vpx/vp8/common/idctllm.c
Yaowu Xu 152ce6b2b9 fixed the wrong rounding in inverse haar transform
Given the current forward haar transform:
 f0 = I0 + I1 + I2 + I3
 f1 = I0 + I1 - I2 - I3
 f2 = I0 - I1 + I2 - I3
 f3 = I0 - I1 - I2 + I3
the output of the inverse haar prior rounding:
 i0 = f0 + f1 + f2 + f3 = I0 * 4;
 i1 = f0 + f1 - f2 - f3 = I1 * 4;
 i2 = f0 - f1 + f2 - f3 = I2 * 4;
 i3 = f0 - f1 - f2 + f3 = I3 * 4;
As all the numbers are 4 multiples, simply >>2 always produces prefect
results in term of forward-inverse transform round trip error.

Change-Id: Id6658b00ea819ee61cfeef8c5985d4cd3e77f44e
2011-10-14 09:33:54 -07:00

534 lines
12 KiB
C

/*
* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
/****************************************************************************
* Notes:
*
* This implementation makes use of 16 bit fixed point verio of two multiply
* constants:
* 1. sqrt(2) * cos (pi/8)
* 2. sqrt(2) * sin (pi/8)
* Becuase the first constant is bigger than 1, to maintain the same 16 bit
* fixed point precision as the second one, we use a trick of
* x * a = x + x*(a-1)
* so
* x * sqrt(2) * cos (pi/8) = x + x * (sqrt(2) *cos(pi/8)-1).
**************************************************************************/
#include "vpx_ports/config.h"
#include <math.h>
static const int cospi8sqrt2minus1 = 20091;
static const int sinpi8sqrt2 = 35468;
static const int rounding = 0;
void vp8_short_idct4x4llm_c(short *input, short *output, int pitch)
{
int i;
int a1, b1, c1, d1;
short *ip = input;
short *op = output;
int temp1, temp2;
int shortpitch = pitch >> 1;
for (i = 0; i < 4; i++)
{
a1 = ip[0] + ip[8];
b1 = ip[0] - ip[8];
temp1 = (ip[4] * sinpi8sqrt2 + rounding) >> 16;
temp2 = ip[12] + ((ip[12] * cospi8sqrt2minus1 + rounding) >> 16);
c1 = temp1 - temp2;
temp1 = ip[4] + ((ip[4] * cospi8sqrt2minus1 + rounding) >> 16);
temp2 = (ip[12] * sinpi8sqrt2 + rounding) >> 16;
d1 = temp1 + temp2;
op[shortpitch*0] = a1 + d1;
op[shortpitch*3] = a1 - d1;
op[shortpitch*1] = b1 + c1;
op[shortpitch*2] = b1 - c1;
ip++;
op++;
}
ip = output;
op = output;
for (i = 0; i < 4; i++)
{
a1 = ip[0] + ip[2];
b1 = ip[0] - ip[2];
temp1 = (ip[1] * sinpi8sqrt2 + rounding) >> 16;
temp2 = ip[3] + ((ip[3] * cospi8sqrt2minus1 + rounding) >> 16);
c1 = temp1 - temp2;
temp1 = ip[1] + ((ip[1] * cospi8sqrt2minus1 + rounding) >> 16);
temp2 = (ip[3] * sinpi8sqrt2 + rounding) >> 16;
d1 = temp1 + temp2;
#if !CONFIG_EXTEND_QRANGE
op[0] = (a1 + d1 + 4) >> 3;
op[3] = (a1 - d1 + 4) >> 3;
op[1] = (b1 + c1 + 4) >> 3;
op[2] = (b1 - c1 + 4) >> 3;
#else
op[0] = (a1 + d1 + 16) >> 5;
op[3] = (a1 - d1 + 16) >> 5;
op[1] = (b1 + c1 + 16) >> 5;
op[2] = (b1 - c1 + 16) >> 5;
#endif
