1;j<33;j++)
118 if((marker[j]>>1) == entry){
120 marker[j]=marker[j-1]<<1;
124 if(sparsecount==0)count++;
127 /* bitreverse the words because our bitwise packer/unpacker is LSb
129 for(i=0,count=0;i<n;i++){
133 temp|=(r[count]>>j)&1;
146 /* there might be a straightforward one-line way to do the below
147 that's portable and totally safe against roundoff, but I haven't
148 thought of it. Therefore, we opt on the side of caution */
149 long _book_maptype1_quantvals(const static_codebook *b){
150 long vals=floor(pow((float)b->entries,1.f/b->dim));
152 /* the above *should* be reliable, but we'll not assume that FP is
153 ever reliable when bitstream sync is at stake; verify via integer
154 means that vals really is the greatest value of dim for which
155 vals^b->bim <= b->entries */
156 /* treat the above as an initial guess */
161 for(i=0;i<b->dim;i++){
165 if(acc<=b->entries && acc1>b->entries){
177 /* unpack the quantized list of values for encode/decode ***********/
178 /* we need to deal with two map types: in map type 1, the values are
179 generated algorithmically (each column of the vector counts through
180 the values in the quant vector). in map type 2, all the values came
181 in in an explicit list. Both value lists must be unpacked */
182 float *_book_unquantize(const static_codebook *b,int n,int *sparsemap){
184 if(b->maptype==1 || b->maptype==2){
186 float mindel=_float32_unpack(b->q_min);
187 float delta=_float32_unpack(b->q_delta);
188 float *r=_ogg_calloc(n*b->dim,sizeof(*r));
190 /* maptype 1 and 2 both use a quantized value vector, but
194 /* most of the time, entries%dimensions == 0, but we need to be
195 well defined. We define that the possible vales at each
196 scalar is values == entries/dim. If entries%dim != 0, we'll
197 have 'too few' values (values*dim<entries), which means that
198 we'll have 'left over' entries; left over entries use zeroed
199 values (and are wasted). So don't generate codebooks like
201 quantvals=_book_maptype1_quantvals(b);
202 for(j=0;j<b->entries;j++){
203 if((sparsemap && b->lengthlist[j]) || !sparsemap){
206 for(k=0;k<b->dim;k++){
207 int index= (j/indexdiv)%quantvals;
208 float val=b->quantlist[index];
209 val=fabs(val)*delta+mindel+last;
210 if(b->q_sequencep)last=val;
212 r[sparsemap[count]*b->dim+k]=val;
214 r[count*b->dim+k]=val;
223 for(j=0;j<b->entries;j++){
224 if((sparsemap && b->lengthlist[j]) || !sparsemap){
227 for(k=0;k<b->dim;k++){
228 float val=b->quantlist[j*b->dim+k];
229 val=fabs(val)*delta+mindel+last;
230 if(b->q_sequencep)last=val;
232 r[sparsemap[count]*b->dim+k]=val;
234 r[count*b->dim+k]=val;
247 void vorbis_staticbook_clear(static_codebook *b){
249 if(b->quantlist)_ogg_free(b->quantlist);
250 if(b->lengthlist)_ogg_free(b->lengthlist);
252 _ogg_free(b->nearest_tree->ptr0);
253 _ogg_free(b->nearest_tree->ptr1);
254 _ogg_free(b->nearest_tree->p);
255 _ogg_free(b->nearest_tree->q);
256 memset(b->nearest_tree,0,sizeof(*b->nearest_tree));
257 _ogg_free(b->nearest_tree);
260 _ogg_free(b->thresh_tree->quantthresh);
261 _ogg_free(b->thresh_tree->quantmap);
262 memset(b->thresh_tree,0,sizeof(*b->thresh_tree));
263 _ogg_free(b->thresh_tree);
266 memset(b,0,sizeof(*b));
270 void vorbis_staticbook_destroy(static_codebook *b){
272 vorbis_staticbook_clear(b);
277 void vorbis_book_clear(codebook *b){
278 /* static book is not cleared; we're likely called on the lookup and
279 the static codebook belongs to the info struct */
280 if(b->valuelist)_ogg_free(b->valuelist);
