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source: downloads/libvorbis-1.2.0/lib/envelope.c @ 52

Last change on this file since 52 was 16, checked in by landauf, 17 years ago

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1/********************************************************************
2 *                                                                  *
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.       *
7 *                                                                  *
8 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2007             *
9 * by the Xiph.Org Foundation http://www.xiph.org/                  *
10 *                                                                  *
11 ********************************************************************
12
13 function: PCM data envelope analysis
14 last mod: $Id: envelope.c 13293 2007-07-24 00:09:47Z xiphmont $
15
16 ********************************************************************/
17
18#include <stdlib.h>
19#include <string.h>
20#include <stdio.h>
21#include <math.h>
22#include <ogg/ogg.h>
23#include "vorbis/codec.h"
24#include "codec_internal.h"
25
26#include "os.h"
27#include "scales.h"
28#include "envelope.h"
29#include "mdct.h"
30#include "misc.h"
31
32void _ve_envelope_init(envelope_lookup *e,vorbis_info *vi){
33  codec_setup_info *ci=vi->codec_setup;
34  vorbis_info_psy_global *gi=&ci->psy_g_param;
35  int ch=vi->channels;
36  int i,j;
37  int n=e->winlength=128;
38  e->searchstep=64; /* not random */
39
40  e->minenergy=gi->preecho_minenergy;
41  e->ch=ch;
42  e->storage=128;
43  e->cursor=ci->blocksizes[1]/2;
44  e->mdct_win=_ogg_calloc(n,sizeof(*e->mdct_win));
45  mdct_init(&e->mdct,n);
46
47  for(i=0;i<n;i++){
48    e->mdct_win[i]=sin(i/(n-1.)*M_PI);
49    e->mdct_win[i]*=e->mdct_win[i];
50  }
51
52  /* magic follows */
53  e->band[0].begin=2;  e->band[0].end=4;
54  e->band[1].begin=4;  e->band[1].end=5;
55  e->band[2].begin=6;  e->band[2].end=6;
56  e->band[3].begin=9;  e->band[3].end=8;
57  e->band[4].begin=13;  e->band[4].end=8;
58  e->band[5].begin=17;  e->band[5].end=8;
59  e->band[6].begin=22;  e->band[6].end=8;
60
61  for(j=0;j<VE_BANDS;j++){
62    n=e->band[j].end;
63    e->band[j].window=_ogg_malloc(n*sizeof(*e->band[0].window));
64    for(i=0;i<n;i++){
65      e->band[j].window[i]=sin((i+.5)/n*M_PI);
66      e->band[j].total+=e->band[j].window[i];
67    }
68    e->band[j].total=1./e->band[j].total;
69  }
70 
71  e->filter=_ogg_calloc(VE_BANDS*ch,sizeof(*e->filter));
72  e->mark=_ogg_calloc(e->storage,sizeof(*e->mark));
73
74}
75
76void _ve_envelope_clear(envelope_lookup *e){
77  int i;
78  mdct_clear(&e->mdct);
79  for(i=0;i<VE_BANDS;i++)
80    _ogg_free(e->band[i].window);
81  _ogg_free(e->mdct_win);
82  _ogg_free(e->filter);
83  _ogg_free(e->mark);
84  memset(e,0,sizeof(*e));
85}
86
87/* fairly straight threshhold-by-band based until we find something
88   that works better and isn't patented. */
89
90static int _ve_amp(envelope_lookup *ve,
91                   vorbis_info_psy_global *gi,
92                   float *data,
93                   envelope_band *bands,
94                   envelope_filter_state *filters,
95                   long pos){
96  long n=ve->winlength;
97  int ret=0;
98  long i,j;
99  float decay;
100
101  /* we want to have a 'minimum bar' for energy, else we're just
102     basing blocks on quantization noise that outweighs the signal
103     itself (for low power signals) */
104
105  float minV=ve->minenergy;
106  float *vec=alloca(n*sizeof(*vec));
107
108  /* stretch is used to gradually lengthen the number of windows
109     considered prevoius-to-potential-trigger */
110  int stretch=max(VE_MINSTRETCH,ve->stretch/2);
111  float penalty=gi->stretch_penalty-(ve->stretch/2-VE_MINSTRETCH);
112  if(penalty<0.f)penalty=0.f;
113  if(penalty>gi->stretch_penalty)penalty=gi->stretch_penalty;
114 
115  /*_analysis_output_always("lpcm",seq2,data,n,0,0,