ip += shortpitch;
op += shortpitch;
}
}
void vp8_short_idct4x4llm_1_c(short *input, short *output, int pitch)
{
int i;
int a1;
short *op = output;
int shortpitch = pitch >> 1;
#if !CONFIG_EXTEND_QRANGE
a1 = ((input[0] + 4) >> 3);
#else
a1 = ((input[0] + 16) >> 5);
#endif
for (i = 0; i < 4; i++)
{
op[0] = a1;
op[1] = a1;
op[2] = a1;
op[3] = a1;
op += shortpitch;
}
}
void vp8_dc_only_idct_add_c(short input_dc, unsigned char *pred_ptr, unsigned char *dst_ptr, int pitch, int stride)
{
#if !CONFIG_EXTEND_QRANGE
int a1 = ((input_dc + 4) >> 3);
#else
int a1 = ((input_dc + 16) >> 5);
#endif
int r, c;
for (r = 0; r < 4; r++)
{
for (c = 0; c < 4; c++)
{
int a = a1 + pred_ptr[c] ;
if (a < 0)
a = 0;
if (a > 255)
a = 255;
dst_ptr[c] = (unsigned char) a ;
}
dst_ptr += stride;
pred_ptr += pitch;
}
}
void vp8_short_inv_walsh4x4_c(short *input, short *output)
{
int i;
int a1, b1, c1, d1;
int a2, b2, c2, d2;
short *ip = input;
short *op = output;
for (i = 0; i < 4; i++)
{
a1 = ip[0] + ip[12];
b1 = ip[4] + ip[8];
c1 = ip[4] - ip[8];
d1 = ip[0] - ip[12];
op[0] = a1 + b1;
op[4] = c1 + d1;
op[8] = a1 - b1;
op[12] = d1 - c1;
ip++;
op++;
}
ip = output;
op = output;
for (i = 0; i < 4; i++)
{
a1 = ip[0] + ip[3];
b1 = ip[1] + ip[2];
c1 = ip[1] - ip[2];
d1 = ip[0] - ip[3];
a2 = a1 + b1;
b2 = c1 + d1;
c2 = a1 - b1;
d2 = d1 - c1;
#if !CONFIG_EXTEND_QRANGE
op[0] = (a2 + 3) >> 3;
op[1] = (b2 + 3) >> 3;
op[2] = (c2 + 3) >> 3;
op[3] = (d2 + 3) >> 3;
#else
op[0] = (a2 + 1) >> 2;
op[1] = (b2 + 1) >> 2;
op[2] = (c2 + 1) >> 2;
op[3] = (d2 + 1) >> 2;
#endif
ip += 4;
op += 4;
}
}
void vp8_short_inv_walsh4x4_1_c(short *input, short *output)
{
int i;
int a1;
short *op = output;
#if !CONFIG_EXTEND_QRANGE
a1 = (input[0] + 3 )>> 3;
#else
a1 = (input[0] + 1 )>> 2;
#endif
for (i = 0; i < 4; i++)
{
op[0] = a1;
op[1] = a1;
op[2] = a1;
op[3] = a1;
op += 4;
}
}
#if CONFIG_T8X8
#define FAST_IDCT_8X8
void vp8_short_idct8x8_1_c(short *input, short *output, int pitch)
{
int i, b;
int a1;
short *op = output;
short *orig_op = output;
int shortpitch = pitch >> 1;
a1 = ((input[0] + 4) >> 3);
for (b = 0; b < 4; b++)
{
for (i = 0; i < 4; i++)
{
op[0] = a1;
op[1] = a1;
op[2] = a1;
op[3] = a1;
op += shortpitch;
}
op = orig_op + (b+1)%2*4 +(b+1)/2*4*shortpitch;
}
}
void vp8_dc_only_idct_add_8x8_c(short input_dc, unsigned char *pred_ptr, unsigned char *dst_ptr, int pitch, int stride)
{
int a1 = ((input_dc + 4) >> 3);
int r, c, b;
unsigned char *orig_pred = pred_ptr;
unsigned char *orig_dst = dst_ptr;
for (b = 0; b < 4; b++)
{
for (r = 0; r < 4; r++)
{
for (c = 0; c < 4; c++)
{
int a = a1 + pred_ptr[c] ;
if (a < 0)
a = 0;
if (a > 255)
a = 255;
dst_ptr[c] = (unsigned char) a ;
}
