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 1.26 2002/01/22 02:16:40 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);
404 ogg_uint32_t word=i<<(32-c->dec_firsttablen);
405 if(c->dec_firsttable[bitreverse(word)]==0){
406 while((lo+1)<n && c->codelist[lo+1]<=word)lo++;
407 while( hi<n && word>=(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[bitreverse(word)]=
419 0x80000000UL | (loval<<15) | hival;
428 vorbis_book_clear(c);
432 static float _dist(int el,float *ref, float *b,int step){
436 float val=(ref[i]-b[i*step]);
442 int _best(codebook *book, float *a, int step){
443 encode_aux_nearestmatch *nt=book->c->nearest_tree;
444 encode_aux_threshmatch *tt=book->c->thresh_tree;
445 encode_aux_pigeonhole *pt=book->c->pigeon_tree;
451 /* do we have a threshhold encode hint? */
454 /* find the quant val of each scalar */
455 for(k=0,o=step*(dim-1);k<dim;k++,o-=step){
457 /* linear search the quant list for now; it's small and although
458 with > ~8 entries, it would be faster to bisect, this would be
459 a misplaced optimization for now */
460 for(i=0;i<tt->threshvals-1;i++)
461 if(a[o]<tt->quantthresh[i])break;
463 index=(index*tt->quantvals)+tt->quantmap[i];
465 /* regular lattices are easy :-) */
466 if(book->c->lengthlist[index]>0) /* is this unused? If so, we'll
467 use a decision tree after all
472 /* do we have a pigeonhole encode hint? */
474 const static_codebook *c=book->c;
479 /* dealing with sequentialness is a pain in the ass */
484 for(k=0,o=0;k<dim;k++,o+=step){
485 pv=(int)((a[o]-qlast-pt->min)/pt->del);
486 if(pv<0 || pv>=pt->mapentries)break;
487 entry+=pt->pigeonmap[pv]*mul;
489 qlast+=pv*pt->del+pt->min;
492 for(k=0,o=step*(dim-1);k<dim;k++,o-=step){
493 int pv=(int)((a[o]-pt->min)/pt->del);
494 if(pv<0 || pv>=pt->mapentries)break;
495 entry=entry*pt->quantvals+pt->pigeonmap[pv];
499 /* must be within the pigeonholable range; if we quant outside (or
500 in an entry that we define no list for), brute force it */
501 if(k==dim && pt->fitlength[entry]){
502 /* search the abbreviated list */
503 long *list=pt->fitlist+pt->fitmap[entry];
504 for(i=0;i<pt->fitlength[entry];i++){
505 float this=_dist(dim,book->valuelist+list[i]*dim,a,step);
506 if(besti==-1 || this<best){
517 /* optimized using the decision tree */
520 float *p=book->valuelist+nt->p[ptr];
521 float *q=book->valuelist+nt->q[ptr];
523 for(k=0,o=0;k<dim;k++,o+=step)
524 c+=(p[k]-q[k])*(a[o]-(p[k]+q[k])*.5);
535 /* brute force it! */
537 const static_codebook *c=book->c;
540 float *e=book->valuelist;
541 for(i=0;i<book->entries;i++){
542 if(c->lengthlist[i]>0){
543 float this=_dist(dim,e,a,step);
544 if(besti==-1 || this<best){
552 /*if(savebest!=-1 && savebest!=besti){
553 fprintf(stderr,"brute force/pigeonhole disagreement:\n"
555 for(i=0;i<dim*step;i+=step)fprintf(stderr,"%g,",a[i]);
557 "pigeonhole (entry %d, err %g):",savebest,saverr);
558 for(i=0;i<dim;i++)fprintf(stderr,"%g,",
559 (book->valuelist+savebest*dim)[i]);
561 "bruteforce (entry %d, err %g):",besti,best);
562 for(i=0;i<dim;i++)fprintf(stderr,"%g,",
563 (book->valuelist+besti*dim)[i]);
564 fprintf(stderr,"\n");
570 /* returns the entry number and *modifies a* to the remainder value ********/
