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;
99 floor0_free_info(info);
103 /* initialize Bark scale and normalization lookups. We could do this
104 with static tables, but Vorbis allows a number of possible
105 combinations, so it's best to do it computationally.
107 The below is authoritative in terms of defining scale mapping.
108 Note that the scale depends on the sampling rate as well as the
109 linear block and mapping sizes */
111 static void floor0_map_lazy_init(vorbis_block *vb,
112 vorbis_info_floor *infoX,
113 vorbis_look_floor0 *look){
114 if(!look->linearmap[vb->W]){
115 vorbis_dsp_state *vd=vb->vd;
116 vorbis_info *vi=vd->vi;
117 codec_setup_info *ci=vi->codec_setup;
118 vorbis_info_floor0 *info=(vorbis_info_floor0 *)infoX;
120 int n=ci->blocksizes[W]/2,j;
122 /* we choose a scaling constant so that:
123 floor(bark(rate/2-1)*C)=mapped-1
124 floor(bark(rate/2)*C)=mapped */
125 float scale=look->ln/toBARK(info->rate/2.f);
127 /* the mapping from a linear scale to a smaller bark scale is
128 straightforward. We do *not* make sure that the linear mapping
129 does not skip bark-scale bins; the decoder simply skips them and
130 the encoder may do what it wishes in filling them. They're
131 necessary in some mapping combinations to keep the scale spacing
133 look->linearmap[W]=_ogg_malloc((n+1)*sizeof(**look->linearmap));
135 int val=floor( toBARK((info->rate/2.f)/n*j)
136 *scale); /* bark numbers represent band edges */
137 if(val>=look->ln)val=look->ln-1; /* guard against the approximation */
138 look->linearmap[W][j]=val;
140 look->linearmap[W][j]=-1;
145 static vorbis_look_floor *floor0_look(vorbis_dsp_state *vd,
146 vorbis_info_floor *i){
147 vorbis_info_floor0 *info=(vorbis_info_floor0 *)i;
148 vorbis_look_floor0 *look=_ogg_calloc(1,sizeof(*look));
150 look->ln=info->barkmap;
153 look->linearmap=_ogg_calloc(2,sizeof(*look->linearmap));
158 static void *floor0_inverse1(vorbis_block *vb,vorbis_look_floor *i){
159 vorbis_look_floor0 *look=(vorbis_look_floor0 *)i;
160 vorbis_info_floor0 *info=look->vi;
163 int ampraw=oggpack_read(&vb->opb,info->ampbits);
164 if(ampraw>0){ /* also handles the -1 out of data case */
165 long maxval=(1<<info->ampbits)-1;
166 float amp=(float)ampraw/maxval*info->ampdB;
167 int booknum=oggpack_read(&vb->opb,_ilog(info->numbooks));
169 if(booknum!=-1 && booknum<info->numbooks){ /* be paranoid */
170 codec_setup_info *ci=vb->vd->vi->codec_setup;
171 codebook *b=ci->fullbooks+info->books[booknum];
174 /* the additional b->dim is a guard against any possible stack
175 smash; b->dim is provably more than we can overflow the
177 float *lsp=_vorbis_block_alloc(vb,sizeof(*lsp)*(look->m+b->dim+1));
179 for(j=0;j<look->m;j+=b->dim)
180 if(vorbis_book_decodev_set(b,lsp+j,&vb->opb,b->dim)==-1)goto eop;
182 for(k=0;k<b->dim;k++,j++)lsp[j]+=last;
194 static int floor0_inverse2(vorbis_block *vb,vorbis_look_floor *i,
195 void *memo,float *out){
196 vorbis_look_floor0 *look=(vorbis_look_floor0 *)i;
197 vorbis_info_floor0 *info=look->vi;
199 floor0_map_lazy_init(vb,info,look);
202 float *lsp=(float *)memo;
203 float amp=lsp[look->m];
205 /* take the coefficients back to a spectral envelope curve */
206 vorbis_lsp_to_curve(out,
207 look->linearmap[vb->W],
210 lsp,look->m,amp,(float)info->ampdB);
213 memset(out,0,sizeof(*out)*look->n[vb->W]);
218 const vorbis_func_floor floor0_exportbundle={
219 NULL,&floor0_unpack,&floor0_look,&floor0_free_info,
220 &floor0_free_look,&floor0_inverse1,&floor0_inverse2