dst_ptr += stride;
pred_ptr += pitch;
}
dst_ptr = orig_dst + (b+1)%2*4 + (b+1)/2*4*stride;
pred_ptr = orig_pred + (b+1)%2*4 + (b+1)/2*4*pitch;
}
}
#ifdef FAST_IDCT_8X8
#define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */
#define W2 2676 /* 2048*sqrt(2)*cos(2*pi/16) */
#define W3 2408 /* 2048*sqrt(2)*cos(3*pi/16) */
#define W5 1609 /* 2048*sqrt(2)*cos(5*pi/16) */
#define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */
#define W7 565 /* 2048*sqrt(2)*cos(7*pi/16) */
/* row (horizontal) IDCT
*
* 7 pi 1 dst[k] = sum c[l] * src[l] * cos( -- *
* ( k + - ) * l ) l=0 8 2
*
* where: c[0] = 128 c[1..7] = 128*sqrt(2) */
static void idctrow (int *blk)
{
int x0, x1, x2, x3, x4, x5, x6, x7, x8;
/* shortcut */
if (!((x1 = blk[4] << 11) | (x2 = blk[6]) | (x3 = blk[2]) |
(x4 = blk[1]) | (x5 = blk[7]) | (x6 = blk[5]) | (x7 = blk[3])))
{
blk[0] = blk[1] = blk[2] = blk[3] = blk[4] = blk[5] = blk[6] = blk[7] = blk[0] << 3;
return;
}
x0 = (blk[0] << 11) + 128; /* for proper rounding in the fourth stage */
/* first stage */
x8 = W7 * (x4 + x5);
x4 = x8 + (W1 - W7) * x4;
x5 = x8 - (W1 + W7) * x5;
x8 = W3 * (x6 + x7);
x6 = x8 - (W3 - W5) * x6;
x7 = x8 - (W3 + W5) * x7;
/* second stage */
x8 = x0 + x1;
x0 -= x1;
x1 = W6 * (x3 + x2);
x2 = x1 - (W2 + W6) * x2;
x3 = x1 + (W2 - W6) * x3;
x1 = x4 + x6;
x4 -= x6;
x6 = x5 + x7;
x5 -= x7;
/* third stage */
x7 = x8 + x3;
x8 -= x3;
x3 = x0 + x2;
x0 -= x2;
x2 = (181 * (x4 + x5) + 128) >> 8;
x4 = (181 * (x4 - x5) + 128) >> 8;
/* fourth stage */
blk[0] = (x7 + x1) >> 8;
blk[1] = (x3 + x2) >> 8;
blk[2] = (x0 + x4) >> 8;
blk[3] = (x8 + x6) >> 8;
blk[4] = (x8 - x6) >> 8;
blk[5] = (x0 - x4) >> 8;
blk[6] = (x3 - x2) >> 8;
blk[7] = (x7 - x1) >> 8;
}
/* column (vertical) IDCT
*
* 7 pi 1 dst[8*k] = sum c[l] * src[8*l] *
* cos( -- * ( k + - ) * l ) l=0 8 2
*
* where: c[0] = 1/1024 c[1..7] = (1/1024)*sqrt(2) */
static void idctcol (int *blk)
{
int x0, x1, x2, x3, x4, x5, x6, x7, x8;
/* shortcut */
if (!((x1 = (blk[8 * 4] << 8)) | (x2 = blk[8 * 6]) | (x3 = blk[8 * 2]) |
(x4 = blk[8 * 1]) | (x5 = blk[8 * 7]) | (x6 = blk[8 * 5]) | (x7 = blk[8 * 3])))
{
blk[8 * 0] = blk[8 * 1] = blk[8 * 2] = blk[8 * 3] = blk[8 * 4] = blk[8 * 5] = blk[8 * 6] = blk[8 * 7] =
((blk[8 * 0] + 32) >> 6);
return;
}
x0 = (blk[8 * 0] << 8) + 8192;
/* first stage */
x8 = W7 * (x4 + x5) + 4;
x4 = (x8 + (W1 - W7) * x4) >> 3;
x5 = (x8 - (W1 + W7) * x5) >> 3;
x8 = W3 * (x6 + x7) + 4;
x6 = (x8 - (W3 - W5) * x6) >> 3;
x7 = (x8 - (W3 + W5) * x7) >> 3;
/* second stage */
x8 = x0 + x1;
x0 -= x1;
x1 = W6 * (x3 + x2) + 4;
x2 = (x1 - (W2 + W6) * x2) >> 3;
x3 = (x1 + (W2 - W6) * x3) >> 3;
x1 = x4 + x6;
x4 -= x6;
x6 = x5 + x7;
x5 -= x7;
