ref: 17f7f6be4e1a316c0f5f26ff70e047aece4de2bc
dir: /sys/src/cmd/audio/libvorbis/synthesis.c/
/******************************************************************** * * * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. * * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * * * * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2015 * * by the Xiph.Org Foundation https://xiph.org/ * * * ******************************************************************** function: single-block PCM synthesis ********************************************************************/ #include <stdio.h> #include <ogg/ogg.h> #include "vorbis/codec.h" #include "codec_internal.h" #include "registry.h" #include "misc.h" #include "os.h" int vorbis_synthesis(vorbis_block *vb,ogg_packet *op){ vorbis_dsp_state *vd= vb ? vb->vd : 0; private_state *b= vd ? vd->backend_state : 0; vorbis_info *vi= vd ? vd->vi : 0; codec_setup_info *ci= vi ? vi->codec_setup : 0; oggpack_buffer *opb=vb ? &vb->opb : 0; int type,mode,i; if (!vd || !b || !vi || !ci || !opb) { return OV_EBADPACKET; } /* first things first. Make sure decode is ready */ _vorbis_block_ripcord(vb); oggpack_readinit(opb,op->packet,op->bytes); /* Check the packet type */ if(oggpack_read(opb,1)!=0){ /* Oops. This is not an audio data packet */ return(OV_ENOTAUDIO); } /* read our mode and pre/post windowsize */ mode=oggpack_read(opb,b->modebits); if(mode==-1){ return(OV_EBADPACKET); } vb->mode=mode; if(!ci->mode_param[mode]){ return(OV_EBADPACKET); } vb->W=ci->mode_param[mode]->blockflag; if(vb->W){ /* this doesn;t get mapped through mode selection as it's used only for window selection */ vb->lW=oggpack_read(opb,1); vb->nW=oggpack_read(opb,1); if(vb->nW==-1){ return(OV_EBADPACKET); } }else{ vb->lW=0; vb->nW=0; } /* more setup */ vb->granulepos=op->granulepos; vb->sequence=op->packetno; vb->eofflag=op->e_o_s; /* alloc pcm passback storage */ vb->pcmend=ci->blocksizes[vb->W]; vb->pcm=_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels); for(i=0;i<vi->channels;i++) vb->pcm[i]=_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i])); /* unpack_header enforces range checking */ type=ci->map_type[ci->mode_param[mode]->mapping]; return(_mapping_P[type]->inverse(vb,ci->map_param[ci->mode_param[mode]-> mapping])); } /* used to track pcm position without actually performing decode. Useful for sequential 'fast forward' */ int vorbis_synthesis_trackonly(vorbis_block *vb,ogg_packet *op){ vorbis_dsp_state *vd=vb->vd; private_state *b=vd->backend_state; vorbis_info *vi=vd->vi; codec_setup_info *ci=vi->codec_setup; oggpack_buffer *opb=&vb->opb; int mode; /* first things first. Make sure decode is ready */ _vorbis_block_ripcord(vb); oggpack_readinit(opb,op->packet,op->bytes); /* Check the packet type */ if(oggpack_read(opb,1)!=0){ /* Oops. This is not an audio data packet */ return(OV_ENOTAUDIO); } /* read our mode and pre/post windowsize */ mode=oggpack_read(opb,b->modebits); if(mode==-1)return(OV_EBADPACKET); vb->mode=mode; if(!ci->mode_param[mode]){ return(OV_EBADPACKET); } vb->W=ci->mode_param[mode]->blockflag; if(vb->W){ vb->lW=oggpack_read(opb,1); vb->nW=oggpack_read(opb,1); if(vb->nW==-1) return(OV_EBADPACKET); }else{ vb->lW=0; vb->nW=0; } /* more setup */ vb->granulepos=op->granulepos; vb->sequence=op->packetno; vb->eofflag=op->e_o_s; /* no pcm */ vb->pcmend=0; vb->pcm=NULL; return(0); } long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){ codec_setup_info *ci=vi->codec_setup; oggpack_buffer opb; int mode; if(ci==NULL || ci->modes<=0){ /* codec setup not properly intialized */ return(OV_EFAULT); } oggpack_readinit(&opb,op->packet,op->bytes); /* Check the packet type */ if(oggpack_read(&opb,1)!=0){ /* Oops. This is not an audio data packet */ return(OV_ENOTAUDIO); } /* read our mode and pre/post windowsize */ mode=oggpack_read(&opb,ov_ilog(ci->modes-1)); if(mode==-1 || !ci->mode_param[mode])return(OV_EBADPACKET); return(ci->blocksizes[ci->mode_param[mode]->blockflag]); } int vorbis_synthesis_halfrate(vorbis_info *vi,int flag){ /* set / clear half-sample-rate mode */ codec_setup_info *ci=vi->codec_setup; /* right now, our MDCT can't handle < 64 sample windows. */ if(ci->blocksizes[0]<=64 && flag)return -1; ci->halfrate_flag=(flag?1:0); return 0; } int vorbis_synthesis_halfrate_p(vorbis_info *vi){ codec_setup_info *ci=vi->codec_setup; return ci->halfrate_flag; }