571 int vorbis_book_besterror(codebook *book,float *a,int step,int addmul){
572 int dim=book->dim,i,o;
573 int best=_best(book,a,step);
576 for(i=0,o=0;i<dim;i++,o+=step)
577 a[o]-=(book->valuelist+best*dim)[i];
580 for(i=0,o=0;i<dim;i++,o+=step){
581 float val=(book->valuelist+best*dim)[i];
593 long vorbis_book_codeword(codebook *book,int entry){
594 if(book->c) /* only use with encode; decode optimizations are
595 allowed to break this */
596 return book->codelist[entry];
600 long vorbis_book_codelen(codebook *book,int entry){
601 if(book->c) /* only use with encode; decode optimizations are
602 allowed to break this */
603 return book->c->lengthlist[entry];
609 /* Unit tests of the dequantizer; this stuff will be OK
610 cross-platform, I simply want to be sure that special mapping cases
611 actually work properly; a bug could go unnoticed for a while */
618 full, explicit mapping
625 static long full_quantlist1[]={0,1,2,3, 4,5,6,7, 8,3,6,1};
626 static long partial_quantlist1[]={0,7,2};
629 static_codebook test1={
637 static float *test1_result=NULL;
639 /* linear, full mapping, nonsequential */
640 static_codebook test2={
644 -533200896,1611661312,4,0,
648 static float test2_result[]={-3,-2,-1,0, 1,2,3,4, 5,0,3,-2};
650 /* linear, full mapping, sequential */
651 static_codebook test3={
655 -533200896,1611661312,4,1,
659 static float test3_result[]={-3,-5,-6,-6, 1,3,6,10, 5,5,8,6};
661 /* linear, algorithmic mapping, nonsequential */
662 static_codebook test4={
666 -533200896,1611661312,4,0,
670 static float test4_result[]={-3,-3,-3, 4,-3,-3, -1,-3,-3,
671 -3, 4,-3, 4, 4,-3, -1, 4,-3,
672 -3,-1,-3, 4,-1,-3, -1,-1,-3,
673 -3,-3, 4, 4,-3, 4, -1,-3, 4,
674 -3, 4, 4, 4, 4, 4, -1, 4, 4,
675 -3,-1, 4, 4,-1, 4, -1,-1, 4,
676 -3,-3,-1, 4,-3,-1, -1,-3,-1,
677 -3, 4,-1, 4, 4,-1, -1, 4,-1,
678 -3,-1,-1, 4,-1,-1, -1,-1,-1};
680 /* linear, algorithmic mapping, sequential */
681 static_codebook test5={
685 -533200896,1611661312,4,1,
689 static float test5_result[]={-3,-6,-9, 4, 1,-2, -1,-4,-7,
690 -3, 1,-2, 4, 8, 5, -1, 3, 0,
691 -3,-4,-7, 4, 3, 0, -1,-2,-5,
692 -3,-6,-2, 4, 1, 5, -1,-4, 0,
693 -3, 1, 5, 4, 8,12, -1, 3, 7,
694 -3,-4, 0, 4, 3, 7, -1,-2, 2,
695 -3,-6,-7, 4, 1, 0, -1,-4,-5,
696 -3, 1, 0, 4, 8, 7, -1, 3, 2,
697 -3,-4,-5, 4, 3, 2, -1,-2,-3};
699 void run_test(static_codebook *b,float *comp){
700 float *out=_book_unquantize(b,b->entries,NULL);
705 fprintf(stderr,"_book_unquantize incorrectly returned NULL\n");
709 for(i=0;i<b->entries*b->dim;i++)
710 if(fabs(out[i]-comp[i])>.0001){
711 fprintf(stderr,"disagreement in unquantized and reference data:\n"
712 "position %d, %g != %g\n",i,out[i],comp[i]);
718 fprintf(stderr,"_book_unquantize returned a value array: \n"
719 " correct result should have been NULL\n");
726 /* run the nine dequant tests, and compare to the hand-rolled results */
727 fprintf(stderr,"Dequant test 1... ");
728 run_test(&test1,test1_result);
729 fprintf(stderr,"OK\nDequant test 2... ");
730 run_test(&test2,test2_result);
731 fprintf(stderr,"OK\nDequant test 3... ");
732 run_test(&test3,test3_result);
733 fprintf(stderr,"OK\nDequant test 4... ");
734 run_test(&test4,test4_result);
735 fprintf(stderr,"OK\nDequant test 5... ");
736 run_test(&test5,test5_result);
737 fprintf(stderr,"OK\n\n");