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: floor backend 0 implementation
16 ********************************************************************/
22 #include "vorbis/codec.h"
23 #include "codec_internal.h"
41 vorbis_info_floor0 *vi;
48 /***********************************************/
50 static void floor0_free_info(vorbis_info_floor *i){
51 vorbis_info_floor0 *info=(vorbis_info_floor0 *)i;
53 memset(info,0,sizeof(*info));
58 static void floor0_free_look(vorbis_look_floor *i){
59 vorbis_look_floor0 *look=(vorbis_look_floor0 *)i;
64 if(look->linearmap[0])_ogg_free(look->linearmap[0]);
65 if(look->linearmap[1])_ogg_free(look->linearmap[1]);
67 _ogg_free(look->linearmap);
69 memset(look,0,sizeof(*look));
74 static vorbis_info_floor *floor0_unpack (vorbis_info *vi,oggpack_buffer *opb){
75 codec_setup_info *ci=vi->codec_setup;
78 vorbis_info_floor0 *info=_ogg_malloc(sizeof(*info));
79 info->order=oggpack_read(opb,8);
80 info->rate=oggpack_read(opb,16);
81 info->barkmap=oggpack_read(opb,16);
82 info->ampbits=oggpack_read(opb,6);
83 info->ampdB=oggpack_read(opb,8);
84 info->numbooks=oggpack_read(opb,4)+1;
86 if(info->order<1)goto err_out;
87 if(info->rate<1)goto err_out;
88 if(info->barkmap<1)goto err_out;
89 if(info->numbooks<1)goto err_out;
91 for(j=0;j<info->numbooks;j++){
92 info->books[j]=oggpack_read(opb,8);
93 if(info->books[j]<0 || info->books[j]>=ci->books)goto err_out;
94 if(ci->book_param[info->books[j]]->maptype==0)goto err_out;
95 if(ci->book_param[info->books[j]]->dim<1)goto err_out;
100 floor0_free_info(info);
104 /* initialize Bark scale and normalization lookups. We could do this
105 with static tables, but Vorbis allows a number of possible
106 combinations, so it's best to do it computationally.
108 The below is authoritative in terms of defining scale mapping.
109 Note that the scale depends on the sampling rate as well as the
110 linear block and mapping sizes */
112 static void floor0_map_lazy_init(vorbis_block *vb,
113 vorbis_info_floor *infoX,
114 vorbis_look_floor0 *look){
115 if(!look->linearmap[vb->W]){
116 vorbis_dsp_state *vd=vb->vd;
117 vorbis_info *vi=vd->vi;
118 codec_setup_info *ci=vi->codec_setup;
119 vorbis_info_floor0 *info=(vorbis_info_floor0 *)infoX;
121 int n=ci->blocksizes[W]/2,j;
123 /* we choose a scaling constant so that:
124 floor(bark(rate/2-1)*C)=mapped-1
125 floor(bark(rate/2)*C)=mapped */
126 float scale=look->ln/toBARK(info->rate/2.f);
128 /* the mapping from a linear scale to a smaller bark scale is
129 straightforward. We do *not* make sure that the linear mapping
130 does not skip bark-scale bins; the decoder simply skips them and
131 the encoder may do what it wishes in filling them. They're
132 necessary in some mapping combinations to keep the scale spacing
134 look->linearmap[W]=_ogg_malloc((n+1)*sizeof(**look->linearmap));
136 int val=floor( toBARK((info->rate/2.f)/n*j)
137 *scale); /* bark numbers represent band edges */
138 if(val>=look->ln)val=look->ln-1; /* guard against the approximation */
139 look->linearmap[W][j]=val;
141 look->linearmap[W][j]=-1;
146 static vorbis_look_floor *floor0_look(vorbis_dsp_state *vd,
147 vorbis_info_floor *i){
148 vorbis_info_floor0 *info=(vorbis_info_floor0 *)i;
149 vorbis_look_floor0 *look=_ogg_calloc(1,sizeof(*look));
154 look->ln=info->barkmap;
157 look->linearmap=_ogg_calloc(2,sizeof(*look->linearmap));
162 static void *floor0_inverse1(vorbis_block *vb,vorbis_look_floor *i){
163 vorbis_look_floor0 *look=(vorbis_look_floor0 *)i;
164 vorbis_info_floor0 *info=look->vi;
167 int ampraw=oggpack_read(&vb->opb,info->ampbits);
168 if(ampraw>0){ /* also handles the -1 out of data case */
169 long maxval=(1<<info->ampbits)-1;
170 float amp=(float)ampraw/maxval*info->ampdB;
171 int booknum=oggpack_read(&vb->opb,_ilog(info->numbooks));
173 if(booknum!=-1 && booknum<info->numbooks){ /* be paranoid */
174 codec_setup_info *ci=vb->vd->vi->codec_setup;
175 codebook *b=ci->fullbooks+info->books[booknum];
178 /* the additional b->dim is a guard against any possible stack
179 smash; b->dim is provably more than we can overflow the
181 float *lsp=_vorbis_block_alloc(vb,sizeof(*lsp)*(look->m+b->dim+1));
183 if(vorbis_book_decodev_set(b,lsp,&vb->opb,look->m)==-1)goto eop;
185 for(k=0;j<look->m && k<b->dim;k++,j++)lsp[j]+=last;
197 static int floor0_inverse2(vorbis_block *vb,vorbis_look_floor *i,
198 void *memo,float *out){
199 vorbis_look_floor0 *look=(vorbis_look_floor0 *)i;
200 vorbis_info_floor0 *info=look->vi;
202 floor0_map_lazy_init(vb,info,look);
205 float *lsp=(float *)memo;
206 float amp=lsp[look->m];
208 /* take the coefficients back to a spectral envelope curve */
209 vorbis_lsp_to_curve(out,
210 look->linearmap[vb->W],
213 lsp,look->m,amp,(float)info->ampdB);
216 memset(out,0,sizeof(*out)*look->n[vb->W]);
221 const vorbis_func_floor floor0_exportbundle={
222 NULL,&floor0_unpack,&floor0_look,&floor0_free_info,
223 &floor0_free_look,&floor0_inverse1,&floor0_inverse2