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 1994-2015 *
9 * by the Xiph.Org Foundation http://www.xiph.org/ *
11 ********************************************************************
13 function: basic shared codebook operations
16 ********************************************************************/
25 #include "vorbis/codec.h"
29 /**** pack/unpack helpers ******************************************/
31 int ov_ilog(ogg_uint32_t v){
33 for(ret=0;v;ret++)v>>=1;
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)+.001); //+epsilon
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(char *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 /* any underpopulated tree must be rejected. */
128 /* Single-entry codebooks are a retconned extension to the spec.
129 They have a single codeword '0' of length 1 that results in an
130 underpopulated tree. Shield that case from the underformed tree check. */
131 if(!(count==1 && marker[2]==2)){
133 if(marker[i] & (0xffffffffUL>>(32-i))){
139 /* bitreverse the words because our bitwise packer/unpacker is LSb
141 for(i=0,count=0;i<n;i++){
145 temp|=(r[count]>>j)&1;
158 /* there might be a straightforward one-line way to do the below
159 that's portable and totally safe against roundoff, but I haven't
160 thought of it. Therefore, we opt on the side of caution */
161 long _book_maptype1_quantvals(const static_codebook *b){
166 vals=floor(pow((float)b->entries,1.f/b->dim));
168 /* the above *should* be reliable, but we'll not assume that FP is
169 ever reliable when bitstream sync is at stake; verify via integer
170 means that vals really is the greatest value of dim for which
171 vals^b->bim <= b->entries */
172 /* treat the above as an initial guess */
180 for(i=0;i<b->dim;i++){
181 if(b->entries/vals<acc)break;
183 if(LONG_MAX/(vals+1)<acc1)acc1=LONG_MAX;
186 if(i>=b->dim && acc<=b->entries && acc1>b->entries){
189 if(i<b->dim || acc>b->entries){
198 /* unpack the quantized list of values for encode/decode ***********/
199 /* we need to deal with two map types: in map type 1, the values are
200 generated algorithmically (each column of the vector counts through
201 the values in the quant vector). in map type 2, all the values came
202 in in an explicit list. Both value lists must be unpacked */
203 float *_book_unquantize(const static_codebook *b,int n,int *sparsemap){
205 if(b->maptype==1 || b->maptype==2){
207 float mindel=_float32_unpack(b->q_min);
208 float delta=_float32_unpack(b->q_delta);
209 float *r=_ogg_calloc(n*b->dim,sizeof(*r));
211 /* maptype 1 and 2 both use a quantized value vector, but
215 /* most of the time, entries%dimensions == 0, but we need to be
216 well defined. We define that the possible vales at each
217 scalar is values == entries/dim. If entries%dim != 0, we'll
218 have 'too few' values (values*dim<entries), which means that
219 we'll have 'left over' entries; left over entries use zeroed
220 values (and are wasted). So don't generate codebooks like
222 quantvals=_book_maptype1_quantvals(b);
223 for(j=0;j<b->entries;j++){
224 if((sparsemap && b->lengthlist[j]) || !sparsemap){
227 for(k=0;k<b->dim;k++){
228 int index= (j/indexdiv)%quantvals;
229 float val=b->quantlist[index];
230 val=fabs(val)*delta+mindel+last;
231 if(b->q_sequencep)last=val;
233 r[sparsemap[count]*b->dim+k]=val;
235 r[count*b->dim+k]=val;
244 for(j=0;j<b->entries;j++){
245 if((sparsemap && b->lengthlist[j]) || !sparsemap){
248 for(k=0;k<b->dim;k++){
249 float val=b->quantlist[j*b->dim+k];
250 val=fabs(val)*delta+mindel+last;
251 if(b->q_sequencep)last=val;
253 r[sparsemap[count]*b->dim+k]=val;
255 r[count*b->dim+k]=val;
268 void vorbis_staticbook_destroy(static_codebook *b){
270 if(b->quantlist)_ogg_free(b->quantlist);
271 if(b->lengthlist)_ogg_free(b->lengthlist);
272 memset(b,0,sizeof(*b));
274 } /* otherwise, it is in static memory */
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);
299 c->quantvals=_book_maptype1_quantvals(s);
300 c->minval=(int)rint(_float32_unpack(s->q_min));
301 c->delta=(int)rint(_float32_unpack(s->q_delta));
306 static ogg_uint32_t bitreverse(ogg_uint32_t x){
307 x= ((x>>16)&0x0000ffffUL) | ((x<<16)&0xffff0000UL);
308 x= ((x>> 8)&0x00ff00ffUL) | ((x<< 8)&0xff00ff00UL);
309 x= ((x>> 4)&0x0f0f0f0fUL) | ((x<< 4)&0xf0f0f0f0UL);
310 x= ((x>> 2)&0x33333333UL) | ((x<< 2)&0xccccccccUL);
311 return((x>> 1)&0x55555555UL) | ((x<< 1)&0xaaaaaaaaUL);
314 static int sort32a(const void *a,const void *b){
315 return ( **(ogg_uint32_t **)a>**(ogg_uint32_t **)b)-
316 ( **(ogg_uint32_t **)a<**(ogg_uint32_t **)b);
319 /* decode codebook arrangement is more heavily optimized than encode */
320 int vorbis_book_init_decode(codebook *c,const static_codebook *s){
324 memset(c,0,sizeof(*c));
326 /* count actually used entries and find max length */
327 for(i=0;i<s->entries;i++)
328 if(s->lengthlist[i]>0)
331 c->entries=s->entries;
336 /* two different remappings go on here.
