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 1994-2009 *
9 * by the Xiph.Org Foundation http://www.xiph.org/ *
11 ********************************************************************
13 function: basic shared codebook operations
16 ********************************************************************/
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 return(ldexp(mant,exp-(VQ_FMAN-1)-VQ_FEXP_BIAS));
68 /* given a list of word lengths, generate a list of codewords. Works
69 for length ordered or unordered, always assigns the lowest valued
70 codewords first. Extended to handle unused entries (length 0) */
71 ogg_uint32_t *_make_words(char *l,long n,long sparsecount){
73 ogg_uint32_t marker[33];
74 ogg_uint32_t *r=_ogg_malloc((sparsecount?sparsecount:n)*sizeof(*r));
75 memset(marker,0,sizeof(marker));
80 ogg_uint32_t entry=marker[length];
82 /* when we claim a node for an entry, we also claim the nodes
83 below it (pruning off the imagined tree that may have dangled
84 from it) as well as blocking the use of any nodes directly
88 if(length<32 && (entry>>length)){
89 /* error condition; the lengths must specify an overpopulated tree */
95 /* Look to see if the next shorter marker points to the node
96 above. if so, update it and repeat. */
98 for(j=length;j>0;j--){
101 /* have to jump branches */
105 marker[j]=marker[j-1]<<1;
106 break; /* invariant says next upper marker would already
107 have been moved if it was on the same path */
113 /* prune the tree; the implicit invariant says all the longer
114 markers were dangling from our just-taken node. Dangle them
115 from our *new* node. */
116 for(j=length+1;j<33;j++)
117 if((marker[j]>>1) == entry){
119 marker[j]=marker[j-1]<<1;
123 if(sparsecount==0)count++;
126 /* any underpopulated tree must be rejected. */
127 /* Single-entry codebooks are a retconned extension to the spec.
128 They have a single codeword '0' of length 1 that results in an
129 underpopulated tree. Shield that case from the underformed tree check. */
130 if(!(count==1 && marker[2]==2)){
132 if(marker[i] & (0xffffffffUL>>(32-i))){
138 /* bitreverse the words because our bitwise packer/unpacker is LSb
140 for(i=0,count=0;i<n;i++){
144 temp|=(r[count]>>j)&1;
157 /* there might be a straightforward one-line way to do the below
158 that's portable and totally safe against roundoff, but I haven't
159 thought of it. Therefore, we opt on the side of caution */
160 long _book_maptype1_quantvals(const static_codebook *b){
161 long vals=floor(pow((float)b->entries,1.f/b->dim));
163 /* the above *should* be reliable, but we'll not assume that FP is
164 ever reliable when bitstream sync is at stake; verify via integer
165 means that vals really is the greatest value of dim for which
166 vals^b->bim <= b->entries */
167 /* treat the above as an initial guess */
172 for(i=0;i<b->dim;i++){
176 if(acc<=b->entries && acc1>b->entries){
188 /* unpack the quantized list of values for encode/decode ***********/
189 /* we need to deal with two map types: in map type 1, the values are
190 generated algorithmically (each column of the vector counts through
191 the values in the quant vector). in map type 2, all the values came
192 in in an explicit list. Both value lists must be unpacked */
193 float *_book_unquantize(const static_codebook *b,int n,int *sparsemap){
195 if(b->maptype==1 || b->maptype==2){