281 if(b->codelist)_ogg_free(b->codelist);
283 if(b->dec_index)_ogg_free(b->dec_index);
284 if(b->dec_codelengths)_ogg_free(b->dec_codelengths);
285 if(b->dec_firsttable)_ogg_free(b->dec_firsttable);
287 memset(b,0,sizeof(*b));
290 int vorbis_book_init_encode(codebook *c,const static_codebook *s){
292 memset(c,0,sizeof(*c));
294 c->entries=s->entries;
295 c->used_entries=s->entries;
297 c->codelist=_make_words(s->lengthlist,s->entries,0);
298 c->valuelist=_book_unquantize(s,s->entries,NULL);
303 static ogg_uint32_t bitreverse(ogg_uint32_t x){
304 x= ((x>>16)&0x0000ffffUL) | ((x<<16)&0xffff0000UL);
305 x= ((x>> 8)&0x00ff00ffUL) | ((x<< 8)&0xff00ff00UL);
306 x= ((x>> 4)&0x0f0f0f0fUL) | ((x<< 4)&0xf0f0f0f0UL);
307 x= ((x>> 2)&0x33333333UL) | ((x<< 2)&0xccccccccUL);
308 return((x>> 1)&0x55555555UL) | ((x<< 1)&0xaaaaaaaaUL);
311 static int sort32a(const void *a,const void *b){
312 return ( (**(ogg_uint32_t **)a>**(ogg_uint32_t **)b)<<1)-1;
315 /* decode codebook arrangement is more heavily optimized than encode */
316 int vorbis_book_init_decode(codebook *c,const static_codebook *s){
319 memset(c,0,sizeof(*c));
321 /* count actually used entries */
322 for(i=0;i<s->entries;i++)
323 if(s->lengthlist[i]>0)
326 c->entries=s->entries;
330 /* two different remappings go on here.
332 First, we collapse the likely sparse codebook down only to
333 actually represented values/words. This collapsing needs to be
334 indexed as map-valueless books are used to encode original entry
335 positions as integers.
337 Second, we reorder all vectors, including the entry index above,
338 by sorted bitreversed codeword to allow treeless decode. */
342 ogg_uint32_t *codes=_make_words(s->lengthlist,s->entries,c->used_entries);
343 ogg_uint32_t **codep=alloca(sizeof(*codep)*n);
345 if(codes==NULL)goto err_out;
348 codes[i]=bitreverse(codes[i]);
352 qsort(codep,n,sizeof(*codep),sort32a);
354 sortindex=alloca(n*sizeof(*sortindex));
355 c->codelist=_ogg_malloc(n*sizeof(*c->codelist));
356 /* the index is a reverse index */
358 int position=codep[i]-codes;
359 sortindex[position]=i;
363 c->codelist[sortindex[i]]=codes[i];
367 c->valuelist=_book_unquantize(s,n,sortindex);
368 c->dec_index=_ogg_malloc(n*sizeof(*c->dec_index));
370 for(n=0,i=0;i<s->entries;i++)
371 if(s->lengthlist[i]>0)
372 c->dec_index[sortindex[n++]]=i;
374 c->dec_codelengths=_ogg_malloc(n*sizeof(*c->dec_codelengths));
375 for(n=0,i=0;i<s->entries;i++)
376 if(s->lengthlist[i]>0)
377 c->dec_codelengths[sortindex[n++]]=s->lengthlist[i];
379 c->dec_firsttablen=_ilog(c->used_entries)-4; /* this is magic */
380 if(c->dec_firsttablen<5)c->dec_firsttablen=5;
381 if(c->dec_firsttablen>8)c->dec_firsttablen=8;
383 tabn=1<<c->dec_firsttablen;
384 c->dec_firsttable=_ogg_calloc(tabn,sizeof(*c->dec_firsttable));
388 if(c->dec_maxlength<c->dec_codelengths[i])
389 c->dec_maxlength=c->dec_codelengths[i];
390 if(c->dec_codelengths[i]<=c->dec_firsttablen){
391 ogg_uint32_t orig=bitreverse(c->codelist[i]);
392 for(j=0;j<(1<<(c->dec_firsttablen-c->dec_codelengths[i]));j++)
393 c->dec_firsttable[orig|(j<<c->dec_codelengths[i])]=i+1;
397 /* now fill in 'unused' entries in the firsttable with hi/lo search
398 hints for the non-direct-hits */
400 ogg_uint32_t mask=0xfffffffeUL<<(31-c->dec_firsttablen);
403 if(c->dec_firsttable[i]==0){
404 ogg_uint32_t testword=bitreverse(i);
406 while((lo+1)<n && c->codelist[lo+1]<=testword)lo++;
407 while( hi<n && testword>=(c->codelist[hi]&mask))hi++;
409 /* we only actually have 15 bits per hint to play with here.