338 First, we collapse the likely sparse codebook down only to
339 actually represented values/words. This collapsing needs to be
340 indexed as map-valueless books are used to encode original entry
341 positions as integers.
343 Second, we reorder all vectors, including the entry index above,
344 by sorted bitreversed codeword to allow treeless decode. */
347 ogg_uint32_t *codes=_make_words(s->lengthlist,s->entries,c->used_entries);
348 ogg_uint32_t **codep=alloca(sizeof(*codep)*n);
350 if(codes==NULL)goto err_out;
353 codes[i]=bitreverse(codes[i]);
357 qsort(codep,n,sizeof(*codep),sort32a);
359 sortindex=alloca(n*sizeof(*sortindex));
360 c->codelist=_ogg_malloc(n*sizeof(*c->codelist));
361 /* the index is a reverse index */
363 int position=codep[i]-codes;
364 sortindex[position]=i;
368 c->codelist[sortindex[i]]=codes[i];
371 c->valuelist=_book_unquantize(s,n,sortindex);
372 c->dec_index=_ogg_malloc(n*sizeof(*c->dec_index));
374 for(n=0,i=0;i<s->entries;i++)
375 if(s->lengthlist[i]>0)
376 c->dec_index[sortindex[n++]]=i;
378 c->dec_codelengths=_ogg_malloc(n*sizeof(*c->dec_codelengths));
380 for(n=0,i=0;i<s->entries;i++)
381 if(s->lengthlist[i]>0){
382 c->dec_codelengths[sortindex[n++]]=s->lengthlist[i];
383 if(s->lengthlist[i]>c->dec_maxlength)
384 c->dec_maxlength=s->lengthlist[i];
387 if(n==1 && c->dec_maxlength==1){
388 /* special case the 'single entry codebook' with a single bit
389 fastpath table (that always returns entry 0 )in order to use
390 unmodified decode paths. */
391 c->dec_firsttablen=1;
392 c->dec_firsttable=_ogg_calloc(2,sizeof(*c->dec_firsttable));
393 c->dec_firsttable[0]=c->dec_firsttable[1]=1;
396 c->dec_firsttablen=ov_ilog(c->used_entries)-4; /* this is magic */
397 if(c->dec_firsttablen<5)c->dec_firsttablen=5;
398 if(c->dec_firsttablen>8)c->dec_firsttablen=8;
400 tabn=1<<c->dec_firsttablen;
401 c->dec_firsttable=_ogg_calloc(tabn,sizeof(*c->dec_firsttable));
404 if(c->dec_codelengths[i]<=c->dec_firsttablen){
405 ogg_uint32_t orig=bitreverse(c->codelist[i]);
406 for(j=0;j<(1<<(c->dec_firsttablen-c->dec_codelengths[i]));j++)
407 c->dec_firsttable[orig|(j<<c->dec_codelengths[i])]=i+1;
411 /* now fill in 'unused' entries in the firsttable with hi/lo search
412 hints for the non-direct-hits */
414 ogg_uint32_t mask=0xfffffffeUL<<(31-c->dec_firsttablen);
418 ogg_uint32_t word=i<<(32-c->dec_firsttablen);
419 if(c->dec_firsttable[bitreverse(word)]==0){
420 while((lo+1)<n && c->codelist[lo+1]<=word)lo++;
421 while( hi<n && word>=(c->codelist[hi]&mask))hi++;
423 /* we only actually have 15 bits per hint to play with here.
