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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 1994-2002             *
9  * by the XIPHOPHORUS Company http://www.xiph.org/                  *
10  *                                                                  *
11  ********************************************************************
12
13  function: PCM data envelope analysis 
14  last mod: $Id: envelope.c,v 1.54 2003/09/05 23:17:49 giles Exp $
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
32 void _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
76 void _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
90 static 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
213 static int seq=0;
214 static ogg_int64_t totalshift=-1024;
215 #endif
216
217 long _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
331 int _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
357 void _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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