197 float mindel=_float32_unpack(b->q_min);
198 float delta=_float32_unpack(b->q_delta);
199 float *r=_ogg_calloc(n*b->dim,sizeof(*r));
201 /* maptype 1 and 2 both use a quantized value vector, but
205 /* most of the time, entries%dimensions == 0, but we need to be
206 well defined. We define that the possible vales at each
207 scalar is values == entries/dim. If entries%dim != 0, we'll
208 have 'too few' values (values*dim<entries), which means that
209 we'll have 'left over' entries; left over entries use zeroed
210 values (and are wasted). So don't generate codebooks like
212 quantvals=_book_maptype1_quantvals(b);
213 for(j=0;j<b->entries;j++){
214 if((sparsemap && b->lengthlist[j]) || !sparsemap){
217 for(k=0;k<b->dim;k++){
218 int index= (j/indexdiv)%quantvals;
219 float val=b->quantlist[index];
220 val=fabs(val)*delta+mindel+last;
221 if(b->q_sequencep)last=val;
223 r[sparsemap[count]*b->dim+k]=val;
225 r[count*b->dim+k]=val;
234 for(j=0;j<b->entries;j++){
235 if((sparsemap && b->lengthlist[j]) || !sparsemap){
238 for(k=0;k<b->dim;k++){
239 float val=b->quantlist[j*b->dim+k];
240 val=fabs(val)*delta+mindel+last;
241 if(b->q_sequencep)last=val;
243 r[sparsemap[count]*b->dim+k]=val;
245 r[count*b->dim+k]=val;
258 void vorbis_staticbook_destroy(static_codebook *b){
260 if(b->quantlist)_ogg_free(b->quantlist);
261 if(b->lengthlist)_ogg_free(b->lengthlist);
262 memset(b,0,sizeof(*b));
264 } /* otherwise, it is in static memory */
267 void vorbis_book_clear(codebook *b){
268 /* static book is not cleared; we're likely called on the lookup and
269 the static codebook belongs to the info struct */
270 if(b->valuelist)_ogg_free(b->valuelist);
271 if(b->codelist)_ogg_free(b->codelist);
273 if(b->dec_index)_ogg_free(b->dec_index);
274 if(b->dec_codelengths)_ogg_free(b->dec_codelengths);
275 if(b->dec_firsttable)_ogg_free(b->dec_firsttable);
277 memset(b,0,sizeof(*b));
280 int vorbis_book_init_encode(codebook *c,const static_codebook *s){
282 memset(c,0,sizeof(*c));
284 c->entries=s->entries;
285 c->used_entries=s->entries;
287 c->codelist=_make_words(s->lengthlist,s->entries,0);
288 //c->valuelist=_book_unquantize(s,s->entries,NULL);
289 c->quantvals=_book_maptype1_quantvals(s);
290 c->minval=(int)rint(_float32_unpack(s->q_min));
291 c->delta=(int)rint(_float32_unpack(s->q_delta));
296 static ogg_uint32_t bitreverse(ogg_uint32_t x){
297 x= ((x>>16)&0x0000ffffUL) | ((x<<16)&0xffff0000UL);
298 x= ((x>> 8)&0x00ff00ffUL) | ((x<< 8)&0xff00ff00UL);
299 x= ((x>> 4)&0x0f0f0f0fUL) | ((x<< 4)&0xf0f0f0f0UL);
300 x= ((x>> 2)&0x33333333UL) | ((x<< 2)&0xccccccccUL);
301 return((x>> 1)&0x55555555UL) | ((x<< 1)&0xaaaaaaaaUL);
304 static int sort32a(const void *a,const void *b){
305 return ( **(ogg_uint32_t **)a>**(ogg_uint32_t **)b)-
306 ( **(ogg_uint32_t **)a<**(ogg_uint32_t **)b);
309 /* decode codebook arrangement is more heavily optimized than encode */
310 int vorbis_book_init_decode(codebook *c,const static_codebook *s){
314 memset(c,0,sizeof(*c));
316 /* count actually used entries and find max length */
317 for(i=0;i<s->entries;i++)
318 if(s->lengthlist[i]>0)
321 c->entries=s->entries;
326 /* two different remappings go on here.
328 First, we collapse the likely sparse codebook down only to
329 actually represented values/words. This collapsing needs to be
330 indexed as map-valueless books are used to encode original entry
331 positions as integers.