116    totalshift+pos*ve->searchstep);*/
117 
118 /* window and transform */
119  for(i=0;i<n;i++)
120    vec[i]=data[i]*ve->mdct_win[i];
121  mdct_forward(&ve->mdct,vec,vec);
122 
123  /*_analysis_output_always("mdct",seq2,vec,n/2,0,1,0); */
124
125  /* near-DC spreading function; this has nothing to do with
126     psychoacoustics, just sidelobe leakage and window size */
127  {
128    float temp=vec[0]*vec[0]+.7*vec[1]*vec[1]+.2*vec[2]*vec[2];
129    int ptr=filters->nearptr;
130
131    /* the accumulation is regularly refreshed from scratch to avoid
132       floating point creep */
133    if(ptr==0){
134      decay=filters->nearDC_acc=filters->nearDC_partialacc+temp;
135      filters->nearDC_partialacc=temp;
136    }else{
137      decay=filters->nearDC_acc+=temp;
138      filters->nearDC_partialacc+=temp;
139    }
140    filters->nearDC_acc-=filters->nearDC[ptr];
141    filters->nearDC[ptr]=temp;
142
143    decay*=(1./(VE_NEARDC+1));
144    filters->nearptr++;
145    if(filters->nearptr>=VE_NEARDC)filters->nearptr=0;
146    decay=todB(&decay)*.5-15.f;
147  }
148 
149  /* perform spreading and limiting, also smooth the spectrum.  yes,
150     the MDCT results in all real coefficients, but it still *behaves*
151     like real/imaginary pairs */
152  for(i=0;i<n/2;i+=2){
153    float val=vec[i]*vec[i]+vec[i+1]*vec[i+1];
154    val=todB(&val)*.5f;
155    if(val<decay)val=decay;
156    if(val<minV)val=minV;
157    vec[i>>1]=val;
158    decay-=8.;
159  }
160
161  /*_analysis_output_always("spread",seq2++,vec,n/4,0,0,0);*/
162 
163  /* perform preecho/postecho triggering by band */
164  for(j=0;j<VE_BANDS;j++){
165    float acc=0.;
166    float valmax,valmin;
167
168    /* accumulate amplitude */
169    for(i=0;i<bands[j].end;i++)
170      acc+=vec[i+bands[j].begin]*bands[j].window[i];
171   
172    acc*=bands[j].total;
173
174    /* convert amplitude to delta */
175    {
176      int p,this=filters[j].ampptr;
177      float postmax,postmin,premax=-99999.f,premin=99999.f;
178     
179      p=this;
180      p--;
181      if(p<0)p+=VE_AMP;
182      postmax=max(acc,filters[j].ampbuf[p]);
183      postmin=min(acc,filters[j].ampbuf[p]);
184     
185      for(i=0;i<stretch;i++){
186        p--;
187        if(p<0)p+=VE_AMP;
188        premax=max(premax,filters[j].ampbuf[p]);
189        premin=min(premin,filters[j].ampbuf[p]);
190      }
191     
192      valmin=postmin-premin;
193      valmax=postmax-premax;
194
195      /*filters[j].markers[pos]=valmax;*/
196      filters[j].ampbuf[this]=acc;
197      filters[j].ampptr++;
198      if(filters[j].ampptr>=VE_AMP)filters[j].ampptr=0;
199    }
200
201    /* look at min/max, decide trigger */
202    if(valmax>gi->preecho_thresh[j]+penalty){
203      ret|=1;
204      ret|=4;
205    }
206    if(valmin<gi->postecho_thresh[j]-penalty)ret|=2;
207  }
208 
209  return(ret);
210}
211
212#if 0
213static int seq=0;
214static ogg_int64_t totalshift=-1024;
215#endif
216
217long _ve_envelope_search(vorbis_dsp_state *v){
218  vorbis_info *vi=v->vi;
219  codec_setup_info *ci=vi->codec_setup;
220  vorbis_info_psy_global *gi=&ci->psy_g_param;
221  envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
222  long i,j;
223
224  int first=ve->current/ve->searchstep;
225  int last=v->pcm_current/ve->searchstep-VE_WIN;
226  if(first<0)first=0;
227
228  /* make sure we have enough storage to match the PCM */
229  if(last+VE_WIN+VE_POST>ve->storage){
230    ve->storage=last+VE_WIN+VE_POST; /* be sure */
231    ve->mark=_ogg_realloc(ve->mark,ve->storage*sizeof(*ve->mark));
232  }
233
234  for(j=first;j<last;j++){
235    int ret=0;
236
237    ve->stretch++;
238    if(ve->stretch>VE_MAXSTRETCH*2)
239      ve->stretch=VE_MAXSTRETCH*2;
240   
241    for(i=0;i<ve->ch;i++){
242      float *pcm=v->pcm[i]+ve->searchstep*(j);
243      ret|=_ve_amp(ve,gi,pcm,ve->band,ve->filter+i*VE_BANDS,j);
244    }
245
246    ve->mark[j+VE_POST]=0;
247    if(ret&1){
248      ve->mark[j]=1;
249      ve->mark[j+1]=1;
250    }
