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 1994-2001 *
9 * by the XIPHOPHORUS Company http://www.xiph.org/ *
11 ********************************************************************
13 function: basic shared codebook operations
14 last mod: $Id: sharedbook.c,v 1.22 2001/12/21 14:52:36 segher 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 long *_make_words(long *l,long n){
75 long *r=_ogg_malloc(n*sizeof(*r));
76 memset(marker,0,sizeof(marker));
81 long 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;
126 /* bitreverse the words because our bitwise packer/unpacker is LSb
140 /* build the decode helper tree from the codewords */
141 decode_aux *_make_decode_tree(codebook *c){
142 const static_codebook *s=c->c;
144 decode_aux *t=_ogg_malloc(sizeof(*t));
145 long *ptr0=t->ptr0=_ogg_calloc(c->entries*2,sizeof(*ptr0));
146 long *ptr1=t->ptr1=_ogg_calloc(c->entries*2,sizeof(*ptr1));
147 long *codelist=_make_words(s->lengthlist,s->entries);
149 if(codelist==NULL)return(NULL);
152 for(i=0;i<c->entries;i++){
153 if(s->lengthlist[i]>0){
155 for(j=0;j<s->lengthlist[i]-1;j++){
156 int bit=(codelist[i]>>j)&1;
167 if(!((codelist[i]>>j)&1))
175 t->tabn = _ilog(c->entries)-4; /* this is magic */
176 if(t->tabn<5)t->tabn=5;
178 t->tab = _ogg_malloc(n*sizeof(*t->tab));
179 t->tabl = _ogg_malloc(n*sizeof(*t->tabl));
180 for (i = 0; i < n; i++) {
182 for (j = 0; j < t->tabn && (p > 0 || j == 0); j++) {
188 /* now j == length, and p == -code */
196 /* there might be a straightforward one-line way to do the below
197 that's portable and totally safe against roundoff, but I haven't
198 thought of it. Therefore, we opt on the side of caution */
199 long _book_maptype1_quantvals(const static_codebook *b){
200 long vals=floor(pow((float)b->entries,1.f/b->dim));
202 /* the above *should* be reliable, but we'll not assume that FP is
203 ever reliable when bitstream sync is at stake; verify via integer
204 means that vals really is the greatest value of dim for which
205 vals^b->bim <= b->entries */
206 /* treat the above as an initial guess */
211 for(i=0;i<b->dim;i++){
215 if(acc<=b->entries && acc1>b->entries){
227 /* unpack the quantized list of values for encode/decode ***********/
228 /* we need to deal with two map types: in map type 1, the values are
229 generated algorithmically (each column of the vector counts through
230 the values in the quant vector). in map type 2, all the values came
231 in in an explicit list. Both value lists must be unpacked */
232 float *_book_unquantize(const static_codebook *b){
234 if(b->maptype==1 || b->maptype==2){
236 float mindel=_float32_unpack(b->q_min);
237 float delta=_float32_unpack(b->q_delta);
238 float *r=_ogg_calloc(b->entries*b->dim,sizeof(*r));
240 /* maptype 1 and 2 both use a quantized value vector, but
244 /* most of the time, entries%dimensions == 0, but we need to be
245 well defined. We define that the possible vales at each
246 scalar is values == entries/dim. If entries%dim != 0, we'll
247 have 'too few' values (values*dim<entries), which means that
248 we'll have 'left over' entries; left over entries use zeroed
249 values (and are wasted). So don't generate codebooks like
251 quantvals=_book_maptype1_quantvals(b);
252 for(j=0;j<b->entries;j++){
255 for(k=0;k<b->dim;k++){
256 int index= (j/indexdiv)%quantvals;
257 float val=b->quantlist[index];
258 val=fabs(val)*delta+mindel+last;
259 if(b->q_sequencep)last=val;
266 for(j=0;j<b->entries;j++){
268 for(k=0;k<b->dim;k++){
269 float val=b->quantlist[j*b->dim+k];
270 val=fabs(val)*delta+mindel+last;
271 if(b->q_sequencep)last=val;
283 void vorbis_staticbook_clear(static_codebook *b){
285 if(b->quantlist)_ogg_free(b->quantlist);
286 if(b->lengthlist)_ogg_free(b->lengthlist);
