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 https://xiph.org/ *
11 ********************************************************************
13 function: basic shared codebook operations
15 ********************************************************************/
24 #include "vorbis/codec.h"
28 /**** pack/unpack helpers ******************************************/
30 int ov_ilog(ogg_uint32_t v){
32 for(ret=0;v;ret++)v>>=1;
36 /* 32 bit float (not IEEE; nonnormalized mantissa +
37 biased exponent) : neeeeeee eeemmmmm mmmmmmmm mmmmmmmm
38 Why not IEEE? It's just not that important here. */
42 #define VQ_FEXP_BIAS 768 /* bias toward values smaller than 1. */
44 /* doesn't currently guard under/overflow */
45 long _float32_pack(float val){
53 exp= floor(log(val)/log(2.f)+.001); /* +epsilon */
54 mant=rint(ldexp(val,(VQ_FMAN-1)-exp));
55 exp=(exp+VQ_FEXP_BIAS)<<VQ_FMAN;
57 return(sign|exp|mant);
60 float _float32_unpack(long val){
61 double mant=val&0x1fffff;
62 int sign=val&0x80000000;
63 long exp =(val&0x7fe00000L)>>VQ_FMAN;
65 exp=exp-(VQ_FMAN-1)-VQ_FEXP_BIAS;
66 /* clamp excessive exponent values */
73 return(ldexp(mant,exp));
76 /* given a list of word lengths, generate a list of codewords. Works
77 for length ordered or unordered, always assigns the lowest valued
78 codewords first. Extended to handle unused entries (length 0) */
79 ogg_uint32_t *_make_words(char *l,long n,long sparsecount){
81 ogg_uint32_t marker[33];
82 ogg_uint32_t *r=_ogg_malloc((sparsecount?sparsecount:n)*sizeof(*r));
83 memset(marker,0,sizeof(marker));
88 ogg_uint32_t entry=marker[length];
90 /* when we claim a node for an entry, we also claim the nodes
91 below it (pruning off the imagined tree that may have dangled
92 from it) as well as blocking the use of any nodes directly
96 if(length<32 && (entry>>length)){
97 /* error condition; the lengths must specify an overpopulated tree */
103 /* Look to see if the next shorter marker points to the node
104 above. if so, update it and repeat. */
106 for(j=length;j>0;j--){
109 /* have to jump branches */
113 marker[j]=marker[j-1]<<1;
114 break; /* invariant says next upper marker would already
115 have been moved if it was on the same path */
121 /* prune the tree; the implicit invariant says all the longer
122 markers were dangling from our just-taken node. Dangle them
123 from our *new* node. */
124 for(j=length+1;j<33;j++)
125 if((marker[j]>>1) == entry){
127 marker[j]=marker[j-1]<<1;
131 if(sparsecount==0)count++;
134 /* any underpopulated tree must be rejected. */
135 /* Single-entry codebooks are a retconned extension to the spec.
136 They have a single codeword '0' of length 1 that results in an
137 underpopulated tree. Shield that case from the underformed tree check. */
138 if(!(count==1 && marker[2]==2)){
140 if(marker[i] & (0xffffffffUL>>(32-i))){
146 /* bitreverse the words because our bitwise packer/unpacker is LSb
148 for(i=0,count=0;i<n;i++){
152 temp|=(r[count]>>j)&1;
165 /* there might be a straightforward one-line way to do the below
166 that's portable and totally safe against roundoff, but I haven't
167 thought of it. Therefore, we opt on the side of caution */
168 long _book_maptype1_quantvals(const static_codebook *b){
173 vals=floor(pow((float)b->entries,1.f/b->dim));
175 /* the above *should* be reliable, but we'll not assume that FP is
176 ever reliable when bitstream sync is at stake; verify via integer
177 means that vals really is the greatest value of dim for which
178 vals^b->bim <= b->entries */
179 /* treat the above as an initial guess */
187 for(i=0;i<b->dim;i++){
188 if(b->entries/vals<acc)break;
190 if(LONG_MAX/(vals+1)<acc1)acc1=LONG_MAX;
193 if(i>=b->dim && acc<=b->entries && acc1>b->entries){