251
252    if(ret&2){
253      ve->mark[j]=1;
254      if(j>0)ve->mark[j-1]=1;
255    }
256
257    if(ret&4)ve->stretch=-1;
258  }
259
260  ve->current=last*ve->searchstep;
261
262  {
263    long centerW=v->centerW;
264    long testW=
265      centerW+
266      ci->blocksizes[v->W]/4+
267      ci->blocksizes[1]/2+
268      ci->blocksizes[0]/4;
269   
270    j=ve->cursor;
271   
272    while(j<ve->current-(ve->searchstep)){/* account for postecho
273                                             working back one window */
274      if(j>=testW)return(1);
275 
276      ve->cursor=j;
277
278      if(ve->mark[j/ve->searchstep]){
279        if(j>centerW){
280
281#if 0
282          if(j>ve->curmark){
283            float *marker=alloca(v->pcm_current*sizeof(*marker));
284            int l,m;
285            memset(marker,0,sizeof(*marker)*v->pcm_current);
286            fprintf(stderr,"mark! seq=%d, cursor:%fs time:%fs\n",
287                    seq,
288                    (totalshift+ve->cursor)/44100.,
289                    (totalshift+j)/44100.);
290            _analysis_output_always("pcmL",seq,v->pcm[0],v->pcm_current,0,0,totalshift);
291            _analysis_output_always("pcmR",seq,v->pcm[1],v->pcm_current,0,0,totalshift);
292
293            _analysis_output_always("markL",seq,v->pcm[0],j,0,0,totalshift);
294            _analysis_output_always("markR",seq,v->pcm[1],j,0,0,totalshift);
295           
296            for(m=0;m<VE_BANDS;m++){
297              char buf[80];
298              sprintf(buf,"delL%d",m);
299              for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m].markers[l]*.1;
300              _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
301            }
302
303            for(m=0;m<VE_BANDS;m++){
304              char buf[80];
305              sprintf(buf,"delR%d",m);
306              for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m+VE_BANDS].markers[l]*.1;
307              _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
308            }
309
310            for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->mark[l]*.4;
311            _analysis_output_always("mark",seq,marker,v->pcm_current,0,0,totalshift);
312           
313           
314            seq++;
315           
316          }
317#endif
318
319          ve->curmark=j;
320          if(j>=testW)return(1);
321          return(0);
322        }
323      }
324      j+=ve->searchstep;
325    }
326  }
327 
328  return(-1);
329}
330
331int _ve_envelope_mark(vorbis_dsp_state *v){
332  envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
333  vorbis_info *vi=v->vi;
334  codec_setup_info *ci=vi->codec_setup;
335  long centerW=v->centerW;
336  long beginW=centerW-ci->blocksizes[v->W]/4;
337  long endW=centerW+ci->blocksizes[v->W]/4;
338  if(v->W){
339    beginW-=ci->blocksizes[v->lW]/4;
340    endW+=ci->blocksizes[v->nW]/4;
341  }else{
342    beginW-=ci->blocksizes[0]/4;
343    endW+=ci->blocksizes[0]/4;
344  }
345
346  if(ve->curmark>=beginW && ve->curmark<endW)return(1);
347  {
348    long first=beginW/ve->searchstep;
349    long last=endW/ve->searchstep;
350    long i;
351    for(i=first;i<last;i++)
352      if(ve->mark[i])return(1);
353  }
354  return(0);
355}
356
357void _ve_envelope_shift(envelope_lookup *e,long shift){
358  int smallsize=e->current/e->searchstep+VE_POST; /* adjust for placing marks
359                                                     ahead of ve->current */
360  int smallshift=shift/e->searchstep;
361
362  memmove(e->mark,e->mark+smallshift,(smallsize-smallshift)*sizeof(*e->mark));
363 
364#if 0
365  for(i=0;i<VE_BANDS*e->ch;i++)
366    memmove(e->filter[i].markers,
367            e->filter[i].markers+smallshift,
368            (1024-smallshift)*sizeof(*(*e->filter).markers));
369  totalshift+=shift;
370#endif
371
372  e->current-=shift;
373  if(e->curmark>=0)
374    e->curmark-=shift;
375  e->cursor-=shift;
376}
377
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