333 Second, we reorder all vectors, including the entry index above,
334 by sorted bitreversed codeword to allow treeless decode. */
337 ogg_uint32_t *codes=_make_words(s->lengthlist,s->entries,c->used_entries);
338 ogg_uint32_t **codep=alloca(sizeof(*codep)*n);
340 if(codes==NULL)goto err_out;
343 codes[i]=bitreverse(codes[i]);
347 qsort(codep,n,sizeof(*codep),sort32a);
349 sortindex=alloca(n*sizeof(*sortindex));
350 c->codelist=_ogg_malloc(n*sizeof(*c->codelist));
351 /* the index is a reverse index */
353 int position=codep[i]-codes;
354 sortindex[position]=i;
358 c->codelist[sortindex[i]]=codes[i];
361 c->valuelist=_book_unquantize(s,n,sortindex);
362 c->dec_index=_ogg_malloc(n*sizeof(*c->dec_index));
364 for(n=0,i=0;i<s->entries;i++)
365 if(s->lengthlist[i]>0)
366 c->dec_index[sortindex[n++]]=i;
368 c->dec_codelengths=_ogg_malloc(n*sizeof(*c->dec_codelengths));
370 for(n=0,i=0;i<s->entries;i++)
371 if(s->lengthlist[i]>0){
372 c->dec_codelengths[sortindex[n++]]=s->lengthlist[i];
373 if(s->lengthlist[i]>c->dec_maxlength)
374 c->dec_maxlength=s->lengthlist[i];
377 if(n==1 && c->dec_maxlength==1){
378 /* special case the 'single entry codebook' with a single bit
379 fastpath table (that always returns entry 0 )in order to use
380 unmodified decode paths. */
381 c->dec_firsttablen=1;
382 c->dec_firsttable=_ogg_calloc(2,sizeof(*c->dec_firsttable));
383 c->dec_firsttable[0]=c->dec_firsttable[1]=1;
386 c->dec_firsttablen=ov_ilog(c->used_entries)-4; /* this is magic */
387 if(c->dec_firsttablen<5)c->dec_firsttablen=5;
388 if(c->dec_firsttablen>8)c->dec_firsttablen=8;
390 tabn=1<<c->dec_firsttablen;
391 c->dec_firsttable=_ogg_calloc(tabn,sizeof(*c->dec_firsttable));
394 if(c->dec_codelengths[i]<=c->dec_firsttablen){
395 ogg_uint32_t orig=bitreverse(c->codelist[i]);
396 for(j=0;j<(1<<(c->dec_firsttablen-c->dec_codelengths[i]));j++)
397 c->dec_firsttable[orig|(j<<c->dec_codelengths[i])]=i+1;
401 /* now fill in 'unused' entries in the firsttable with hi/lo search
402 hints for the non-direct-hits */
404 ogg_uint32_t mask=0xfffffffeUL<<(31-c->dec_firsttablen);
408 ogg_uint32_t word=i<<(32-c->dec_firsttablen);
409 if(c->dec_firsttable[bitreverse(word)]==0){
410 while((lo+1)<n && c->codelist[lo+1]<=word)lo++;
411 while( hi<n && word>=(c->codelist[hi]&mask))hi++;
413 /* we only actually have 15 bits per hint to play with here.