424 In order to overflow gracefully (nothing breaks, efficiency
425 just drops), encode as the difference from the extremes. */
427 unsigned long loval=lo;
428 unsigned long hival=n-hi;
430 if(loval>0x7fff)loval=0x7fff;
431 if(hival>0x7fff)hival=0x7fff;
432 c->dec_firsttable[bitreverse(word)]=
433 0x80000000UL | (loval<<15) | hival;
443 vorbis_book_clear(c);
447 long vorbis_book_codeword(codebook *book,int entry){
448 if(book->c) /* only use with encode; decode optimizations are
449 allowed to break this */
450 return book->codelist[entry];
454 long vorbis_book_codelen(codebook *book,int entry){
455 if(book->c) /* only use with encode; decode optimizations are
456 allowed to break this */
457 return book->c->lengthlist[entry];
463 /* Unit tests of the dequantizer; this stuff will be OK
464 cross-platform, I simply want to be sure that special mapping cases
465 actually work properly; a bug could go unnoticed for a while */
472 full, explicit mapping
479 static long full_quantlist1[]={0,1,2,3, 4,5,6,7, 8,3,6,1};
480 static long partial_quantlist1[]={0,7,2};
483 static_codebook test1={
491 static float *test1_result=NULL;
493 /* linear, full mapping, nonsequential */
494 static_codebook test2={
498 -533200896,1611661312,4,0,
502 static float test2_result[]={-3,-2,-1,0, 1,2,3,4, 5,0,3,-2};
504 /* linear, full mapping, sequential */
505 static_codebook test3={
509 -533200896,1611661312,4,1,
513 static float test3_result[]={-3,-5,-6,-6, 1,3,6,10, 5,5,8,6};
515 /* linear, algorithmic mapping, nonsequential */
516 static_codebook test4={
520 -533200896,1611661312,4,0,
524 static float test4_result[]={-3,-3,-3, 4,-3,-3, -1,-3,-3,
525 -3, 4,-3, 4, 4,-3, -1, 4,-3,
526 -3,-1,-3, 4,-1,-3, -1,-1,-3,
527 -3,-3, 4, 4,-3, 4, -1,-3, 4,
528 -3, 4, 4, 4, 4, 4, -1, 4, 4,
529 -3,-1, 4, 4,-1, 4, -1,-1, 4,
530 -3,-3,-1, 4,-3,-1, -1,-3,-1,
531 -3, 4,-1, 4, 4,-1, -1, 4,-1,
532 -3,-1,-1, 4,-1,-1, -1,-1,-1};
534 /* linear, algorithmic mapping, sequential */
535 static_codebook test5={
539 -533200896,1611661312,4,1,
543 static float test5_result[]={-3,-6,-9, 4, 1,-2, -1,-4,-7,
544 -3, 1,-2, 4, 8, 5, -1, 3, 0,
545 -3,-4,-7, 4, 3, 0, -1,-2,-5,
546 -3,-6,-2, 4, 1, 5, -1,-4, 0,
547 -3, 1, 5, 4, 8,12, -1, 3, 7,
548 -3,-4, 0, 4, 3, 7, -1,-2, 2,
549 -3,-6,-7, 4, 1, 0, -1,-4,-5,
550 -3, 1, 0, 4, 8, 7, -1, 3, 2,
551 -3,-4,-5, 4, 3, 2, -1,-2,-3};
553 void run_test(static_codebook *b,float *comp){
554 float *out=_book_unquantize(b,b->entries,NULL);
559 fprintf(stderr,"_book_unquantize incorrectly returned NULL\n");
563 for(i=0;i<b->entries*b->dim;i++)
564 if(fabs(out[i]-comp[i])>.0001){
565 fprintf(stderr,"disagreement in unquantized and reference data:\n"
566 "position %d, %g != %g\n",i,out[i],comp[i]);
572 fprintf(stderr,"_book_unquantize returned a value array: \n"
573 " correct result should have been NULL\n");
580 /* run the nine dequant tests, and compare to the hand-rolled results */
581 fprintf(stderr,"Dequant test 1... ");
582 run_test(&test1,test1_result);
583 fprintf(stderr,"OK\nDequant test 2... ");
584 run_test(&test2,test2_result);
585 fprintf(stderr,"OK\nDequant test 3... ");
586 run_test(&test3,test3_result);
587 fprintf(stderr,"OK\nDequant test 4... ");
588 run_test(&test4,test4_result);
589 fprintf(stderr,"OK\nDequant test 5... ");
590 run_test(&test5,test5_result);
591 fprintf(stderr,"OK\n\n");