196 if(i<b->dim || acc>b->entries){
205 /* unpack the quantized list of values for encode/decode ***********/
206 /* we need to deal with two map types: in map type 1, the values are
207 generated algorithmically (each column of the vector counts through
208 the values in the quant vector). in map type 2, all the values came
209 in in an explicit list. Both value lists must be unpacked */
210 float *_book_unquantize(const static_codebook *b,int n,int *sparsemap){
212 if(b->maptype==1 || b->maptype==2){
214 float mindel=_float32_unpack(b->q_min);
215 float delta=_float32_unpack(b->q_delta);
216 float *r=_ogg_calloc(n*b->dim,sizeof(*r));
218 /* maptype 1 and 2 both use a quantized value vector, but
222 /* most of the time, entries%dimensions == 0, but we need to be
223 well defined. We define that the possible vales at each
224 scalar is values == entries/dim. If entries%dim != 0, we'll
225 have 'too few' values (values*dim<entries), which means that
226 we'll have 'left over' entries; left over entries use zeroed
227 values (and are wasted). So don't generate codebooks like
229 quantvals=_book_maptype1_quantvals(b);
230 for(j=0;j<b->entries;j++){
231 if((sparsemap && b->lengthlist[j]) || !sparsemap){
234 for(k=0;k<b->dim;k++){
235 int index= (j/indexdiv)%quantvals;
236 float val=b->quantlist[index];
237 val=fabs(val)*delta+mindel+last;
238 if(b->q_sequencep)last=val;
240 r[sparsemap[count]*b->dim+k]=val;
242 r[count*b->dim+k]=val;
251 for(j=0;j<b->entries;j++){
252 if((sparsemap && b->lengthlist[j]) || !sparsemap){
255 for(k=0;k<b->dim;k++){
256 float val=b->quantlist[j*b->dim+k];
257 val=fabs(val)*delta+mindel+last;
258 if(b->q_sequencep)last=val;
260 r[sparsemap[count]*b->dim+k]=val;
262 r[count*b->dim+k]=val;
275 void vorbis_staticbook_destroy(static_codebook *b){
277 if(b->quantlist)_ogg_free(b->quantlist);
278 if(b->lengthlist)_ogg_free(b->lengthlist);
279 memset(b,0,sizeof(*b));
281 } /* otherwise, it is in static memory */
284 void vorbis_book_clear(codebook *b){
285 /* static book is not cleared; we're likely called on the lookup and
286 the static codebook belongs to the info struct */
287 if(b->valuelist)_ogg_free(b->valuelist);
288 if(b->codelist)_ogg_free(b->codelist);
290 if(b->dec_index)_ogg_free(b->dec_index);
291 if(b->dec_codelengths)_ogg_free(b->dec_codelengths);
292 if(b->dec_firsttable)_ogg_free(b->dec_firsttable);
294 memset(b,0,sizeof(*b));
297 int vorbis_book_init_encode(codebook *c,const static_codebook *s){
299 memset(c,0,sizeof(*c));
301 c->entries=s->entries;
302 c->used_entries=s->entries;
304 c->codelist=_make_words(s->lengthlist,s->entries,0);
305 /* c->valuelist=_book_unquantize(s,s->entries,NULL); */
306 c->quantvals=_book_maptype1_quantvals(s);
307 c->minval=(int)rint(_float32_unpack(s->q_min));
308 c->delta=(int)rint(_float32_unpack(s->q_delta));
313 static ogg_uint32_t bitreverse(ogg_uint32_t x){
314 x= ((x>>16)&0x0000ffffUL) | ((x<<16)&0xffff0000UL);
315 x= ((x>> 8)&0x00ff00ffUL) | ((x<< 8)&0xff00ff00UL);
316 x= ((x>> 4)&0x0f0f0f0fUL) | ((x<< 4)&0xf0f0f0f0UL);
317 x= ((x>> 2)&0x33333333UL) | ((x<< 2)&0xccccccccUL);
318 return((x>> 1)&0x55555555UL) | ((x<< 1)&0xaaaaaaaaUL);
321 static int sort32a(const void *a,const void *b){
322 return ( **(ogg_uint32_t **)a>**(ogg_uint32_t **)b)-
323 ( **(ogg_uint32_t **)a<**(ogg_uint32_t **)b);
326 /* decode codebook arrangement is more heavily optimized than encode */
327 int vorbis_book_init_decode(codebook *c,const static_codebook *s){
331 memset(c,0,sizeof(*c));
333 /* count actually used entries and find max length */
334 for(i=0;i<s->entries;i++)
335 if(s->lengthlist[i]>0)
338 c->entries=s->entries;
343 /* two different remappings go on here.
