added minimum turn option, to discretize turns in VR
[laserbrain_demo] / libs / vorbis / bitrate.c
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 1994-2009             *
9  * by the Xiph.Org Foundation http://www.xiph.org/                  *
10  *                                                                  *
11  ********************************************************************
12
13  function: bitrate tracking and management
14  last mod: $Id: bitrate.c 16227 2009-07-08 06:58:46Z xiphmont $
15
16  ********************************************************************/
17
18 #include <stdlib.h>
19 #include <string.h>
20 #include <math.h>
21 #include <ogg/ogg.h>
22 #include "vorbis/codec.h"
23 #include "codec_internal.h"
24 #include "os.h"
25 #include "misc.h"
26 #include "bitrate.h"
27
28 /* compute bitrate tracking setup  */
29 void vorbis_bitrate_init(vorbis_info *vi,bitrate_manager_state *bm){
30   codec_setup_info *ci=vi->codec_setup;
31   bitrate_manager_info *bi=&ci->bi;
32
33   memset(bm,0,sizeof(*bm));
34
35   if(bi && (bi->reservoir_bits>0)){
36     long ratesamples=vi->rate;
37     int  halfsamples=ci->blocksizes[0]>>1;
38
39     bm->short_per_long=ci->blocksizes[1]/ci->blocksizes[0];
40     bm->managed=1;
41
42     bm->avg_bitsper= rint(1.*bi->avg_rate*halfsamples/ratesamples);
43     bm->min_bitsper= rint(1.*bi->min_rate*halfsamples/ratesamples);
44     bm->max_bitsper= rint(1.*bi->max_rate*halfsamples/ratesamples);
45
46     bm->avgfloat=PACKETBLOBS/2;
47
48     /* not a necessary fix, but one that leads to a more balanced
49        typical initialization */
50     {
51       long desired_fill=bi->reservoir_bits*bi->reservoir_bias;
52       bm->minmax_reservoir=desired_fill;
53       bm->avg_reservoir=desired_fill;
54     }
55
56   }
57 }
58
59 void vorbis_bitrate_clear(bitrate_manager_state *bm){
60   memset(bm,0,sizeof(*bm));
61   return;
62 }
63
64 int vorbis_bitrate_managed(vorbis_block *vb){
65   vorbis_dsp_state      *vd=vb->vd;
66   private_state         *b=vd->backend_state;
67   bitrate_manager_state *bm=&b->bms;
68
69   if(bm && bm->managed)return(1);
70   return(0);
71 }
72
73 /* finish taking in the block we just processed */
74 int vorbis_bitrate_addblock(vorbis_block *vb){
75   vorbis_block_internal *vbi=vb->internal;
76   vorbis_dsp_state      *vd=vb->vd;
77   private_state         *b=vd->backend_state;
78   bitrate_manager_state *bm=&b->bms;
79   vorbis_info           *vi=vd->vi;
80   codec_setup_info      *ci=vi->codec_setup;
81   bitrate_manager_info  *bi=&ci->bi;
82
83   int  choice=rint(bm->avgfloat);
84   long this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
85   long min_target_bits=(vb->W?bm->min_bitsper*bm->short_per_long:bm->min_bitsper);
86   long max_target_bits=(vb->W?bm->max_bitsper*bm->short_per_long:bm->max_bitsper);
87   int  samples=ci->blocksizes[vb->W]>>1;
88   long desired_fill=bi->reservoir_bits*bi->reservoir_bias;
89   if(!bm->managed){
90     /* not a bitrate managed stream, but for API simplicity, we'll
91        buffer the packet to keep the code path clean */
92
93     if(bm->vb)return(-1); /* one has been submitted without
94                              being claimed */
95     bm->vb=vb;
96     return(0);
97   }
98
99   bm->vb=vb;
100
101   /* look ahead for avg floater */
102   if(bm->avg_bitsper>0){
103     double slew=0.;
104     long avg_target_bits=(vb->W?bm->avg_bitsper*bm->short_per_long:bm->avg_bitsper);
105     double slewlimit= 15./bi->slew_damp;
106
107     /* choosing a new floater:
108        if we're over target, we slew down
109        if we're under target, we slew up
110
111        choose slew as follows: look through packetblobs of this frame
112        and set slew as the first in the appropriate direction that
113        gives us the slew we want.  This may mean no slew if delta is
114        already favorable.
