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275 lines
10 KiB
C
275 lines
10 KiB
C
/********************************************************************
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* *
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* THIS FILE IS PART OF THE OggTheora SOFTWARE CODEC SOURCE CODE. *
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* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
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* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
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* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
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* *
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* THE Theora SOURCE CODE IS COPYRIGHT (C) 2002-2009 *
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* by the Xiph.Org Foundation http://www.xiph.org/ *
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* *
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********************************************************************
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function:
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last mod: $Id: enquant.c 16503 2009-08-22 18:14:02Z giles $
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********************************************************************/
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#include <stdlib.h>
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#include <string.h>
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#include "encint.h"
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void oc_quant_params_pack(oggpack_buffer *_opb,const th_quant_info *_qinfo){
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const th_quant_ranges *qranges;
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const th_quant_base *base_mats[2*3*64];
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int indices[2][3][64];
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int nbase_mats;
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int nbits;
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int ci;
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int qi;
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int qri;
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int qti;
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int pli;
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int qtj;
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int plj;
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int bmi;
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int i;
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i=_qinfo->loop_filter_limits[0];
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for(qi=1;qi<64;qi++)i=OC_MAXI(i,_qinfo->loop_filter_limits[qi]);
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nbits=OC_ILOG_32(i);
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oggpackB_write(_opb,nbits,3);
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for(qi=0;qi<64;qi++){
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oggpackB_write(_opb,_qinfo->loop_filter_limits[qi],nbits);
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}
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/*580 bits for VP3.*/
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i=1;
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for(qi=0;qi<64;qi++)i=OC_MAXI(_qinfo->ac_scale[qi],i);
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nbits=OC_ILOGNZ_32(i);
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oggpackB_write(_opb,nbits-1,4);
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for(qi=0;qi<64;qi++)oggpackB_write(_opb,_qinfo->ac_scale[qi],nbits);
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/*516 bits for VP3.*/
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i=1;
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for(qi=0;qi<64;qi++)i=OC_MAXI(_qinfo->dc_scale[qi],i);
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nbits=OC_ILOGNZ_32(i);
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oggpackB_write(_opb,nbits-1,4);
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for(qi=0;qi<64;qi++)oggpackB_write(_opb,_qinfo->dc_scale[qi],nbits);
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/*Consolidate any duplicate base matrices.*/
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nbase_mats=0;
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for(qti=0;qti<2;qti++)for(pli=0;pli<3;pli++){
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qranges=_qinfo->qi_ranges[qti]+pli;
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for(qri=0;qri<=qranges->nranges;qri++){
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for(bmi=0;;bmi++){
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if(bmi>=nbase_mats){
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base_mats[bmi]=qranges->base_matrices+qri;
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indices[qti][pli][qri]=nbase_mats++;
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break;
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}
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else if(memcmp(base_mats[bmi][0],qranges->base_matrices[qri],
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sizeof(base_mats[bmi][0]))==0){
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indices[qti][pli][qri]=bmi;
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break;
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}
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}
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}
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}
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/*Write out the list of unique base matrices.
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1545 bits for VP3 matrices.*/
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oggpackB_write(_opb,nbase_mats-1,9);
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for(bmi=0;bmi<nbase_mats;bmi++){
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for(ci=0;ci<64;ci++)oggpackB_write(_opb,base_mats[bmi][0][ci],8);
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}
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/*Now store quant ranges and their associated indices into the base matrix
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list.
