📄 wvtpezw_tree_encode.cpp
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/****************************************************************************/
/* MPEG4 Visual Texture Coding (VTC) Mode Software */
/* */
/* This software was jointly developed by the following participants: */
/* */
/* Single-quant, multi-quant and flow control */
/* are provided by Sarnoff Corporation */
/* Iraj Sodagar (iraj@sarnoff.com) */
/* Hung-Ju Lee (hjlee@sarnoff.com) */
/* Paul Hatrack (hatrack@sarnoff.com) */
/* Shipeng Li (shipeng@sarnoff.com) */
/* Bing-Bing Chai (bchai@sarnoff.com) */
/* B.S. Srinivas (bsrinivas@sarnoff.com) */
/* */
/* Bi-level is provided by Texas Instruments */
/* Jie Liang (liang@ti.com) */
/* */
/* Shape Coding is provided by OKI Electric Industry Co., Ltd. */
/* Zhixiong Wu (sgo@hlabs.oki.co.jp) */
/* Yoshihiro Ueda (yueda@hlabs.oki.co.jp) */
/* Toshifumi Kanamaru (kanamaru@hlabs.oki.co.jp) */
/* */
/* OKI, Sharp, Sarnoff, TI and Microsoft contributed to bitstream */
/* exchange and bug fixing. */
/* */
/* */
/* In the course of development of the MPEG-4 standard, this software */
/* module is an implementation of a part of one or more MPEG-4 tools as */
/* specified by the MPEG-4 standard. */
/* */
/* The copyright of this software belongs to ISO/IEC. ISO/IEC gives use */
/* of the MPEG-4 standard free license to use this software module or */
/* modifications thereof for hardware or software products claiming */
/* conformance to the MPEG-4 standard. */
/* */
/* Those intending to use this software module in hardware or software */
/* products are advised that use may infringe existing patents. The */
/* original developers of this software module and their companies, the */
/* subsequent editors and their companies, and ISO/IEC have no liability */
/* and ISO/IEC have no liability for use of this software module or */
/* modification thereof in an implementation. */
/* */
/* Permission is granted to MPEG members to use, copy, modify, */
/* and distribute the software modules ( or portions thereof ) */
/* for standardization activity within ISO/IEC JTC1/SC29/WG11. */
/* */
/* Copyright 1995, 1996, 1997, 1998 ISO/IEC */
/****************************************************************************/
/****************************************************************************/
/* Texas Instruments Predictive Embedded Zerotree (PEZW) Image Codec */
/* Developed by Jie Liang (liang@ti.com) */
/* */
/* Copyright 1996, 1997, 1998 Texas Instruments */
/****************************************************************************/
/****************************************************************************
File name: wvtpezw_tree_encode.c
Author: Jie Liang (liang@ti.com)
Functions: Core functions for encoding the tree blocks of coeffs.
Revisions: v1.0 (10/04/98)
*****************************************************************************/
#include "wvtPEZW.hpp"
#include "PEZW_zerotree.hpp"
