rockbox/apps/codecs/Tremor/synthesis.c
Pedro Vasconcelos 6b9350b4d3 A little improvement on Vorbis block synthesis.
Added myself to the list of contributors.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@6664 a1c6a512-1295-4272-9138-f99709370657
2005-06-10 22:34:57 +00:00

132 lines
4 KiB
C

/********************************************************************
* *
* THIS FILE IS PART OF THE OggVorbis 'TREMOR' 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 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2003 *
* BY THE Xiph.Org FOUNDATION http://www.xiph.org/ *
* *
********************************************************************
function: single-block PCM synthesis
last mod: $Id$
********************************************************************/
#include <stdio.h>
#include "ogg.h"
#include "ivorbiscodec.h"
#include "codec_internal.h"
#include "registry.h"
#include "misc.h"
#include "os.h"
/* IRAM buffer keep the block pcm data; only for windows size upto 2048
for space restrictions.
libVorbis 1.1 Oggenc doesn't use larger windows anyway. */
/* max 2 channels on the ihp-1xx (stereo), 2048 samples (2*2048*4=16Kb) */
#define IRAM_PCM_END 2048
#define CHANNELS 2
static ogg_int32_t *ipcm_vect[CHANNELS] IDATA_ATTR;
static ogg_int32_t ipcm_buff[CHANNELS*IRAM_PCM_END] IDATA_ATTR LINE_ATTR;
int vorbis_synthesis(vorbis_block *vb,ogg_packet *op,int decodep){
vorbis_dsp_state *vd=vb->vd;
private_state *b=(private_state *)vd->backend_state;
vorbis_info *vi=vd->vi;
codec_setup_info *ci=(codec_setup_info *)vi->codec_setup;
oggpack_buffer *opb=&vb->opb;
int type,mode,i;
/* first things first. Make sure decode is ready */
_vorbis_block_ripcord(vb);
oggpack_readinit(opb,op->packet);
/* 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;
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-3; /* first block is third packet */
vb->eofflag=op->e_o_s;
if(decodep && vi->channels<=CHANNELS){
/* alloc pcm passback storage */
vb->pcmend=ci->blocksizes[vb->W];
if (vb->pcmend<=IRAM_PCM_END) {
/* use statically allocated iram buffer */
vb->pcm = ipcm_vect;
for(i=0; i<CHANNELS; i++)
vb->pcm[i] = &ipcm_buff[i*IRAM_PCM_END];
} else {
/* dynamic allocation (slower) */
vb->pcm=(ogg_int32_t **)_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels);
for(i=0;i<vi->channels;i++)
vb->pcm[i]=(ogg_int32_t *)_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,b->mode[mode]));
}else{
/* no pcm */
vb->pcmend=0;
vb->pcm=NULL;
return(0);
}
}
long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){
codec_setup_info *ci=(codec_setup_info *)vi->codec_setup;
oggpack_buffer opb;
int mode;
oggpack_readinit(&opb,op->packet);
/* Check the packet type */
if(oggpack_read(&opb,1)!=0){
/* Oops. This is not an audio data packet */
return(OV_ENOTAUDIO);
}
{
int modebits=0;
int v=ci->modes;
while(v>1){
modebits++;
v>>=1;
}
/* read our mode and pre/post windowsize */
mode=oggpack_read(&opb,modebits);
}
if(mode==-1)return(OV_EBADPACKET);
return(ci->blocksizes[ci->mode_param[mode]->blockflag]);
}