7968d29fed
This commit changed the forward and the inverse 4x4 Walsh Hadamard transform to a new pair, where the inverse transform can pefectly reconstuct the input to forward transform. It also does so without changing the input and output value range. Even more, it does not change the complexity of the transforms. While it was not expected to improve the results of our current test, it does improve std-hd set by 0.2% on all metrics. No change on derf. Change-Id: Ie4f23ddd3a0f3c5fbe97fb58399f860031f99337
406 lines
9.8 KiB
C
406 lines
9.8 KiB
C
/*
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* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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/****************************************************************************
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* Notes:
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*
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* This implementation makes use of 16 bit fixed point verio of two multiply
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* constants:
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* 1. sqrt(2) * cos (pi/8)
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* 2. sqrt(2) * sin (pi/8)
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* Becuase the first constant is bigger than 1, to maintain the same 16 bit
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* fixed point precision as the second one, we use a trick of
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* x * a = x + x*(a-1)
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* so
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* x * sqrt(2) * cos (pi/8) = x + x * (sqrt(2) *cos(pi/8)-1).
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**************************************************************************/
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#include "vpx_ports/config.h"
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#include <math.h>
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static const int cospi8sqrt2minus1 = 20091;
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static const int sinpi8sqrt2 = 35468;
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static const int rounding = 0;
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void vp8_short_idct4x4llm_c(short *input, short *output, int pitch)
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{
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int i;
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int a1, b1, c1, d1;
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short *ip = input;
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short *op = output;
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int temp1, temp2;
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int shortpitch = pitch >> 1;
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for (i = 0; i < 4; i++)
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{
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a1 = ip[0] + ip[8];
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b1 = ip[0] - ip[8];
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temp1 = (ip[4] * sinpi8sqrt2 + rounding) >> 16;
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temp2 = ip[12] + ((ip[12] * cospi8sqrt2minus1 + rounding) >> 16);
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c1 = temp1 - temp2;
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temp1 = ip[4] + ((ip[4] * cospi8sqrt2minus1 + rounding) >> 16);
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temp2 = (ip[12] * sinpi8sqrt2 + rounding) >> 16;
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d1 = temp1 + temp2;
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op[shortpitch*0] = a1 + d1;
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op[shortpitch*3] = a1 - d1;
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op[shortpitch*1] = b1 + c1;
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op[shortpitch*2] = b1 - c1;
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ip++;
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op++;
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}
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ip = output;
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op = output;
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for (i = 0; i < 4; i++)
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{
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a1 = ip[0] + ip[2];
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b1 = ip[0] - ip[2];
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temp1 = (ip[1] * sinpi8sqrt2 + rounding) >> 16;
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temp2 = ip[3] + ((ip[3] * cospi8sqrt2minus1 + rounding) >> 16);
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c1 = temp1 - temp2;
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temp1 = ip[1] + ((ip[1] * cospi8sqrt2minus1 + rounding) >> 16);
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temp2 = (ip[3] * sinpi8sqrt2 + rounding) >> 16;
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d1 = temp1 + temp2;
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op[0] = (a1 + d1 + 16) >> 5;
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op[3] = (a1 - d1 + 16) >> 5;
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op[1] = (b1 + c1 + 16) >> 5;
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op[2] = (b1 - c1 + 16) >> 5;
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ip += shortpitch;
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op += shortpitch;
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}
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}
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void vp8_short_idct4x4llm_1_c(short *input, short *output, int pitch)
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{
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int i;
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int a1;
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short *op = output;
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int shortpitch = pitch >> 1;
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a1 = ((input[0] + 16) >> 5);
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for (i = 0; i < 4; i++)
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{
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op[0] = a1;
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op[1] = a1;
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op[2] = a1;
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op[3] = a1;
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op += shortpitch;
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}
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}
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void vp8_dc_only_idct_add_c(short input_dc, unsigned char *pred_ptr, unsigned char *dst_ptr, int pitch, int stride)
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{
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int a1 = ((input_dc + 16) >> 5);
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int r, c;
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for (r = 0; r < 4; r++)
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{
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for (c = 0; c < 4; c++)
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{
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int a = a1 + pred_ptr[c] ;