#include "wvtpezw_tree_codec.hpp"
#include "PEZW_functions.hpp"
/* encode a block of wavelet coefficients */
void PEZW_encode_block (WINT **coeffsBlk,int width, int height)
{
Int dc_hsize, dc_vsize;
Int i,j,k,band, hpos, vpos;
int pos;
int hpos_start, hpos_end;
int vpos_start, vpos_end;
Int lev, npix;
Int hstart, vstart,start, end;
Int x,y;
Int levels;
#ifdef DEBUG_FILE
Int NumTree=0;
#endif
levels = tree_depth;
dc_hsize = width>>levels;
dc_vsize = height>>levels;
/* encode the AC coefficients:
loop over all zerotrees */
for(i=0;i<dc_vsize;i++)
for (j=0;j<dc_hsize;j++)
for(band=0;band<3;band++)
{
/* copy the data into the wavelet tree */
if(band==0) { /* HL band */
hpos = j+dc_hsize;
vpos = i;
}
else if (band==1) { /* LH band */
hpos = j;
vpos = i+dc_vsize;
}
else{
hpos = j+dc_hsize;
vpos = i+dc_vsize;
}
y=vpos;x=hpos;
/* quantization and copy */
the_wvt_tree[0]=coeffsBlk[y][x];
for (lev=1;lev<levels;lev++)
{
npix=1<<(2*(lev-1));
pos = level_pos[lev];
hstart=hpos*(1<<(lev-1));
vstart=vpos*(1<<(lev-1));
start=level_pos[lev-1];
end=level_pos[lev];
for(k=start;k<end;k++)
{
hpos_start = (hstart+hloc_map[k])<<1;
hpos_end = hpos_start+2;
vpos_start = (vstart+vloc_map[k])<<1;
vpos_end = vpos_start+2;
for(y=vpos_start;y<vpos_end;y++)
for(x=hpos_start;x<hpos_end;x++){
/* quantization and copy */
the_wvt_tree[pos]=coeffsBlk[y][x];
pos++;
}
} /* end of k */
} /* end of for(lev) */
/* determin weighting */
for (lev=0;lev<levels;lev++)
snr_weight[lev] = 0;
/* initialization */
num_Sig=0;
prev_label[0]=ZTRZ;
for(k=1;k<len_tree_struct;k++)
prev_label[k]=DZ;
#ifdef DEBUG_FILE
NumTree++;
if(DEBUG_SYMBOL)
fprintf(fp_debug,"\n***NEW TREE %d***", NumTree);
#endif
/* encoder one wavelet tree. this function demonstrates that
the requirement for memory is very low for this entropy coder.
if combined with a localized wavelet transform, the total
memory requirement will be extremely low. */
PEZW_tree_encode (band,the_wvt_tree);
if(abs_wvt_tree[0]>MaxValue)
MaxValue=abs_wvt_tree[0];
if(wvt_tree_maxval[0]>MaxValue)
MaxValue=wvt_tree_maxval[0];
} /* end of band */
}
void PEZW_tree_encode (int band,WINT *wvt_tree)
{
int i,j,k,m;
int npix_block, npix;
int pix_pos, max_pos;
int maxval;
int bplane;
int scan_tree_done;
int context;
unsigned char label;
int num_ScanTree, next_numScanTree;
int temp1;
short *temp_ptr;
char signBit, Bit;
char IsStream=1;
unsigned char bpos;
char skip_flag;
char VAL_flag;
char treeBit, NoTree_flag;
//首先找出零树中系数的最大值
for (i=tree_depth-1;i>=1;i--){
npix_block = 1<<(2*(i-1));
pix_pos=level_pos[i];
max_pos=level_pos[i-1];
for(j=0;j<npix_block;j++){
maxval=0;
for(k=0;k<4;k++){
abs_wvt_tree[pix_pos]=ABS(wvt_tree[pix_pos]);
if(abs_wvt_tree[pix_pos]>maxval)
maxval=abs_wvt_tree[pix_pos];
if(i<tree_depth-1){
if(wvt_tree_maxval[pix_pos]>maxval)
maxval=wvt_tree_maxval[pix_pos];
}
pix_pos++;
}
wvt_tree_maxval[max_pos++]=maxval;
}
}
//最后一层
abs_wvt_tree[0]=ABS(wvt_tree[0]);
for(bplane=Max_Bitplane-1;bplane>=Min_Bitplane;bplane--){