288 _ogg_free(b->nearest_tree->ptr0);
289 _ogg_free(b->nearest_tree->ptr1);
290 _ogg_free(b->nearest_tree->p);
291 _ogg_free(b->nearest_tree->q);
292 memset(b->nearest_tree,0,sizeof(*b->nearest_tree));
293 _ogg_free(b->nearest_tree);
296 _ogg_free(b->thresh_tree->quantthresh);
297 _ogg_free(b->thresh_tree->quantmap);
298 memset(b->thresh_tree,0,sizeof(*b->thresh_tree));
299 _ogg_free(b->thresh_tree);
302 memset(b,0,sizeof(*b));
306 void vorbis_staticbook_destroy(static_codebook *b){
308 vorbis_staticbook_clear(b);
313 void vorbis_book_clear(codebook *b){
314 /* static book is not cleared; we're likely called on the lookup and
315 the static codebook belongs to the info struct */
317 _ogg_free(b->decode_tree->tab);
318 _ogg_free(b->decode_tree->tabl);
320 _ogg_free(b->decode_tree->ptr0);
321 _ogg_free(b->decode_tree->ptr1);
322 memset(b->decode_tree,0,sizeof(*b->decode_tree));
323 _ogg_free(b->decode_tree);
325 if(b->valuelist)_ogg_free(b->valuelist);
326 if(b->codelist)_ogg_free(b->codelist);
327 memset(b,0,sizeof(*b));
330 int vorbis_book_init_encode(codebook *c,const static_codebook *s){
332 memset(c,0,sizeof(*c));
334 c->entries=s->entries;
336 c->codelist=_make_words(s->lengthlist,s->entries);
337 c->valuelist=_book_unquantize(s);
339 /* set the 'zero entry' */
342 for(j=0;j<s->entries;j++){
344 for(k=0;k<s->dim;k++){
345 if(fabs(c->valuelist[j*s->dim+k])>1e-12f){
358 int vorbis_book_init_decode(codebook *c,const static_codebook *s){
359 memset(c,0,sizeof(*c));
361 c->entries=s->entries;
363 c->valuelist=_book_unquantize(s);
364 c->decode_tree=_make_decode_tree(c);
365 if(c->decode_tree==NULL)goto err_out;
368 vorbis_book_clear(c);
372 static float _dist(int el,float *ref, float *b,int step){
376 float val=(ref[i]-b[i*step]);
382 int _best(codebook *book, float *a, int step){
383 encode_aux_nearestmatch *nt=book->c->nearest_tree;
384 encode_aux_threshmatch *tt=book->c->thresh_tree;
385 encode_aux_pigeonhole *pt=book->c->pigeon_tree;
391 /* do we have a threshhold encode hint? */
394 /* find the quant val of each scalar */
395 for(k=0,o=step*(dim-1);k<dim;k++,o-=step){
397 /* linear search the quant list for now; it's small and although
398 with > ~8 entries, it would be faster to bisect, this would be
399 a misplaced optimization for now */
400 for(i=0;i<tt->threshvals-1;i++)
401 if(a[o]<tt->quantthresh[i])break;
403 index=(index*tt->quantvals)+tt->quantmap[i];
405 /* regular lattices are easy :-) */
406 if(book->c->lengthlist[index]>0) /* is this unused? If so, we'll
407 use a decision tree after all
412 /* do we have a pigeonhole encode hint? */
414 const static_codebook *c=book->c;
419 /* dealing with sequentialness is a pain in the ass */
424 for(k=0,o=0;k<dim;k++,o+=step){
425 pv=(int)((a[o]-qlast-pt->min)/pt->del);
426 if(pv<0 || pv>=pt->mapentries)break;
427 entry+=pt->pigeonmap[pv]*mul;
429 qlast+=pv*pt->del+pt->min;
432 for(k=0,o=step*(dim-1);k<dim;k++,o-=step){
433 int pv=(int)((a[o]-pt->min)/pt->del);
434 if(pv<0 || pv>=pt->mapentries)break;
435 entry=entry*pt->quantvals+pt->pigeonmap[pv];
439 /* must be within the pigeonholable range; if we quant outside (or
440 in an entry that we define no list for), brute force it */
441 if(k==dim && pt->fitlength[entry]){
442 /* search the abbreviated list */
443 long *list=pt->fitlist+pt->fitmap[entry];
444 for(i=0;i<pt->fitlength[entry];i++){
445 float this=_dist(dim,book->valuelist+list[i]*dim,a,step);
446 if(besti==-1 || this<best){
457 /* optimized using the decision tree */
460 float *p=book->valuelist+nt->p[ptr];
461 float *q=book->valuelist+nt->q[ptr];
463 for(k=0,o=0;k<dim;k++,o+=step)
464 c+=(p[k]-q[k])*(a[o]-(p[k]+q[k])*.5);
475 /* brute force it! */
477 const static_codebook *c=book->c;
480 float *e=book->valuelist;
