www.pudn.com > wavecode.rar > coder_o2.c

 
/********* 
 
Order2 : o2 on MSB's 
 
S+P (512) Lossless : 
 
			Lena	Zelda	Kuha	Checa(256) 
Order1 	:	4.250	3.948	3.534	3.406 
Order1+1:	4.207	3.911	3.517	3.310 
Order1sb:	4.216	3.920	3.510	3.305 
order2	:	4.222	3.928	3.511	3.308 
 
We're uniformly beaten by the order1 coders.  This is 
strong evidence that we can do no better than order1. (sigh) 
 
	-> this is not quite right.  height data (golf courses) 
		and digitial images (circles & crosses .256) are 
		better under order2 
 
------ 
 
todos : 
 
	1. different order0 for each bit-position of residuals, ? 
		(since the lowest bit-pos will be very random, 
		highers should be more zero-skewed) 
 
	2. different order1 contexts?  average of neighbor & parent? 
 
**********/ 
 
#include  
#include  
#include  
#include  
#include  
 
extern int tune_param; 
 
// #define SMEAR_PARENT // hurts 0.03 !? 
 
#define ORDER2_TOTMAX		6000 
#define ORDER2_INC			30 
#define ORDER2_ESCINC		30 
 
#define ORDER1_TOTMAX		10000 
#define ORDER1_INC			30 
 
#define MSB_RAWS			1 
#define MSB_ALPHABET		(18 + MSB_RAWS)	/** # of bits **/ 
 
#define O2_MAX_PREV			3 
#define O2_MAX_PARENT		5 
#define O2_CONTEXTS 		(1 + O2_MAX_PREV + (O2_MAX_PREV+1)*O2_MAX_PARENT) 
#define O1_MAX_PARENT		2	/** zero seems optimal, which makes this into order-1, not order-2 ! **/ 
#define O1_CONTEXTS			(O1_MAX_PARENT+1) 
 
#define ORDER0_TOTMAX		16000	/** totally irrelevant **/ 
#define ORDER0_ALPHABET		2		/** binary **/ 
#define ORDER0_INC			10 
 
#include "coder.h" 
 
void coderO2_encodeBand(coder *me,int *band,int w,int h,int fullw,int *parent); 
void coderO2_decodeBand(coder *me,int *band,int w,int h,int fullw,int *parent); 
 
typedef struct { 
	scontext *o0; 
	scontext *sign_sc[3]; 
	scontext **o1,**o2; 
	arithInfo *ari; 
} myInfo; 
 
void coderO2_init(coder *c) 
{ 
myInfo *d; 
int i; 
 
	if ( (d = new(myInfo)) == NULL ) 
		errexit("ozero init failed"); 
 
	c->data = d; 
	d->ari = c->arith; 
 
	if ( (d->o0 = scontextCreate(c->arith,ORDER0_ALPHABET,0, 
			ORDER0_TOTMAX,ORDER0_INC,true)) == NULL ) 
		errexit("ozero init failed"); 
 
	for(i=0;i<3;i++) { 
		if ( (d->sign_sc[i] = scontextCreate(c->arith,2,0,1000,10,true)) == NULL ) 
			errexit("sign ozero init failed"); 
	} 
 
	if ( (d->o1 = newarray(void *,O1_CONTEXTS)) == NULL ) 
		errexit("Order1_Init failed!"); 
 
	for(i=0;io1[i] = scontextCreate(c->arith,MSB_ALPHABET,0, 
				ORDER1_TOTMAX,ORDER1_INC,true)) == NULL ) 
			errexit("context o1 creation failed!"); 
	} 
 
	if ( (d->o2 = newarray(void *,O2_CONTEXTS)) == NULL ) 
		errexit("Order2_Init failed!"); 
 
	for(i=0;io2[i] = scontextCreate(c->arith,MSB_ALPHABET, 
				ORDER2_ESCINC,ORDER2_TOTMAX,ORDER2_INC,false)) == NULL ) 
			errexit("context o2 creation failed!"); 
	} 
} 
 
void coderO2_free(coder *c) 
{ 
	if ( c->data ) { 
		myInfo *d; int i; 
 
		d = c->data; 
		if ( d->o0 ) scontextFree(d->o0); 
		for(i=0;i<3;i++) { 
			if ( d->sign_sc[i] ) scontextFree(d->sign_sc[i]); 
		} 
		if ( d->o1 ) { 
			for(i=0;io1[i] ) scontextFree(d->o1[i]); 
			} 
		} 
		if ( d->o2 ) { 
			for(i=0;io2[i] ) scontextFree(d->o2[i]); 
			} 
		} 
		free(d); 
		c->data = NULL; 
	} 
} 
 
coder coderO2 = { 
		"order 2", 
		coderO2_init, 
		coderO2_free, 
		coderO2_encodeBand, 
		coderO2_decodeBand 
	}; 
 
static void mcontext(int *cur_ptr,int *parent_ptr,int x,int y,int width,int height,int fullw, 
	int *cntx1_ptr,int *cntx2_ptr,int *sign_ptr) 
{ 
int neighbors,parent; 
 