#ifdef DEBUG_FILE
if(DEBUG_SYMBOL)
fprintf(fp_debug,"\n****bitplane: %d: ",bplane);
#endif
//判定编码的位平面
skip_flag=0;
for(i=0;i<tree_depth;i++){
bitplane[i] = bplane+snr_weight[i];
if(bitplane[i]>=Max_Bitplane)
skip_flag=1;
}
if(skip_flag)
continue; //跳过该位平面的编码
//发送细化比特数据
if(bplane<Max_Bitplane-1){
for(i=0;i<tree_depth;i++)
maskbit[i] = (1<<bitplane[i]);
for(i=0;i<num_Sig;i++){
m=sig_layer[i];
Bit=((abs_wvt_tree[sig_pos[i]]&maskbit[m])>0);
//用于细化比特数据编码的上下文
context = m*MAX_BITPLANE+bitplane[m];
Ac_encode_symbol(&Encoder[m][bitplane[m]],
&model_sub[context],Bit);
}
}
//建立零树并完成零树符号的编码，对于新的重要系数还要编码它的符号信息
//ScanTree:不是零树根后代的系数间隔
next_numScanTree=1; //ScanTree的数目
next_ScanTrees[0]=0;
next_ScanTrees[1]=1;
for(i=0;i<tree_depth;i++){
#ifdef DEBUG_FILE
if(DEBUG_SYMBOL)
fprintf(fp_debug,"\n++++tree_depth %d: ",i);
#endif
scan_tree_done=1;
num_ScanTree=next_numScanTree;
next_numScanTree=0;
temp_ptr=ScanTrees;
ScanTrees=next_ScanTrees;
next_ScanTrees=temp_ptr;
bpos=bitplane[i];
npix=1<<(2*i);
for(j=0;j<num_ScanTree;j++)
for(k=ScanTrees[2*j];k<ScanTrees[2*j+1];k++)
{
VAL_flag=0;
NoTree_flag=0;
//判定零树符号
if((prev_label[k]==IVAL)||(prev_label[k]==ZTRV)){
#ifdef DEBUG_FILE
if(DEBUG_SYMBOL){
fprintf(fp_debug,"SKIP%d ", prev_label[k]);
fflush(fp_debug);
}
#endif
if(i<tree_depth-1){
//为下一编码级建立扫描树
temp1=2*next_numScanTree;
next_ScanTrees[temp1]=level_pos[i+1]+4*(k-level_pos[i]);
next_ScanTrees[temp1+1]=next_ScanTrees[temp1]+4;
next_numScanTree++;
scan_tree_done=0;
}
continue;
}
else{
if(i==tree_depth-1){
NoTree_flag=1;
if(abs_wvt_tree[k]>>bpos){
label=IVAL;
VAL_flag=1;
sig_pos[num_Sig]=k;
sig_layer[num_Sig]=i;
num_Sig++;
}
else
label=IZER;
}
else if(wvt_tree_maxval[k]>>bpos)
{ //如果不是一颗零树
treeBit=0;
if(abs_wvt_tree[k]>>bpos){
label=IVAL;
VAL_flag=1;
if(prev_label[k]!=ZTRV){
sig_pos[num_Sig]=k;
sig_layer[num_Sig]=i;
num_Sig++;
}
else
VAL_flag=0;
}
else
label=IZER;
//为下一编码级建立扫描树
temp1=2*next_numScanTree;
next_ScanTrees[temp1]=level_pos[i+1]+4*(k-level_pos[i]);
next_ScanTrees[temp1+1]=next_ScanTrees[temp1]+4;
next_numScanTree++;
scan_tree_done=0;
}
else
{ //判定为零树根
treeBit=1;
if(abs_wvt_tree[k]>>bpos){
label=ZTRV;
VAL_flag=1;
sig_pos[num_Sig]=k;
sig_layer[num_Sig]=i;
num_Sig++;
}
else{
label=ZTRZ;
}
}
#ifdef DEBUG_FILE
if(DEBUG_SYMBOL){
fprintf(fp_debug,"%d ", label);
fflush(fp_debug);
}
#endif
//判定零树符号的上下文并完成编码
context=bpos*NumContexts*tree_depth+i*NumContexts+
prev_label[k]*NumBands+band;
Ac_encode_symbol(&Encoder[i][bpos],&context_model[context],label);
//编码重要系数的符号位信息
if(VAL_flag){
signBit = (wvt_tree[k]>0);
#ifdef DEBUG_FILE
if(DEBUG_SYMBOL){
if(signBit==1)
fprintf(fp_debug,"%d+ ",signBit);
else
fprintf(fp_debug,"%d- ",signBit);
fflush(fp_debug);
}
#endif
//用于符号信息编码的上下文
context = i*MAX_BITPLANE+bpos;
Ac_encode_symbol(&Encoder[i][bpos],&model_sign[context],signBit);
}
//更新上下文标记
prev_label[k]=label;
}
}
//如果没有子带存在非零的后代
if(scan_tree_done)
break;
}
}
return;
}
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