410 In order to overflow gracefully (nothing breaks, efficiency
411 just drops), encode as the difference from the extremes. */
413 unsigned long loval=lo;
414 unsigned long hival=n-hi;
416 if(loval>0x7fff)loval=0x7fff;
417 if(hival>0x7fff)hival=0x7fff;
418 c->dec_firsttable[i]=0x80000000UL | (loval<<15) | hival;
427 vorbis_book_clear(c);
431 static float _dist(int el,float *ref, float *b,int step){
435 float val=(ref[i]-b[i*step]);
441 int _best(codebook *book, float *a, int step){
442 encode_aux_nearestmatch *nt=book->c->nearest_tree;
443 encode_aux_threshmatch *tt=book->c->thresh_tree;
444 encode_aux_pigeonhole *pt=book->c->pigeon_tree;
450 /* do we have a threshhold encode hint? */
453 /* find the quant val of each scalar */
454 for(k=0,o=step*(dim-1);k<dim;k++,o-=step){
456 /* linear search the quant list for now; it's small and although
457 with > ~8 entries, it would be faster to bisect, this would be
458 a misplaced optimization for now */
459 for(i=0;i<tt->threshvals-1;i++)
460 if(a[o]<tt->quantthresh[i])break;
462 index=(index*tt->quantvals)+tt->quantmap[i];
464 /* regular lattices are easy :-) */
465 if(book->c->lengthlist[index]>0) /* is this unused? If so, we'll
466 use a decision tree after all
471 /* do we have a pigeonhole encode hint? */
473 const static_codebook *c=book->c;
478 /* dealing with sequentialness is a pain in the ass */
483 for(k=0,o=0;k<dim;k++,o+=step){
484 pv=(int)((a[o]-qlast-pt->min)/pt->del);
485 if(pv<0 || pv>=pt->mapentries)break;
486 entry+=pt->pigeonmap[pv]*mul;
488 qlast+=pv*pt->del+pt->min;
491 for(k=0,o=step*(dim-1);k<dim;k++,o-=step){
492 int pv=(int)((a[o]-pt->min)/pt->del);
493 if(pv<0 || pv>=pt->mapentries)break;
494 entry=entry*pt->quantvals+pt->pigeonmap[pv];
498 /* must be within the pigeonholable range; if we quant outside (or
499 in an entry that we define no list for), brute force it */
500 if(k==dim && pt->fitlength[entry]){
501 /* search the abbreviated list */
502 long *list=pt->fitlist+pt->fitmap[entry];
503 for(i=0;i<pt->fitlength[entry];i++){
504 float this=_dist(dim,book->valuelist+list[i]*dim,a,step);
505 if(besti==-1 || this<best){
516 /* optimized using the decision tree */
519 float *p=book->valuelist+nt->p[ptr];
520 float *q=book->valuelist+nt->q[ptr];
522 for(k=0,o=0;k<dim;k++,o+=step)
523 c+=(p[k]-q[k])*(a[o]-(p[k]+q[k])*.5);
534 /* brute force it! */
536 const static_codebook *c=book->c;
539 float *e=book->valuelist;
540 for(i=0;i<book->entries;i++){
541 if(c->lengthlist[i]>0){
542 float this=_dist(dim,e,a,step);
543 if(besti==-1 || this<best){
551 /*if(savebest!=-1 && savebest!=besti){
552 fprintf(stderr,"brute force/pigeonhole disagreement:\n"
554 for(i=0;i<dim*step;i+=step)fprintf(stderr,"%g,",a[i]);
556 "pigeonhole (entry %d, err %g):",savebest,saverr);
557 for(i=0;i<dim;i++)fprintf(stderr,"%g,",
558 (book->valuelist+savebest*dim)[i]);
560 "bruteforce (entry %d, err %g):",besti,best);
561 for(i=0;i<dim;i++)fprintf(stderr,"%g,",
562 (book->valuelist+besti*dim)[i]);
563 fprintf(stderr,"\n");
569 /* returns the entry number and *modifies a* to the remainder value ********/
570 int vorbis_book_besterror(codebook *book,float *a,int step,int addmul){