	/** cur_ptr[0] is about to be coded **/ 
 
	if ( x==0 ) { 
		if ( y == 0 ) { 
			neighbors = 0; 
		} else { 
			neighbors = (cur_ptr[-fullw] + cur_ptr[-fullw+1]) >> 1; 
		} 
	} else if ( y == 0 ) { 
		neighbors = cur_ptr[-1]; 
	} else if ( x == (width-1) ) { 
		neighbors = (cur_ptr[-1] + cur_ptr[-fullw] + cur_ptr[-fullw] + cur_ptr[-fullw-1]) >> 2; 
	} else { 
		neighbors = (cur_ptr[-1] + cur_ptr[-fullw] + cur_ptr[-fullw+1] + cur_ptr[-fullw-1]) >> 2; 
	} 
 
if ( neighbors == 0 ) *sign_ptr = 2; 
else if ( isneg(neighbors) ) *sign_ptr = 1; 
else *sign_ptr = 0; 
 
#ifdef SMEAR_PARENT 
if ( x >= 2 && x < (width-2) ) { 
	parent = abs(parent_ptr[0] + parent_ptr[0] + parent_ptr[-1] + parent_ptr[1] + 2); 
	parent >>= 2; 
} else { 
	parent = abs(*parent_ptr); 
} 
#else 
	parent = abs(*parent_ptr); 
#endif // SMEAR_PARENT 
 
*cntx1_ptr = min(O1_MAX_PARENT,parent); 
 
neighbors = abs(neighbors); 
parent = intlog2(parent+1); 
neighbors = intlog2(neighbors); 
 
*cntx2_ptr = min(O2_MAX_PREV,neighbors) + (O2_MAX_PREV+1)*(min(O2_MAX_PARENT,parent)); 
 
} 
 
static void encode_val(myInfo *mi,int sym,int cntx1,int cntx2) 
{ 
	if ( sym < MSB_RAWS ) { 
		if ( ! scontextEncode(mi->o2[cntx2],sym) ) 
			scontextEncode(mi->o1[cntx1],sym); 
	} else { 
		int bits,msb; 
		sym -= (MSB_RAWS-1); 	/** can't use zero **/ 
		bits = intlog2(sym); 
		msb = (1<o2[cntx2],bits) ) 
			scontextEncode(mi->o1[cntx1],bits); 
 
		/** sym < msb now **/ 
		msb>>=1; 
		for(;msb>=1;msb>>=1) { 
			scontextEncode(mi->o0,(sym&msb)?1:0); 
		} 
	} 
} 
 
static int decode_val(myInfo *mi,int cntx1,int cntx2) 
{ 
int bits; 
 
if ( (bits = scontextDecode(mi->o2[cntx2])) == - 1) { 
	bits = scontextDecode(mi->o1[cntx1]); 
	scontextAdd(mi->o2[cntx2],bits); 
} 
 
	if ( bits < MSB_RAWS ) { 
		return bits; 
	} else { 
		int msb,sym,top; 
		bits -= MSB_RAWS; 
		msb = 1<>1;top>=1;top>>=1) { 
			if ( scontextDecode(mi->o0) ) sym += top; 
		} 
		sym += msb + MSB_RAWS - 1; 
		return sym; 
	} 
} 
 
void coderO2_encodeBand(coder *me,int *band,int width,int height,int fullw,int *parent) 
{ 
int x,y,val,cntx1,cntx2,sign,sign_cntx; 
int *dp,*pp,*dpp,*ppp; 
myInfo *mi = ((myInfo *)me->data); 
scontext **sign_sc = ((myInfo *)me->data)->sign_sc; 
 
	dp = band; 
	pp = parent; 
	for(y=0;ydata); 
scontext **sign_sc = ((myInfo *)me->data)->sign_sc; 
 
	dp = band; 
	pp = parent; 
	for(y=0;y