345 First, we collapse the likely sparse codebook down only to
346 actually represented values/words. This collapsing needs to be
347 indexed as map-valueless books are used to encode original entry
348 positions as integers.
350 Second, we reorder all vectors, including the entry index above,
351 by sorted bitreversed codeword to allow treeless decode. */
354 ogg_uint32_t *codes=_make_words(s->lengthlist,s->entries,c->used_entries);
355 ogg_uint32_t **codep;
357 if(codes==NULL)goto err_out;
358 codep=malloc(sizeof(*codep)*n);
361 codes[i]=bitreverse(codes[i]);
365 qsort(codep,n,sizeof(*codep),sort32a);
367 sortindex=malloc(n*sizeof(*sortindex));
368 c->codelist=_ogg_malloc(n*sizeof(*c->codelist));
369 /* the index is a reverse index */
371 int position=codep[i]-codes;
372 sortindex[position]=i;
376 c->codelist[sortindex[i]]=codes[i];
379 c->valuelist=_book_unquantize(s,n,sortindex);
380 c->dec_index=_ogg_malloc(n*sizeof(*c->dec_index));
382 for(n=0,i=0;i<s->entries;i++)
383 if(s->lengthlist[i]>0)
384 c->dec_index[sortindex[n++]]=i;
386 c->dec_codelengths=_ogg_malloc(n*sizeof(*c->dec_codelengths));
388 for(n=0,i=0;i<s->entries;i++)
389 if(s->lengthlist[i]>0){
390 c->dec_codelengths[sortindex[n++]]=s->lengthlist[i];
391 if(s->lengthlist[i]>c->dec_maxlength)
392 c->dec_maxlength=s->lengthlist[i];
395 if(n==1 && c->dec_maxlength==1){
396 /* special case the 'single entry codebook' with a single bit
397 fastpath table (that always returns entry 0 )in order to use
398 unmodified decode paths. */
399 c->dec_firsttablen=1;
400 c->dec_firsttable=_ogg_calloc(2,sizeof(*c->dec_firsttable));
401 c->dec_firsttable[0]=c->dec_firsttable[1]=1;
404 c->dec_firsttablen=ov_ilog(c->used_entries)-4; /* this is magic */
405 if(c->dec_firsttablen<5)c->dec_firsttablen=5;
406 if(c->dec_firsttablen>8)c->dec_firsttablen=8;
408 tabn=1<<c->dec_firsttablen;
409 c->dec_firsttable=_ogg_calloc(tabn,sizeof(*c->dec_firsttable));
412 if(c->dec_codelengths[i]<=c->dec_firsttablen){
413 ogg_uint32_t orig=bitreverse(c->codelist[i]);
414 for(j=0;j<(1<<(c->dec_firsttablen-c->dec_codelengths[i]));j++)
415 c->dec_firsttable[orig|(j<<c->dec_codelengths[i])]=i+1;
419 /* now fill in 'unused' entries in the firsttable with hi/lo search
420 hints for the non-direct-hits */
422 ogg_uint32_t mask=0xfffffffeUL<<(31-c->dec_firsttablen);
426 ogg_uint32_t word=i<<(32-c->dec_firsttablen);
427 if(c->dec_firsttable[bitreverse(word)]==0){
428 while((lo+1)<n && c->codelist[lo+1]<=word)lo++;
429 while( hi<n && word>=(c->codelist[hi]&mask))hi++;
431 /* we only actually have 15 bits per hint to play with here.