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46 bits for VP3 matrices.*/
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nbits=OC_ILOG_32(nbase_mats-1);
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for(i=0;i<6;i++){
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qti=i/3;
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pli=i%3;
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qranges=_qinfo->qi_ranges[qti]+pli;
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if(i>0){
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if(qti>0){
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if(qranges->nranges==_qinfo->qi_ranges[qti-1][pli].nranges&&
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memcmp(qranges->sizes,_qinfo->qi_ranges[qti-1][pli].sizes,
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qranges->nranges*sizeof(qranges->sizes[0]))==0&&
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memcmp(indices[qti][pli],indices[qti-1][pli],
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(qranges->nranges+1)*sizeof(indices[qti][pli][0]))==0){
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oggpackB_write(_opb,1,2);
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continue;
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}
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}
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qtj=(i-1)/3;
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plj=(i-1)%3;
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if(qranges->nranges==_qinfo->qi_ranges[qtj][plj].nranges&&
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memcmp(qranges->sizes,_qinfo->qi_ranges[qtj][plj].sizes,
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qranges->nranges*sizeof(qranges->sizes[0]))==0&&
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memcmp(indices[qti][pli],indices[qtj][plj],
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(qranges->nranges+1)*sizeof(indices[qti][pli][0]))==0){
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oggpackB_write(_opb,0,1+(qti>0));
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continue;
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}
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oggpackB_write(_opb,1,1);
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}
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oggpackB_write(_opb,indices[qti][pli][0],nbits);
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for(qi=qri=0;qi<63;qri++){
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oggpackB_write(_opb,qranges->sizes[qri]-1,OC_ILOG_32(62-qi));
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qi+=qranges->sizes[qri];
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oggpackB_write(_opb,indices[qti][pli][qri+1],nbits);
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}
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}
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}
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static void oc_iquant_init(oc_iquant *_this,ogg_uint16_t _d){
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ogg_uint32_t t;
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int l;
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_d<<=1;
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l=OC_ILOGNZ_32(_d)-1;
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t=1+((ogg_uint32_t)1<<16+l)/_d;
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_this->m=(ogg_int16_t)(t-0x10000);
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_this->l=l;
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}
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/*See comments at oc_dequant_tables_init() for how the quantization tables'
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storage should be initialized.*/
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void oc_enquant_tables_init(ogg_uint16_t *_dequant[64][3][2],
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oc_iquant *_enquant[64][3][2],const th_quant_info *_qinfo){
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int qi;
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int pli;
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int qti;
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/*Initialize the dequantization tables first.*/
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oc_dequant_tables_init(_dequant,NULL,_qinfo);
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/*Derive the quantization tables directly from the dequantization tables.*/
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for(qi=0;qi<64;qi++)for(qti=0;qti<2;qti++)for(pli=0;pli<3;pli++){
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int zzi;
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int plj;
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int qtj;
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int dupe;
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dupe=0;
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for(qtj=0;qtj<=qti;qtj++){
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for(plj=0;plj<(qtj<qti?3:pli);plj++){
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if(_dequant[qi][pli][qti]==_dequant[qi][plj][qtj]){
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dupe=1;
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break;
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}
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}
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if(dupe)break;
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}
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if(dupe){
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_enquant[qi][pli][qti]=_enquant[qi][plj][qtj];
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continue;
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}
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/*In the original VP3.2 code, the rounding offset and the size of the
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dead zone around 0 were controlled by a "sharpness" parameter.
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We now R-D optimize the tokens for each block after quantization,
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so the rounding offset should always be 1/2, and an explicit dead
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zone is unnecessary.
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Hence, all of that VP3.2 code is gone from here, and the remaining
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floating point code has been implemented as equivalent integer
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code with exact precision.*/
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for(zzi=0;zzi<64;zzi++){
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oc_iquant_init(_enquant[qi][pli][qti]+zzi,
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_dequant[qi][pli][qti][zzi]);
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}
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}
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}
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/*This table gives the square root of the fraction of the squared magnitude of
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each DCT coefficient relative to the total, scaled by 2**16, for both INTRA
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and INTER modes.
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These values were measured after motion-compensated prediction, before
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quantization, over a large set of test video (from QCIF to 1080p) encoded at
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all possible rates.
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The DC coefficient takes into account the DPCM prediction (using the
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quantized values from neighboring blocks, as the encoder does, but still
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before quantization of the coefficient in the current block).
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The results differ significantly from the expected variance (e.g., using an
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AR(1) model of the signal with rho=0.95, as is frequently done to compute
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the coding gain of the DCT).
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We use them to estimate an "average" quantizer for a given quantizer matrix,
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as this is used to parameterize a number of the rate control decisions.
