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8  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009             *
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 16227 2009-07-08 06:58:46Z 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 
_ve_envelope_init(envelope_lookup * e,vorbis_info * vi)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 
_ve_envelope_clear(envelope_lookup * e)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 
_ve_amp(envelope_lookup * ve,vorbis_info_psy_global * gi,float * data,envelope_band * bands,envelope_filter_state * filters)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 n=ve->winlength;
96   int ret=0;
97   long i,j;
98   float decay;
99 
100   /* we want to have a 'minimum bar' for energy, else we're just
101      basing blocks on quantization noise that outweighs the signal
102      itself (for low power signals) */
103 
104   float minV=ve->minenergy;
105   float *vec=alloca(n*sizeof(*vec));
106 
107   /* stretch is used to gradually lengthen the number of windows
108      considered prevoius-to-potential-trigger */
109   int stretch=max(VE_MINSTRETCH,ve->stretch/2);
110   float penalty=gi->stretch_penalty-(ve->stretch/2-VE_MINSTRETCH);
111   if(penalty<0.f)penalty=0.f;
112   if(penalty>gi->stretch_penalty)penalty=gi->stretch_penalty;
113 
114   /*_analysis_output_always("lpcm",seq2,data,n,0,0,
115     totalshift+pos*ve->searchstep);*/
116 
117  /* window and transform */
118   for(i=0;i<n;i++)
119     vec[i]=data[i]*ve->mdct_win[i];
120   mdct_forward(&ve->mdct,vec,vec);
121 
122   /*_analysis_output_always("mdct",seq2,vec,n/2,0,1,0); */
123 
124   /* near-DC spreading function; this has nothing to do with
125      psychoacoustics, just sidelobe leakage and window size */
126   {
127     float temp=vec[0]*vec[0]+.7*vec[1]*vec[1]+.2*vec[2]*vec[2];
128     int ptr=filters->nearptr;
129 
130     /* the accumulation is regularly refreshed from scratch to avoid
131        floating point creep */
132     if(ptr==0){
133       decay=filters->nearDC_acc=filters->nearDC_partialacc+temp;
134       filters->nearDC_partialacc=temp;
135     }else{
136       decay=filters->nearDC_acc+=temp;
137       filters->nearDC_partialacc+=temp;
138     }
139     filters->nearDC_acc-=filters->nearDC[ptr];
140     filters->nearDC[ptr]=temp;
141 
142     decay*=(1./(VE_NEARDC+1));
143     filters->nearptr++;
144     if(filters->nearptr>=VE_NEARDC)filters->nearptr=0;
145     decay=todB(&decay)*.5-15.f;
146   }
147 
148   /* perform spreading and limiting, also smooth the spectrum.  yes,
149      the MDCT results in all real coefficients, but it still *behaves*
150      like real/imaginary pairs */
151   for(i=0;i<n/2;i+=2){
152     float val=vec[i]*vec[i]+vec[i+1]*vec[i+1];
153     val=todB(&val)*.5f;
154     if(val<decay)val=decay;
155     if(val<minV)val=minV;
156     vec[i>>1]=val;
157     decay-=8.;
158   }
159 
160   /*_analysis_output_always("spread",seq2++,vec,n/4,0,0,0);*/
161 
162   /* perform preecho/postecho triggering by band */
163   for(j=0;j<VE_BANDS;j++){
164     float acc=0.;
165     float valmax,valmin;
166 
167     /* accumulate amplitude */
168     for(i=0;i<bands[j].end;i++)
169       acc+=vec[i+bands[j].begin]*bands[j].window[i];
170 
171     acc*=bands[j].total;
172 
173     /* convert amplitude to delta */
174     {
175       int p,this=filters[j].ampptr;
176       float postmax,postmin,premax=-99999.f,premin=99999.f;
177 
178       p=this;
179       p--;
180       if(p<0)p+=VE_AMP;
181       postmax=max(acc,filters[j].ampbuf[p]);
182       postmin=min(acc,filters[j].ampbuf[p]);
183 
184       for(i=0;i<stretch;i++){
185         p--;
186         if(p<0)p+=VE_AMP;
187         premax=max(premax,filters[j].ampbuf[p]);
188         premin=min(premin,filters[j].ampbuf[p]);
189       }
190 
191       valmin=postmin-premin;
192       valmax=postmax-premax;
193 
194       /*filters[j].markers[pos]=valmax;*/
195       filters[j].ampbuf[this]=acc;
196       filters[j].ampptr++;
197       if(filters[j].ampptr>=VE_AMP)filters[j].ampptr=0;
198     }
199 
200     /* look at min/max, decide trigger */
201     if(valmax>gi->preecho_thresh[j]+penalty){
202       ret|=1;
203       ret|=4;
204     }
205     if(valmin<gi->postecho_thresh[j]-penalty)ret|=2;
206   }
207 
208   return(ret);
209 }
210 
211 #if 0
212 static int seq=0;
213 static ogg_int64_t totalshift=-1024;
214 #endif
215 
_ve_envelope_search(vorbis_dsp_state * v)216 long _ve_envelope_search(vorbis_dsp_state *v){
217   vorbis_info *vi=v->vi;
218   codec_setup_info *ci=vi->codec_setup;
219   vorbis_info_psy_global *gi=&ci->psy_g_param;
220   envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
221   long i,j;
222 
223   int first=ve->current/ve->searchstep;
224   int last=v->pcm_current/ve->searchstep-VE_WIN;