571 int dim=book->dim,i,o;
572 int best=_best(book,a,step);
575 for(i=0,o=0;i<dim;i++,o+=step)
576 a[o]-=(book->valuelist+best*dim)[i];
579 for(i=0,o=0;i<dim;i++,o+=step){
580 float val=(book->valuelist+best*dim)[i];
592 long vorbis_book_codeword(codebook *book,int entry){
593 if(book->c) /* only use with encode; decode optimizations are
594 allowed to break this */
595 return book->codelist[entry];
599 long vorbis_book_codelen(codebook *book,int entry){
600 if(book->c) /* only use with encode; decode optimizations are
601 allowed to break this */
602 return book->c->lengthlist[entry];
608 /* Unit tests of the dequantizer; this stuff will be OK
609 cross-platform, I simply want to be sure that special mapping cases
610 actually work properly; a bug could go unnoticed for a while */
617 full, explicit mapping
624 static long full_quantlist1[]={0,1,2,3, 4,5,6,7, 8,3,6,1};
625 static long partial_quantlist1[]={0,7,2};
628 static_codebook test1={
636 static float *test1_result=NULL;
638 /* linear, full mapping, nonsequential */
639 static_codebook test2={
643 -533200896,1611661312,4,0,
647 static float test2_result[]={-3,-2,-1,0, 1,2,3,4, 5,0,3,-2};
649 /* linear, full mapping, sequential */
650 static_codebook test3={
654 -533200896,1611661312,4,1,
658 static float test3_result[]={-3,-5,-6,-6, 1,3,6,10, 5,5,8,6};
660 /* linear, algorithmic mapping, nonsequential */
661 static_codebook test4={
665 -533200896,1611661312,4,0,
669 static float test4_result[]={-3,-3,-3, 4,-3,-3, -1,-3,-3,
670 -3, 4,-3, 4, 4,-3, -1, 4,-3,
671 -3,-1,-3, 4,-1,-3, -1,-1,-3,
672 -3,-3, 4, 4,-3, 4, -1,-3, 4,
673 -3, 4, 4, 4, 4, 4, -1, 4, 4,
674 -3,-1, 4, 4,-1, 4, -1,-1, 4,
675 -3,-3,-1, 4,-3,-1, -1,-3,-1,
676 -3, 4,-1, 4, 4,-1, -1, 4,-1,
677 -3,-1,-1, 4,-1,-1, -1,-1,-1};
679 /* linear, algorithmic mapping, sequential */
680 static_codebook test5={
684 -533200896,1611661312,4,1,
688 static float test5_result[]={-3,-6,-9, 4, 1,-2, -1,-4,-7,
689 -3, 1,-2, 4, 8, 5, -1, 3, 0,
690 -3,-4,-7, 4, 3, 0, -1,-2,-5,
691 -3,-6,-2, 4, 1, 5, -1,-4, 0,
692 -3, 1, 5, 4, 8,12, -1, 3, 7,
693 -3,-4, 0, 4, 3, 7, -1,-2, 2,
694 -3,-6,-7, 4, 1, 0, -1,-4,-5,
695 -3, 1, 0, 4, 8, 7, -1, 3, 2,
696 -3,-4,-5, 4, 3, 2, -1,-2,-3};
698 void run_test(static_codebook *b,float *comp){
699 float *out=_book_unquantize(b,b->entries,NULL);
704 fprintf(stderr,"_book_unquantize incorrectly returned NULL\n");
708 for(i=0;i<b->entries*b->dim;i++)
709 if(fabs(out[i]-comp[i])>.0001){
710 fprintf(stderr,"disagreement in unquantized and reference data:\n"
711 "position %d, %g != %g\n",i,out[i],comp[i]);
717 fprintf(stderr,"_book_unquantize returned a value array: \n"
718 " correct result should have been NULL\n");
725 /* run the nine dequant tests, and compare to the hand-rolled results */
726 fprintf(stderr,"Dequant test 1... ");
727 run_test(&test1,test1_result);
728 fprintf(stderr,"OK\nDequant test 2... ");
729 run_test(&test2,test2_result);
730 fprintf(stderr,"OK\nDequant test 3... ");
731 run_test(&test3,test3_result);
732 fprintf(stderr,"OK\nDequant test 4... ");
733 run_test(&test4,test4_result);
734 fprintf(stderr,"OK\nDequant test 5... ");
735 run_test(&test5,test5_result);
736 fprintf(stderr,"OK\n\n");