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These values are themselves probably quantizer-matrix dependent, since the
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shape of the matrix affects the noise distribution in the reference frames,
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but they should at least give us _some_ amount of adaptivity to different
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matrices, as opposed to hard-coding a table of average Q values for the
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current set.
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The main features they capture are that a) only a few of the quantizers in
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the upper-left corner contribute anything significant at all (though INTER
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mode is significantly flatter) and b) the DPCM prediction of the DC
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coefficient gives a very minor improvement in the INTRA case and a quite
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significant one in the INTER case (over the expected variance).*/
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static const ogg_uint16_t OC_RPSD[2][64]={
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{
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52725,17370,10399, 6867, 5115, 3798, 2942, 2076,
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17370, 9900, 6948, 4994, 3836, 2869, 2229, 1619,
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10399, 6948, 5516, 4202, 3376, 2573, 2015, 1461,
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6867, 4994, 4202, 3377, 2800, 2164, 1718, 1243,
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5115, 3836, 3376, 2800, 2391, 1884, 1530, 1091,
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3798, 2869, 2573, 2164, 1884, 1495, 1212, 873,
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2942, 2229, 2015, 1718, 1530, 1212, 1001, 704,
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2076, 1619, 1461, 1243, 1091, 873, 704, 474
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},
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{
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23411,15604,13529,11601,10683, 8958, 7840, 6142,
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15604,11901,10718, 9108, 8290, 6961, 6023, 4487,
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13529,10718, 9961, 8527, 7945, 6689, 5742, 4333,
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11601, 9108, 8527, 7414, 7084, 5923, 5175, 3743,
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10683, 8290, 7945, 7084, 6771, 5754, 4793, 3504,
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8958, 6961, 6689, 5923, 5754, 4679, 3936, 2989,
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7840, 6023, 5742, 5175, 4793, 3936, 3522, 2558,
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6142, 4487, 4333, 3743, 3504, 2989, 2558, 1829
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}
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};
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/*The fraction of the squared magnitude of the residuals in each color channel
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relative to the total, scaled by 2**16, for each pixel format.
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These values were measured after motion-compensated prediction, before
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quantization, over a large set of test video encoded at all possible rates.
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TODO: These values are only from INTER frames; it should be re-measured for
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INTRA frames.*/
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static const ogg_uint16_t OC_PCD[4][3]={
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{59926, 3038, 2572},
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{55201, 5597, 4738},
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{55201, 5597, 4738},
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{47682, 9669, 8185}
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};
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/*Compute an "average" quantizer for each qi level.
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We do one for INTER and one for INTRA, since their behavior is very
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different, but average across chroma channels.
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The basic approach is to compute a harmonic average of the squared quantizer,
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weighted by the expected squared magnitude of the DCT coefficients.
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Under the (not quite true) assumption that DCT coefficients are
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Laplacian-distributed, this preserves the product Q*lambda, where
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lambda=sqrt(2/sigma**2) is the Laplacian distribution parameter (not to be
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confused with the lambda used in R-D optimization throughout most of the
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rest of the code).
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The value Q*lambda completely determines the entropy of the coefficients.*/
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void oc_enquant_qavg_init(ogg_int64_t _log_qavg[2][64],
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ogg_uint16_t *_dequant[64][3][2],int _pixel_fmt){
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int qi;
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int pli;
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int qti;
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int ci;
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for(qti=0;qti<2;qti++)for(qi=0;qi<64;qi++){
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ogg_int64_t q2;
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q2=0;
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for(pli=0;pli<3;pli++){
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ogg_uint32_t qp;
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qp=0;
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for(ci=0;ci<64;ci++){
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unsigned rq;
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unsigned qd;
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qd=_dequant[qi][pli][qti][OC_IZIG_ZAG[ci]];
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rq=(OC_RPSD[qti][ci]+(qd>>1))/qd;
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qp+=rq*(ogg_uint32_t)rq;
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}
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q2+=OC_PCD[_pixel_fmt][pli]*(ogg_int64_t)qp;
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}
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/*qavg=1.0/sqrt(q2).*/
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_log_qavg[qti][qi]=OC_Q57(48)-oc_blog64(q2)>>1;
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}
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}
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