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 /* sanity check the huffman tree; an underpopulated tree must be
127 rejected. The only exception is the one-node pseudo-nil tree,
128 which appears to be underpopulated because the tree doesn't
129 really exist; there's only one possible 'codeword' or zero bits,
130 but the above tree-gen code doesn't mark that. */
131 if(sparsecount != 1){
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){
162 long vals=floor(pow((float)b->entries,1.f/b->dim));
164 /* the above *should* be reliable, but we'll not assume that FP is
165 ever reliable when bitstream sync is at stake; verify via integer
166 means that vals really is the greatest value of dim for which
167 vals^b->bim <= b->entries */
168 /* treat the above as an initial guess */
173 for(i=0;i<b->dim;i++){
177 if(acc<=b->entries && acc1>b->entries){
189 /* unpack the quantized list of values for encode/decode ***********/
190 /* we need to deal with two map types: in map type 1, the values are
191 generated algorithmically (each column of the vector counts through
192 the values in the quant vector). in map type 2, all the values came
193 in in an explicit list. Both value lists must be unpacked */
194 float *_book_unquantize(const static_codebook *b,int n,int *sparsemap){
196 if(b->maptype==1 || b->maptype==2){
198 float mindel=_float32_unpack(b->q_min);
199 float delta=_float32_unpack(b->q_delta);
200 float *r=_ogg_calloc(n*b->dim,sizeof(*r));
202 /* maptype 1 and 2 both use a quantized value vector, but
206 /* most of the time, entries%dimensions == 0, but we need to be
207 well defined. We define that the possible vales at each
208 scalar is values == entries/dim. If entries%dim != 0, we'll
209 have 'too few' values (values*dim<entries), which means that
210 we'll have 'left over' entries; left over entries use zeroed
211 values (and are wasted). So don't generate codebooks like
213 quantvals=_book_maptype1_quantvals(b);
214 for(j=0;j<b->entries;j++){
215 if((sparsemap && b->lengthlist[j]) || !sparsemap){
218 for(k=0;k<b->dim;k++){
219 int index= (j/indexdiv)%quantvals;
220 float val=b->quantlist[index];
221 val=fabs(val)*delta+mindel+last;
222 if(b->q_sequencep)last=val;
224 r[sparsemap[count]*b->dim+k]=val;
226 r[count*b->dim+k]=val;
235 for(j=0;j<b->entries;j++){
236 if((sparsemap && b->lengthlist[j]) || !sparsemap){
239 for(k=0;k<b->dim;k++){
240 float val=b->quantlist[j*b->dim+k];
241 val=fabs(val)*delta+mindel+last;
242 if(b->q_sequencep)last=val;
244 r[sparsemap[count]*b->dim+k]=val;
246 r[count*b->dim+k]=val;
259 void vorbis_staticbook_destroy(static_codebook *b){
261 if(b->quantlist)_ogg_free(b->quantlist);
262 if(b->lengthlist)_ogg_free(b->lengthlist);
263 memset(b,0,sizeof(*b));
265 } /* otherwise, it is in static memory */
268 void vorbis_book_clear(codebook *b){
269 /* static book is not cleared; we're likely called on the lookup and
270 the static codebook belongs to the info struct */
271 if(b->valuelist)_ogg_free(b->valuelist);
272 if(b->codelist)_ogg_free(b->codelist);
274 if(b->dec_index)_ogg_free(b->dec_index);
275 if(b->dec_codelengths)_ogg_free(b->dec_codelengths);
276 if(b->dec_firsttable)_ogg_free(b->dec_firsttable);
278 memset(b,0,sizeof(*b));
281 int vorbis_book_init_encode(codebook *c,const static_codebook *s){
283 memset(c,0,sizeof(*c));
285 c->entries=s->entries;
286 c->used_entries=s->entries;
288 c->codelist=_make_words(s->lengthlist,s->entries,0);
289 //c->valuelist=_book_unquantize(s,s->entries,NULL);
290 c->quantvals=_book_maptype1_quantvals(s);
291 c->minval=(int)rint(_float32_unpack(s->q_min));
292 c->delta=(int)rint(_float32_unpack(s->q_delta));
297 static ogg_uint32_t bitreverse(ogg_uint32_t x){
298 x= ((x>>16)&0x0000ffffUL) | ((x<<16)&0xffff0000UL);
299 x= ((x>> 8)&0x00ff00ffUL) | ((x<< 8)&0xff00ff00UL);
300 x= ((x>> 4)&0x0f0f0f0fUL) | ((x<< 4)&0xf0f0f0f0UL);
301 x= ((x>> 2)&0x33333333UL) | ((x<< 2)&0xccccccccUL);
302 return((x>> 1)&0x55555555UL) | ((x<< 1)&0xaaaaaaaaUL);
305 static int sort32a(const void *a,const void *b){
306 return ( **(ogg_uint32_t **)a>**(ogg_uint32_t **)b)-
307 ( **(ogg_uint32_t **)a<**(ogg_uint32_t **)b);
310 /* decode codebook arrangement is more heavily optimized than encode */
311 int vorbis_book_init_decode(codebook *c,const static_codebook *s){
314 memset(c,0,sizeof(*c));
316 /* count actually used entries */
317 for(i=0;i<s->entries;i++)
318 if(s->lengthlist[i]>0)
321 c->entries=s->entries;
327 /* two different remappings go on here.