414 In order to overflow gracefully (nothing breaks, efficiency
415 just drops), encode as the difference from the extremes. */
417 unsigned long loval=lo;
418 unsigned long hival=n-hi;
420 if(loval>0x7fff)loval=0x7fff;
421 if(hival>0x7fff)hival=0x7fff;
422 c->dec_firsttable[bitreverse(word)]=
423 0x80000000UL | (loval<<15) | hival;
433 vorbis_book_clear(c);
437 long vorbis_book_codeword(codebook *book,int entry){
438 if(book->c) /* only use with encode; decode optimizations are
439 allowed to break this */
440 return book->codelist[entry];
444 long vorbis_book_codelen(codebook *book,int entry){
445 if(book->c) /* only use with encode; decode optimizations are
446 allowed to break this */
447 return book->c->lengthlist[entry];
453 /* Unit tests of the dequantizer; this stuff will be OK
454 cross-platform, I simply want to be sure that special mapping cases
455 actually work properly; a bug could go unnoticed for a while */
462 full, explicit mapping
469 static long full_quantlist1[]={0,1,2,3, 4,5,6,7, 8,3,6,1};
470 static long partial_quantlist1[]={0,7,2};
473 static_codebook test1={
481 static float *test1_result=NULL;
483 /* linear, full mapping, nonsequential */
484 static_codebook test2={
488 -533200896,1611661312,4,0,
492 static float test2_result[]={-3,-2,-1,0, 1,2,3,4, 5,0,3,-2};
494 /* linear, full mapping, sequential */
495 static_codebook test3={
499 -533200896,1611661312,4,1,
503 static float test3_result[]={-3,-5,-6,-6, 1,3,6,10, 5,5,8,6};
505 /* linear, algorithmic mapping, nonsequential */
506 static_codebook test4={
510 -533200896,1611661312,4,0,
514 static float test4_result[]={-3,-3,-3, 4,-3,-3, -1,-3,-3,
515 -3, 4,-3, 4, 4,-3, -1, 4,-3,
516 -3,-1,-3, 4,-1,-3, -1,-1,-3,
517 -3,-3, 4, 4,-3, 4, -1,-3, 4,
518 -3, 4, 4, 4, 4, 4, -1, 4, 4,
519 -3,-1, 4, 4,-1, 4, -1,-1, 4,
520 -3,-3,-1, 4,-3,-1, -1,-3,-1,
521 -3, 4,-1, 4, 4,-1, -1, 4,-1,
522 -3,-1,-1, 4,-1,-1, -1,-1,-1};
524 /* linear, algorithmic mapping, sequential */
525 static_codebook test5={
529 -533200896,1611661312,4,1,
533 static float test5_result[]={-3,-6,-9, 4, 1,-2, -1,-4,-7,
534 -3, 1,-2, 4, 8, 5, -1, 3, 0,
535 -3,-4,-7, 4, 3, 0, -1,-2,-5,
536 -3,-6,-2, 4, 1, 5, -1,-4, 0,
537 -3, 1, 5, 4, 8,12, -1, 3, 7,
538 -3,-4, 0, 4, 3, 7, -1,-2, 2,
539 -3,-6,-7, 4, 1, 0, -1,-4,-5,
540 -3, 1, 0, 4, 8, 7, -1, 3, 2,
541 -3,-4,-5, 4, 3, 2, -1,-2,-3};
543 void run_test(static_codebook *b,float *comp){
544 float *out=_book_unquantize(b,b->entries,NULL);
549 fprintf(stderr,"_book_unquantize incorrectly returned NULL\n");
553 for(i=0;i<b->entries*b->dim;i++)
554 if(fabs(out[i]-comp[i])>.0001){
555 fprintf(stderr,"disagreement in unquantized and reference data:\n"
556 "position %d, %g != %g\n",i,out[i],comp[i]);
562 fprintf(stderr,"_book_unquantize returned a value array: \n"
563 " correct result should have been NULL\n");
570 /* run the nine dequant tests, and compare to the hand-rolled results */
571 fprintf(stderr,"Dequant test 1... ");
572 run_test(&test1,test1_result);
573 fprintf(stderr,"OK\nDequant test 2... ");
574 run_test(&test2,test2_result);
575 fprintf(stderr,"OK\nDequant test 3... ");
576 run_test(&test3,test3_result);
577 fprintf(stderr,"OK\nDequant test 4... ");
578 run_test(&test4,test4_result);
579 fprintf(stderr,"OK\nDequant test 5... ");
580 run_test(&test5,test5_result);
581 fprintf(stderr,"OK\n\n");