115
116        Then limit slew to slew max */
117
118     if(bm->avg_reservoir+(this_bits-avg_target_bits)>desired_fill){
119       while(choice>0 && this_bits>avg_target_bits &&
120             bm->avg_reservoir+(this_bits-avg_target_bits)>desired_fill){
121         choice--;
122         this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
123       }
124     }else if(bm->avg_reservoir+(this_bits-avg_target_bits)<desired_fill){
125       while(choice+1<PACKETBLOBS && this_bits<avg_target_bits &&
126             bm->avg_reservoir+(this_bits-avg_target_bits)<desired_fill){
127         choice++;
128         this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
129       }
130     }
131
132     slew=rint(choice-bm->avgfloat)/samples*vi->rate;
133     if(slew<-slewlimit)slew=-slewlimit;
134     if(slew>slewlimit)slew=slewlimit;
135     choice=rint(bm->avgfloat+= slew/vi->rate*samples);
136     this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
137   }
138
139
140
141   /* enforce min(if used) on the current floater (if used) */
142   if(bm->min_bitsper>0){
143     /* do we need to force the bitrate up? */
144     if(this_bits<min_target_bits){
145       while(bm->minmax_reservoir-(min_target_bits-this_bits)<0){
146         choice++;
147         if(choice>=PACKETBLOBS)break;
148         this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
149       }
150     }
151   }
152
153   /* enforce max (if used) on the current floater (if used) */
154   if(bm->max_bitsper>0){
155     /* do we need to force the bitrate down? */
156     if(this_bits>max_target_bits){
157       while(bm->minmax_reservoir+(this_bits-max_target_bits)>bi->reservoir_bits){
158         choice--;
159         if(choice<0)break;
160         this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
161       }
162     }
163   }
164
165   /* Choice of packetblobs now made based on floater, and min/max
166      requirements. Now boundary check extreme choices */
167
168   if(choice<0){
169     /* choosing a smaller packetblob is insufficient to trim bitrate.
170        frame will need to be truncated */
171     long maxsize=(max_target_bits+(bi->reservoir_bits-bm->minmax_reservoir))/8;
172     bm->choice=choice=0;
173
174     if(oggpack_bytes(vbi->packetblob[choice])>maxsize){
175
176       oggpack_writetrunc(vbi->packetblob[choice],maxsize*8);
177       this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
178     }
179   }else{
180     long minsize=(min_target_bits-bm->minmax_reservoir+7)/8;
181     if(choice>=PACKETBLOBS)
182       choice=PACKETBLOBS-1;
183
184     bm->choice=choice;
185
186     /* prop up bitrate according to demand. pad this frame out with zeroes */
187     minsize-=oggpack_bytes(vbi->packetblob[choice]);
188     while(minsize-->0)oggpack_write(vbi->packetblob[choice],0,8);
189     this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
190
191   }
192
193   /* now we have the final packet and the final packet size.  Update statistics */
194   /* min and max reservoir */
195   if(bm->min_bitsper>0 || bm->max_bitsper>0){
196
197     if(max_target_bits>0 && this_bits>max_target_bits){
198       bm->minmax_reservoir+=(this_bits-max_target_bits);
199     }else if(min_target_bits>0 && this_bits<min_target_bits){
200       bm->minmax_reservoir+=(this_bits-min_target_bits);
201     }else{
202       /* inbetween; we want to take reservoir toward but not past desired_fill */
203       if(bm->minmax_reservoir>desired_fill){
204         if(max_target_bits>0){ /* logical bulletproofing against initialization state */
205           bm->minmax_reservoir+=(this_bits-max_target_bits);
206           if(bm->minmax_reservoir<desired_fill)bm->minmax_reservoir=desired_fill;
207         }else{
208           bm->minmax_reservoir=desired_fill;
209         }
210       }else{
211         if(min_target_bits>0){ /* logical bulletproofing against initialization state */
212           bm->minmax_reservoir+=(this_bits-min_target_bits);
213           if(bm->minmax_reservoir>desired_fill)bm->minmax_reservoir=desired_fill;
214         }else{
215           bm->minmax_reservoir=desired_fill;
216         }
217       }
218     }
219   }
220
221   /* avg reservoir */
222   if(bm->avg_bitsper>0){
223     long avg_target_bits=(vb->W?bm->avg_bitsper*bm->short_per_long:bm->avg_bitsper);
224     bm->avg_reservoir+=this_bits-avg_target_bits;
225   }
226
227   return(0);
228 }
229
230 int vorbis_bitrate_flushpacket(vorbis_dsp_state *vd,ogg_packet *op){
231   private_state         *b=vd->backend_state;
232   bitrate_manager_state *bm=&b->bms;
233   vorbis_block          *vb=bm->vb;
234   int                    choice=PACKETBLOBS/2;
235   if(!vb)return 0;
236
237   if(op){
238     vorbis_block_internal *vbi=vb->internal;
239
240     if(vorbis_bitrate_managed(vb))
241       choice=bm->choice;
242
243     op->packet=oggpack_get_buffer(vbi->packetblob[choice]);
244     op->bytes=oggpack_bytes(vbi->packetblob[choice]);
245     op->b_o_s=0;
246     op->e_o_s=vb->eofflag;
247     op->granulepos=vb->granulepos;
248     op->packetno=vb->sequence; /* for sake of completeness */
249   }
250
251   bm->vb=0;
252   return(1);
253 }