481 for(i=0;i<book->entries;i++){
482 if(c->lengthlist[i]>0){
483 float this=_dist(dim,e,a,step);
484 if(besti==-1 || this<best){
492 /*if(savebest!=-1 && savebest!=besti){
493 fprintf(stderr,"brute force/pigeonhole disagreement:\n"
495 for(i=0;i<dim*step;i+=step)fprintf(stderr,"%g,",a[i]);
497 "pigeonhole (entry %d, err %g):",savebest,saverr);
498 for(i=0;i<dim;i++)fprintf(stderr,"%g,",
499 (book->valuelist+savebest*dim)[i]);
501 "bruteforce (entry %d, err %g):",besti,best);
502 for(i=0;i<dim;i++)fprintf(stderr,"%g,",
503 (book->valuelist+besti*dim)[i]);
504 fprintf(stderr,"\n");
510 /* returns the entry number and *modifies a* to the remainder value ********/
511 int vorbis_book_besterror(codebook *book,float *a,int step,int addmul){
512 int dim=book->dim,i,o;
513 int best=_best(book,a,step);
516 for(i=0,o=0;i<dim;i++,o+=step)
517 a[o]-=(book->valuelist+best*dim)[i];
520 for(i=0,o=0;i<dim;i++,o+=step){
521 float val=(book->valuelist+best*dim)[i];
533 long vorbis_book_codeword(codebook *book,int entry){
534 return book->codelist[entry];
537 long vorbis_book_codelen(codebook *book,int entry){
538 return book->c->lengthlist[entry];
543 /* Unit tests of the dequantizer; this stuff will be OK
544 cross-platform, I simply want to be sure that special mapping cases
545 actually work properly; a bug could go unnoticed for a while */
552 full, explicit mapping
559 static long full_quantlist1[]={0,1,2,3, 4,5,6,7, 8,3,6,1};
560 static long partial_quantlist1[]={0,7,2};
563 static_codebook test1={
571 static float *test1_result=NULL;
573 /* linear, full mapping, nonsequential */
574 static_codebook test2={
578 -533200896,1611661312,4,0,
582 static float test2_result[]={-3,-2,-1,0, 1,2,3,4, 5,0,3,-2};
584 /* linear, full mapping, sequential */
585 static_codebook test3={
589 -533200896,1611661312,4,1,
593 static float test3_result[]={-3,-5,-6,-6, 1,3,6,10, 5,5,8,6};
595 /* linear, algorithmic mapping, nonsequential */
596 static_codebook test4={
600 -533200896,1611661312,4,0,
604 static float test4_result[]={-3,-3,-3, 4,-3,-3, -1,-3,-3,
605 -3, 4,-3, 4, 4,-3, -1, 4,-3,
606 -3,-1,-3, 4,-1,-3, -1,-1,-3,
607 -3,-3, 4, 4,-3, 4, -1,-3, 4,
608 -3, 4, 4, 4, 4, 4, -1, 4, 4,
609 -3,-1, 4, 4,-1, 4, -1,-1, 4,
610 -3,-3,-1, 4,-3,-1, -1,-3,-1,
611 -3, 4,-1, 4, 4,-1, -1, 4,-1,
612 -3,-1,-1, 4,-1,-1, -1,-1,-1};
614 /* linear, algorithmic mapping, sequential */
615 static_codebook test5={
619 -533200896,1611661312,4,1,
623 static float test5_result[]={-3,-6,-9, 4, 1,-2, -1,-4,-7,
624 -3, 1,-2, 4, 8, 5, -1, 3, 0,
625 -3,-4,-7, 4, 3, 0, -1,-2,-5,
626 -3,-6,-2, 4, 1, 5, -1,-4, 0,
627 -3, 1, 5, 4, 8,12, -1, 3, 7,
628 -3,-4, 0, 4, 3, 7, -1,-2, 2,
629 -3,-6,-7, 4, 1, 0, -1,-4,-5,
630 -3, 1, 0, 4, 8, 7, -1, 3, 2,
631 -3,-4,-5, 4, 3, 2, -1,-2,-3};
633 void run_test(static_codebook *b,float *comp){
634 float *out=_book_unquantize(b);
639 fprintf(stderr,"_book_unquantize incorrectly returned NULL\n");
643 for(i=0;i<b->entries*b->dim;i++)
644 if(fabs(out[i]-comp[i])>.0001){
645 fprintf(stderr,"disagreement in unquantized and reference data:\n"
646 "position %d, %g != %g\n",i,out[i],comp[i]);
652 fprintf(stderr,"_book_unquantize returned a value array: \n"
653 " correct result should have been NULL\n");
660 /* run the nine dequant tests, and compare to the hand-rolled results */
661 fprintf(stderr,"Dequant test 1... ");
662 run_test(&test1,test1_result);
663 fprintf(stderr,"OK\nDequant test 2... ");
664 run_test(&test2,test2_result);
665 fprintf(stderr,"OK\nDequant test 3... ");
666 run_test(&test3,test3_result);
667 fprintf(stderr,"OK\nDequant test 4... ");
668 run_test(&test4,test4_result);
669 fprintf(stderr,"OK\nDequant test 5... ");
670 run_test(&test5,test5_result);
671 fprintf(stderr,"OK\n\n");