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if (a < 0)
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a = 0;
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if (a > 255)
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a = 255;
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dst_ptr[c] = (unsigned char) a ;
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}
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dst_ptr += stride;
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pred_ptr += pitch;
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}
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}
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void vp8_short_inv_walsh4x4_c(short *input, short *output)
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{
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int i;
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int a1, b1, c1, d1;
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short *ip = input;
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short *op = output;
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for (i = 0; i < 4; i++)
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{
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a1 = ((ip[0] + ip[3]));
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b1 = ((ip[1] + ip[2]));
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c1 = ((ip[1] - ip[2]));
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d1 = ((ip[0] - ip[3]));
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op[0] = (a1 + b1 + 1)>>1;
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op[1] = (c1 + d1)>>1;
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op[2] = (a1 - b1)>>1;
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op[3] = (d1 - c1)>>1;
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ip += 4;
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op += 4;
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}
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ip = output;
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op = output;
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for (i = 0; i < 4; i++)
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{
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a1 = ip[0] + ip[12];
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b1 = ip[4] + ip[8];
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c1 = ip[4] - ip[8];
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d1 = ip[0] - ip[12];
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op[0] = (a1 + b1 + 1)>>1;
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op[4] = (c1 + d1)>>1;
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op[8] = (a1 - b1)>>1;
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op[12]= (d1 - c1)>>1;
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ip++;
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op++;
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}
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}
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void vp8_short_inv_walsh4x4_1_c(short *in, short *out)
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{
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int i;
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short tmp[4];
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short *ip = in;
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short *op = tmp;
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op[0] =(ip[0]+ 1)>>1;
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op[1] = op[2] = op[3] = (ip[0]>>1);
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ip = tmp;
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op = out;
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for(i = 0; i<4; i++)
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{
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op[0] =(ip[0]+ 1)>>1;
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op[4] = op[8] = op[12] = (ip[0]>>1);
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ip ++;
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op ++;
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}
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}
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void vp8_dc_only_idct_add_8x8_c(short input_dc,
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unsigned char *pred_ptr,
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unsigned char *dst_ptr,
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int pitch, int stride)
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{
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int a1 = ((input_dc + 16) >> 5);
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int r, c, b;
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unsigned char *orig_pred = pred_ptr;
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unsigned char *orig_dst = dst_ptr;
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for (b = 0; b < 4; b++)
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{
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for (r = 0; r < 4; r++)
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{
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for (c = 0; c < 4; c++)
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{
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int a = a1 + pred_ptr[c] ;
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if (a < 0)
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a = 0;
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if (a > 255)
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a = 255;
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dst_ptr[c] = (unsigned char) a ;
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}
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dst_ptr += stride;
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pred_ptr += pitch;
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}
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dst_ptr = orig_dst + (b+1)%2*4 + (b+1)/2*4*stride;
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pred_ptr = orig_pred + (b+1)%2*4 + (b+1)/2*4*pitch;
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}
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}
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#define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */
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#define W2 2676 /* 2048*sqrt(2)*cos(2*pi/16) */
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#define W3 2408 /* 2048*sqrt(2)*cos(3*pi/16) */
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#define W5 1609 /* 2048*sqrt(2)*cos(5*pi/16) */
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#define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */
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#define W7 565 /* 2048*sqrt(2)*cos(7*pi/16) */
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/* row (horizontal) IDCT
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*
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* 7 pi 1 dst[k] = sum c[l] * src[l] * cos( -- *
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* ( k + - ) * l ) l=0 8 2
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*
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* where: c[0] = 128 c[1..7] = 128*sqrt(2) */
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static void idctrow (int *blk)
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{