329 First, we collapse the likely sparse codebook down only to
330 actually represented values/words. This collapsing needs to be
331 indexed as map-valueless books are used to encode original entry
332 positions as integers.
334 Second, we reorder all vectors, including the entry index above,
335 by sorted bitreversed codeword to allow treeless decode. */
338 ogg_uint32_t *codes=_make_words(s->lengthlist,s->entries,c->used_entries);
339 ogg_uint32_t **codep=alloca(sizeof(*codep)*n);
341 if(codes==NULL)goto err_out;
344 codes[i]=bitreverse(codes[i]);
348 qsort(codep,n,sizeof(*codep),sort32a);
350 sortindex=alloca(n*sizeof(*sortindex));
351 c->codelist=_ogg_malloc(n*sizeof(*c->codelist));
352 /* the index is a reverse index */
354 int position=codep[i]-codes;
355 sortindex[position]=i;
359 c->codelist[sortindex[i]]=codes[i];
363 c->valuelist=_book_unquantize(s,n,sortindex);
364 c->dec_index=_ogg_malloc(n*sizeof(*c->dec_index));
366 for(n=0,i=0;i<s->entries;i++)
367 if(s->lengthlist[i]>0)
368 c->dec_index[sortindex[n++]]=i;
370 c->dec_codelengths=_ogg_malloc(n*sizeof(*c->dec_codelengths));
371 for(n=0,i=0;i<s->entries;i++)
372 if(s->lengthlist[i]>0)
373 c->dec_codelengths[sortindex[n++]]=s->lengthlist[i];
375 c->dec_firsttablen=ov_ilog(c->used_entries)-4; /* this is magic */
376 if(c->dec_firsttablen<5)c->dec_firsttablen=5;
377 if(c->dec_firsttablen>8)c->dec_firsttablen=8;
379 tabn=1<<c->dec_firsttablen;
380 c->dec_firsttable=_ogg_calloc(tabn,sizeof(*c->dec_firsttable));
384 if(c->dec_maxlength<c->dec_codelengths[i])
385 c->dec_maxlength=c->dec_codelengths[i];
386 if(c->dec_codelengths[i]<=c->dec_firsttablen){
387 ogg_uint32_t orig=bitreverse(c->codelist[i]);
388 for(j=0;j<(1<<(c->dec_firsttablen-c->dec_codelengths[i]));j++)
389 c->dec_firsttable[orig|(j<<c->dec_codelengths[i])]=i+1;
393 /* now fill in 'unused' entries in the firsttable with hi/lo search
394 hints for the non-direct-hits */
396 ogg_uint32_t mask=0xfffffffeUL<<(31-c->dec_firsttablen);
400 ogg_uint32_t word=i<<(32-c->dec_firsttablen);
401 if(c->dec_firsttable[bitreverse(word)]==0){
402 while((lo+1)<n && c->codelist[lo+1]<=word)lo++;
403 while( hi<n && word>=(c->codelist[hi]&mask))hi++;
405 /* we only actually have 15 bits per hint to play with here.