432 In order to overflow gracefully (nothing breaks, efficiency
433 just drops), encode as the difference from the extremes. */
435 unsigned long loval=lo;
436 unsigned long hival=n-hi;
438 if(loval>0x7fff)loval=0x7fff;
439 if(hival>0x7fff)hival=0x7fff;
440 c->dec_firsttable[bitreverse(word)]=
441 0x80000000UL | (loval<<15) | hival;
453 vorbis_book_clear(c);
457 long vorbis_book_codeword(codebook *book,int entry){
458 if(book->c) /* only use with encode; decode optimizations are
459 allowed to break this */
460 return book->codelist[entry];
464 long vorbis_book_codelen(codebook *book,int entry){
465 if(book->c) /* only use with encode; decode optimizations are
466 allowed to break this */
467 return book->c->lengthlist[entry];
473 /* Unit tests of the dequantizer; this stuff will be OK
474 cross-platform, I simply want to be sure that special mapping cases
475 actually work properly; a bug could go unnoticed for a while */
482 full, explicit mapping
489 static long full_quantlist1[]={0,1,2,3, 4,5,6,7, 8,3,6,1};
490 static long partial_quantlist1[]={0,7,2};
493 static_codebook test1={
501 static float *test1_result=NULL;
503 /* linear, full mapping, nonsequential */
504 static_codebook test2={
508 -533200896,1611661312,4,0,
512 static float test2_result[]={-3,-2,-1,0, 1,2,3,4, 5,0,3,-2};
514 /* linear, full mapping, sequential */
515 static_codebook test3={
519 -533200896,1611661312,4,1,
523 static float test3_result[]={-3,-5,-6,-6, 1,3,6,10, 5,5,8,6};
525 /* linear, algorithmic mapping, nonsequential */
526 static_codebook test4={
530 -533200896,1611661312,4,0,
534 static float test4_result[]={-3,-3,-3, 4,-3,-3, -1,-3,-3,
535 -3, 4,-3, 4, 4,-3, -1, 4,-3,
536 -3,-1,-3, 4,-1,-3, -1,-1,-3,
537 -3,-3, 4, 4,-3, 4, -1,-3, 4,
538 -3, 4, 4, 4, 4, 4, -1, 4, 4,
539 -3,-1, 4, 4,-1, 4, -1,-1, 4,
540 -3,-3,-1, 4,-3,-1, -1,-3,-1,
541 -3, 4,-1, 4, 4,-1, -1, 4,-1,
542 -3,-1,-1, 4,-1,-1, -1,-1,-1};
544 /* linear, algorithmic mapping, sequential */
545 static_codebook test5={
549 -533200896,1611661312,4,1,
553 static float test5_result[]={-3,-6,-9, 4, 1,-2, -1,-4,-7,
554 -3, 1,-2, 4, 8, 5, -1, 3, 0,
555 -3,-4,-7, 4, 3, 0, -1,-2,-5,
556 -3,-6,-2, 4, 1, 5, -1,-4, 0,
557 -3, 1, 5, 4, 8,12, -1, 3, 7,
558 -3,-4, 0, 4, 3, 7, -1,-2, 2,
559 -3,-6,-7, 4, 1, 0, -1,-4,-5,
560 -3, 1, 0, 4, 8, 7, -1, 3, 2,
561 -3,-4,-5, 4, 3, 2, -1,-2,-3};
563 void run_test(static_codebook *b,float *comp){
564 float *out=_book_unquantize(b,b->entries,NULL);
569 fprintf(stderr,"_book_unquantize incorrectly returned NULL\n");
573 for(i=0;i<b->entries*b->dim;i++)
574 if(fabs(out[i]-comp[i])>.0001){
575 fprintf(stderr,"disagreement in unquantized and reference data:\n"
576 "position %d, %g != %g\n",i,out[i],comp[i]);
582 fprintf(stderr,"_book_unquantize returned a value array: \n"
583 " correct result should have been NULL\n");
591 /* run the nine dequant tests, and compare to the hand-rolled results */
592 fprintf(stderr,"Dequant test 1... ");
593 run_test(&test1,test1_result);
594 fprintf(stderr,"OK\nDequant test 2... ");
595 run_test(&test2,test2_result);
596 fprintf(stderr,"OK\nDequant test 3... ");
597 run_test(&test3,test3_result);
598 fprintf(stderr,"OK\nDequant test 4... ");
599 run_test(&test4,test4_result);
600 fprintf(stderr,"OK\nDequant test 5... ");
601 run_test(&test5,test5_result);
602 fprintf(stderr,"OK\n\n");