225   if(first<0)first=0;
226 
227   /* make sure we have enough storage to match the PCM */
228   if(last+VE_WIN+VE_POST>ve->storage){
229     ve->storage=last+VE_WIN+VE_POST; /* be sure */
230     ve->mark=_ogg_realloc(ve->mark,ve->storage*sizeof(*ve->mark));
231   }
232 
233   for(j=first;j<last;j++){
234     int ret=0;
235 
236     ve->stretch++;
237     if(ve->stretch>VE_MAXSTRETCH*2)
238       ve->stretch=VE_MAXSTRETCH*2;
239 
240     for(i=0;i<ve->ch;i++){
241       float *pcm=v->pcm[i]+ve->searchstep*(j);
242       ret|=_ve_amp(ve,gi,pcm,ve->band,ve->filter+i*VE_BANDS);
243     }
244 
245     ve->mark[j+VE_POST]=0;
246     if(ret&1){
247       ve->mark[j]=1;
248       ve->mark[j+1]=1;
249     }
250 
251     if(ret&2){
252       ve->mark[j]=1;
253       if(j>0)ve->mark[j-1]=1;
254     }
255 
256     if(ret&4)ve->stretch=-1;
257   }
258 
259   ve->current=last*ve->searchstep;
260 
261   {
262     long centerW=v->centerW;
263     long testW=
264       centerW+
265       ci->blocksizes[v->W]/4+
266       ci->blocksizes[1]/2+
267       ci->blocksizes[0]/4;
268 
269     j=ve->cursor;
270 
271     while(j<ve->current-(ve->searchstep)){/* account for postecho
272                                              working back one window */
273       if(j>=testW)return(1);
274 
275       ve->cursor=j;
276 
277       if(ve->mark[j/ve->searchstep]){
278         if(j>centerW){
279 
280 #if 0
281           if(j>ve->curmark){
282             float *marker=alloca(v->pcm_current*sizeof(*marker));
283             int l,m;
284             memset(marker,0,sizeof(*marker)*v->pcm_current);
285             fprintf(stderr,"mark! seq=%d, cursor:%fs time:%fs\n",
286                     seq,
287                     (totalshift+ve->cursor)/44100.,
288                     (totalshift+j)/44100.);
289             _analysis_output_always("pcmL",seq,v->pcm[0],v->pcm_current,0,0,totalshift);
290             _analysis_output_always("pcmR",seq,v->pcm[1],v->pcm_current,0,0,totalshift);
291 
292             _analysis_output_always("markL",seq,v->pcm[0],j,0,0,totalshift);
293             _analysis_output_always("markR",seq,v->pcm[1],j,0,0,totalshift);
294 
295             for(m=0;m<VE_BANDS;m++){
296               char buf[80];
297               sprintf(buf,"delL%d",m);
298               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m].markers[l]*.1;
299               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
300             }
301 
302             for(m=0;m<VE_BANDS;m++){
303               char buf[80];
304               sprintf(buf,"delR%d",m);
305               for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->filter[m+VE_BANDS].markers[l]*.1;
306               _analysis_output_always(buf,seq,marker,v->pcm_current,0,0,totalshift);
307             }
308 
309             for(l=0;l<last;l++)marker[l*ve->searchstep]=ve->mark[l]*.4;
310             _analysis_output_always("mark",seq,marker,v->pcm_current,0,0,totalshift);
311 
312 
313             seq++;
314 
315           }
316 #endif
317 
318           ve->curmark=j;
319           if(j>=testW)return(1);
320           return(0);
321         }
322       }
323       j+=ve->searchstep;
324     }
325   }
326 
327   return(-1);
328 }
329 
_ve_envelope_mark(vorbis_dsp_state * v)330 int _ve_envelope_mark(vorbis_dsp_state *v){
331   envelope_lookup *ve=((private_state *)(v->backend_state))->ve;
332   vorbis_info *vi=v->vi;
333   codec_setup_info *ci=vi->codec_setup;
334   long centerW=v->centerW;
335   long beginW=centerW-ci->blocksizes[v->W]/4;
336   long endW=centerW+ci->blocksizes[v->W]/4;
337   if(v->W){
338     beginW-=ci->blocksizes[v->lW]/4;
339     endW+=ci->blocksizes[v->nW]/4;
340   }else{
341     beginW-=ci->blocksizes[0]/4;
342     endW+=ci->blocksizes[0]/4;
343   }
344 
345   if(ve->curmark>=beginW && ve->curmark<endW)return(1);
346   {
347     long first=beginW/ve->searchstep;
348     long last=endW/ve->searchstep;
349     long i;
350     for(i=first;i<last;i++)
351       if(ve->mark[i])return(1);
352   }
353   return(0);
354 }
355 
_ve_envelope_shift(envelope_lookup * e,long shift)356 void _ve_envelope_shift(envelope_lookup *e,long shift){
357   int smallsize=e->current/e->searchstep+VE_POST; /* adjust for placing marks
358                                                      ahead of ve->current */
359   int smallshift=shift/e->searchstep;
360 
361   memmove(e->mark,e->mark+smallshift,(smallsize-smallshift)*sizeof(*e->mark));
362 
363 #if 0
364   for(i=0;i<VE_BANDS*e->ch;i++)
365     memmove(e->filter[i].markers,
366             e->filter[i].markers+smallshift,
367             (1024-smallshift)*sizeof(*(*e->filter).markers));
368   totalshift+=shift;
369 #endif
370 
371   e->current-=shift;
372   if(e->curmark>=0)
373     e->curmark-=shift;
374   e->cursor-=shift;
375 }
376