406 In order to overflow gracefully (nothing breaks, efficiency
407 just drops), encode as the difference from the extremes. */
409 unsigned long loval=lo;
410 unsigned long hival=n-hi;
412 if(loval>0x7fff)loval=0x7fff;
413 if(hival>0x7fff)hival=0x7fff;
414 c->dec_firsttable[bitreverse(word)]=
415 0x80000000UL | (loval<<15) | hival;
424 vorbis_book_clear(c);
428 long vorbis_book_codeword(codebook *book,int entry){
429 if(book->c) /* only use with encode; decode optimizations are
430 allowed to break this */
431 return book->codelist[entry];
435 long vorbis_book_codelen(codebook *book,int entry){
436 if(book->c) /* only use with encode; decode optimizations are
437 allowed to break this */
438 return book->c->lengthlist[entry];
444 /* Unit tests of the dequantizer; this stuff will be OK
445 cross-platform, I simply want to be sure that special mapping cases
446 actually work properly; a bug could go unnoticed for a while */
453 full, explicit mapping
460 static long full_quantlist1[]={0,1,2,3, 4,5,6,7, 8,3,6,1};
461 static long partial_quantlist1[]={0,7,2};
464 static_codebook test1={
472 static float *test1_result=NULL;
474 /* linear, full mapping, nonsequential */
475 static_codebook test2={
479 -533200896,1611661312,4,0,
483 static float test2_result[]={-3,-2,-1,0, 1,2,3,4, 5,0,3,-2};
485 /* linear, full mapping, sequential */
486 static_codebook test3={
490 -533200896,1611661312,4,1,
494 static float test3_result[]={-3,-5,-6,-6, 1,3,6,10, 5,5,8,6};
496 /* linear, algorithmic mapping, nonsequential */
497 static_codebook test4={
501 -533200896,1611661312,4,0,
505 static float test4_result[]={-3,-3,-3, 4,-3,-3, -1,-3,-3,
506 -3, 4,-3, 4, 4,-3, -1, 4,-3,
507 -3,-1,-3, 4,-1,-3, -1,-1,-3,
508 -3,-3, 4, 4,-3, 4, -1,-3, 4,
509 -3, 4, 4, 4, 4, 4, -1, 4, 4,
510 -3,-1, 4, 4,-1, 4, -1,-1, 4,
511 -3,-3,-1, 4,-3,-1, -1,-3,-1,
512 -3, 4,-1, 4, 4,-1, -1, 4,-1,
513 -3,-1,-1, 4,-1,-1, -1,-1,-1};
515 /* linear, algorithmic mapping, sequential */
516 static_codebook test5={
520 -533200896,1611661312,4,1,
524 static float test5_result[]={-3,-6,-9, 4, 1,-2, -1,-4,-7,
525 -3, 1,-2, 4, 8, 5, -1, 3, 0,
526 -3,-4,-7, 4, 3, 0, -1,-2,-5,
527 -3,-6,-2, 4, 1, 5, -1,-4, 0,
528 -3, 1, 5, 4, 8,12, -1, 3, 7,
529 -3,-4, 0, 4, 3, 7, -1,-2, 2,
530 -3,-6,-7, 4, 1, 0, -1,-4,-5,
531 -3, 1, 0, 4, 8, 7, -1, 3, 2,
532 -3,-4,-5, 4, 3, 2, -1,-2,-3};
534 void run_test(static_codebook *b,float *comp){
535 float *out=_book_unquantize(b,b->entries,NULL);
540 fprintf(stderr,"_book_unquantize incorrectly returned NULL\n");
544 for(i=0;i<b->entries*b->dim;i++)
545 if(fabs(out[i]-comp[i])>.0001){
546 fprintf(stderr,"disagreement in unquantized and reference data:\n"
547 "position %d, %g != %g\n",i,out[i],comp[i]);
553 fprintf(stderr,"_book_unquantize returned a value array: \n"
554 " correct result should have been NULL\n");
561 /* run the nine dequant tests, and compare to the hand-rolled results */
562 fprintf(stderr,"Dequant test 1... ");
563 run_test(&test1,test1_result);
564 fprintf(stderr,"OK\nDequant test 2... ");
565 run_test(&test2,test2_result);
566 fprintf(stderr,"OK\nDequant test 3... ");
567 run_test(&test3,test3_result);
568 fprintf(stderr,"OK\nDequant test 4... ");
569 run_test(&test4,test4_result);
570 fprintf(stderr,"OK\nDequant test 5... ");
571 run_test(&test5,test5_result);
572 fprintf(stderr,"OK\n\n");