/* third stage */
x7 = x8 + x3;
x8 -= x3;
x3 = x0 + x2;
x0 -= x2;
x2 = (181 * (x4 + x5) + 128) >> 8;
x4 = (181 * (x4 - x5) + 128) >> 8;
/* fourth stage */
blk[8 * 0] = (x7 + x1) >> 14;
blk[8 * 1] = (x3 + x2) >> 14;
blk[8 * 2] = (x0 + x4) >> 14;
blk[8 * 3] = (x8 + x6) >> 14;
blk[8 * 4] = (x8 - x6) >> 14;
blk[8 * 5] = (x0 - x4) >> 14;
blk[8 * 6] = (x3 - x2) >> 14;
blk[8 * 7] = (x7 - x1) >> 14;
}
#define TX_DIM 8
void vp8_short_idct8x8_c(short *coefs, short *block, int pitch)
// an approximate 8x8 dct implementation, but not used
{
int X[TX_DIM*TX_DIM];
int i,j;
int shortpitch = pitch >> 1;
for (i = 0; i < TX_DIM; i++)
{
for (j = 0; j < TX_DIM; j++)
{
X[i * TX_DIM + j] = (int)coefs[i * TX_DIM + j];
}
}
for (i = 0; i < 8; i++)
idctrow (X + 8 * i);
for (i = 0; i < 8; i++)
idctcol (X + i);
for (i = 0; i < TX_DIM; i++)
{
for (j = 0; j < TX_DIM; j++)
{
block[i*shortpitch+j] = X[i * TX_DIM + j]>>1;
}
}
}
#else
/* This is really for testing */
void vp8_short_idct8x8_c(short *input, short *output, int pitch)
{
int X[8][8];
double C[8][8]={{0.0}}, Ct[8][8]={{0.0}}, temp[8][8]={{0.0}};
int i,j,k;
double temp1=0.0;
double pi = atan( 1.0 ) * 4.0;
//static int count=0;
int shortpitch = pitch >> 1;
for (i = 0; i < 8; i++)
{
for (j = 0; j < 8; j++)
{
X[i][j] = input[i * 8 + j];
}
}
// TODO: DCT matrix should be calculated once for all
for ( j = 0 ; j < 8 ; j++ ) {
C[ 0 ][ j ] = 1.0 / sqrt( (double) 8 );
Ct[ j ][ 0 ] = C[ 0 ][ j ];
}
for ( i = 1 ; i < 8 ; i++ ) {
for ( j = 0 ; j < 8 ; j++ ) {
C[ i ][ j ] = sqrt( 2.0 / 8 ) *
cos( pi * ( 2 * j + 1 ) * i / ( 2.0 * 8 ) );
Ct[ j ][ i ] = C[ i ][ j ];
}
}
/* MatrixMultiply( temp, input, C ); */
for ( i = 0 ; i < 8 ; i++ ) {
for ( j = 0 ; j < 8 ; j++ ) {
temp[ i ][ j ] = 0.0;
for ( k = 0 ; k < 8 ; k++ )
temp[ i ][ j ] += X[ i ][ k ] * C[ k ][ j ];
}
}
/* MatrixMultiply( output, Ct, temp ); */
for ( i = 0 ; i < 8 ; i++ ) {
for ( j = 0 ; j < 8 ; j++ ) {
temp1 = 0.0;
for ( k = 0 ; k < 8 ; k++ )
temp1 += Ct[ i ][ k ] * temp[ k ][ j ];
X[ i ][ j ] = floor( temp1/ 2.0 + 0.5);
}
}
for (i = 0; i < 8; i++)
{
for (j = 0; j < 8; j++)
{
output[i*shortpitch+j] = X[i][j];
}
}
}
#endif
void vp8_short_ihaar2x2_c(short *input, short *output, int pitch)
{
int i, x;
short *ip = input; //0,1, 4, 8
short *op = output;
for (i = 0; i < 16; i++)
{
op[i] = 0;
}
op[0] = (ip[0] + ip[1] + ip[4] + ip[8])>>2;
op[1] = (ip[0] - ip[1] + ip[4] - ip[8])>>2;
op[4] = (ip[0] + ip[1] - ip[4] - ip[8])>>2;
op[8] = (ip[0] - ip[1] - ip[4] + ip[8])>>2;
}
void vp8_short_ihaar2x2_1_c(short *input, short *output, int pitch)
{
int a1;
short *ip = input;
short *op = output;
a1 = ip[0]>> 2;
op[0] = a1;
op[2] = a1;
op[8] = a1;
op[10] = a1;
}
#endif