mirror of
https://github.com/Relintai/pandemonium_engine.git
synced 2024-12-24 04:46:48 +01:00
120 lines
5.1 KiB
C
120 lines
5.1 KiB
C
/********************************************************************
|
|
* *
|
|
* THIS FILE IS PART OF THE OggTheora 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 Theora SOURCE CODE IS COPYRIGHT (C) 2002-2009 *
|
|
* by the Xiph.Org Foundation and contributors http://www.xiph.org/ *
|
|
* *
|
|
********************************************************************
|
|
|
|
function:
|
|
last mod: $Id: quant.c 16503 2009-08-22 18:14:02Z giles $
|
|
|
|
********************************************************************/
|
|
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <ogg/ogg.h>
|
|
#include "quant.h"
|
|
#include "decint.h"
|
|
|
|
static const unsigned OC_DC_QUANT_MIN[2]={4<<2,8<<2};
|
|
static const unsigned OC_AC_QUANT_MIN[2]={2<<2,4<<2};
|
|
|
|
/*Initializes the dequantization tables from a set of quantizer info.
|
|
Currently the dequantizer (and elsewhere enquantizer) tables are expected to
|
|
be initialized as pointing to the storage reserved for them in the
|
|
oc_theora_state (resp. oc_enc_ctx) structure.
|
|
If some tables are duplicates of others, the pointers will be adjusted to
|
|
point to a single copy of the tables, but the storage for them will not be
|
|
freed.
|
|
If you're concerned about the memory footprint, the obvious thing to do is
|
|
to move the storage out of its fixed place in the structures and allocate
|
|
it on demand.
|
|
However, a much, much better option is to only store the quantization
|
|
matrices being used for the current frame, and to recalculate these as the
|
|
qi values change between frames (this is what VP3 did).*/
|
|
void oc_dequant_tables_init(ogg_uint16_t *_dequant[64][3][2],
|
|
int _pp_dc_scale[64],const th_quant_info *_qinfo){
|
|
/*Coding mode: intra or inter.*/
|
|
int qti;
|
|
/*Y', C_b, C_r*/
|
|
int pli;
|
|
for(qti=0;qti<2;qti++)for(pli=0;pli<3;pli++){
|
|
/*Quality index.*/
|
|
int qi;
|
|
/*Range iterator.*/
|
|
int qri;
|
|
for(qi=0,qri=0;qri<=_qinfo->qi_ranges[qti][pli].nranges;qri++){
|
|
th_quant_base base;
|
|
ogg_uint32_t q;
|
|
int qi_start;
|
|
int qi_end;
|
|
memcpy(base,_qinfo->qi_ranges[qti][pli].base_matrices[qri],
|
|
sizeof(base));
|
|
qi_start=qi;
|
|
if(qri==_qinfo->qi_ranges[qti][pli].nranges)qi_end=qi+1;
|
|
else qi_end=qi+_qinfo->qi_ranges[qti][pli].sizes[qri];
|
|
/*Iterate over quality indicies in this range.*/
|
|
for(;;){
|
|
ogg_uint32_t qfac;
|
|
int zzi;
|
|
int ci;
|
|
/*In the original VP3.2 code, the rounding offset and the size of the
|
|
dead zone around 0 were controlled by a "sharpness" parameter.
|
|
The size of our dead zone is now controlled by the per-coefficient
|
|
quality thresholds returned by our HVS module.
|
|
We round down from a more accurate value when the quality of the
|
|
reconstruction does not fall below our threshold and it saves bits.
|
|
Hence, all of that VP3.2 code is gone from here, and the remaining
|
|
floating point code has been implemented as equivalent integer code
|
|
with exact precision.*/
|
|
qfac=(ogg_uint32_t)_qinfo->dc_scale[qi]*base[0];
|
|
/*For postprocessing, not dequantization.*/
|
|
if(_pp_dc_scale!=NULL)_pp_dc_scale[qi]=(int)(qfac/160);
|
|
/*Scale DC the coefficient from the proper table.*/
|
|
q=(qfac/100)<<2;
|
|
q=OC_CLAMPI(OC_DC_QUANT_MIN[qti],q,OC_QUANT_MAX);
|
|
_dequant[qi][pli][qti][0]=(ogg_uint16_t)q;
|
|
/*Now scale AC coefficients from the proper table.*/
|
|
for(zzi=1;zzi<64;zzi++){
|
|
q=((ogg_uint32_t)_qinfo->ac_scale[qi]*base[OC_FZIG_ZAG[zzi]]/100)<<2;
|
|
q=OC_CLAMPI(OC_AC_QUANT_MIN[qti],q,OC_QUANT_MAX);
|
|
_dequant[qi][pli][qti][zzi]=(ogg_uint16_t)q;
|
|
}
|
|
/*If this is a duplicate of a previous matrix, use that instead.
|
|
This simple check helps us improve cache coherency later.*/
|
|
{
|
|
int dupe;
|
|
int qtj;
|
|
int plj;
|
|
dupe=0;
|
|
for(qtj=0;qtj<=qti;qtj++){
|
|
for(plj=0;plj<(qtj<qti?3:pli);plj++){
|
|
if(!memcmp(_dequant[qi][pli][qti],_dequant[qi][plj][qtj],
|
|
sizeof(oc_quant_table))){
|
|
dupe=1;
|
|
break;
|
|
}
|
|
}
|
|
if(dupe)break;
|
|
}
|
|
if(dupe)_dequant[qi][pli][qti]=_dequant[qi][plj][qtj];
|
|
}
|
|
if(++qi>=qi_end)break;
|
|
/*Interpolate the next base matrix.*/
|
|
for(ci=0;ci<64;ci++){
|
|
base[ci]=(unsigned char)(
|
|
(2*((qi_end-qi)*_qinfo->qi_ranges[qti][pli].base_matrices[qri][ci]+
|
|
(qi-qi_start)*_qinfo->qi_ranges[qti][pli].base_matrices[qri+1][ci])
|
|
+_qinfo->qi_ranges[qti][pli].sizes[qri])/
|
|
(2*_qinfo->qi_ranges[qti][pli].sizes[qri]));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|