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int x0, x1, x2, x3, x4, x5, x6, x7, x8;
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/* shortcut */
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if (!((x1 = blk[4] << 11) | (x2 = blk[6]) | (x3 = blk[2]) |
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(x4 = blk[1]) | (x5 = blk[7]) | (x6 = blk[5]) | (x7 = blk[3])))
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{
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blk[0] = blk[1] = blk[2] = blk[3] = blk[4]
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= blk[5] = blk[6] = blk[7] = blk[0] << 3;
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return;
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}
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x0 = (blk[0] << 11) + 128; /* for proper rounding in the fourth stage */
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/* first stage */
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x8 = W7 * (x4 + x5);
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x4 = x8 + (W1 - W7) * x4;
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x5 = x8 - (W1 + W7) * x5;
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x8 = W3 * (x6 + x7);
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x6 = x8 - (W3 - W5) * x6;
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x7 = x8 - (W3 + W5) * x7;
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/* second stage */
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x8 = x0 + x1;
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x0 -= x1;
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x1 = W6 * (x3 + x2);
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x2 = x1 - (W2 + W6) * x2;
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x3 = x1 + (W2 - W6) * x3;
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x1 = x4 + x6;
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x4 -= x6;
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x6 = x5 + x7;
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x5 -= x7;
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/* third stage */
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x7 = x8 + x3;
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x8 -= x3;
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x3 = x0 + x2;
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x0 -= x2;
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x2 = (181 * (x4 + x5) + 128) >> 8;
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x4 = (181 * (x4 - x5) + 128) >> 8;
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/* fourth stage */
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blk[0] = (x7 + x1) >> 8;
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blk[1] = (x3 + x2) >> 8;
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blk[2] = (x0 + x4) >> 8;
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blk[3] = (x8 + x6) >> 8;
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blk[4] = (x8 - x6) >> 8;
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blk[5] = (x0 - x4) >> 8;
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blk[6] = (x3 - x2) >> 8;
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blk[7] = (x7 - x1) >> 8;
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}
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/* column (vertical) IDCT
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*
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* 7 pi 1 dst[8*k] = sum c[l] * src[8*l] *
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* cos( -- * ( k + - ) * l ) l=0 8 2
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*
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* where: c[0] = 1/1024 c[1..7] = (1/1024)*sqrt(2) */
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static void idctcol (int *blk)
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{
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int x0, x1, x2, x3, x4, x5, x6, x7, x8;
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/* shortcut */
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if (!((x1 = (blk[8 * 4] << 8)) | (x2 = blk[8 * 6]) | (x3 = blk[8 * 2]) |
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(x4 = blk[8 * 1]) | (x5 = blk[8 * 7]) | (x6 = blk[8 * 5]) |
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(x7 = blk[8 * 3])))
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{
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blk[8 * 0] = blk[8 * 1] = blk[8 * 2] = blk[8 * 3]
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= blk[8 * 4] = blk[8 * 5] = blk[8 * 6]
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= blk[8 * 7] = ((blk[8 * 0] + 32) >>6);
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return;
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}
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x0 = (blk[8 * 0] << 8) + 16384;
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/* first stage */
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x8 = W7 * (x4 + x5) + 4;
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x4 = (x8 + (W1 - W7) * x4) >> 3;
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x5 = (x8 - (W1 + W7) * x5) >> 3;
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x8 = W3 * (x6 + x7) + 4;
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x6 = (x8 - (W3 - W5) * x6) >> 3;
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x7 = (x8 - (W3 + W5) * x7) >> 3;
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/* second stage */
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x8 = x0 + x1;
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x0 -= x1;
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x1 = W6 * (x3 + x2) + 4;
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x2 = (x1 - (W2 + W6) * x2) >> 3;
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x3 = (x1 + (W2 - W6) * x3) >> 3;
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x1 = x4 + x6;
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x4 -= x6;
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x6 = x5 + x7;
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x5 -= x7;
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/* third stage */
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x7 = x8 + x3;
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x8 -= x3;
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x3 = x0 + x2;
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x0 -= x2;
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x2 = (181 * (x4 + x5) + 128) >> 8;
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x4 = (181 * (x4 - x5) + 128) >> 8;
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/* fourth stage */
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blk[8 * 0] = (x7 + x1 ) >> 14;
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blk[8 * 1] = (x3 + x2 ) >> 14;
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blk[8 * 2] = (x0 + x4 ) >> 14;
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blk[8 * 3] = (x8 + x6 ) >> 14;
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blk[8 * 4] = (x8 - x6 ) >> 14;
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blk[8 * 5] = (x0 - x4 ) >> 14;
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blk[8 * 6] = (x3 - x2 ) >> 14;
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blk[8 * 7] = (x7 - x1 ) >> 14;
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}
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#define TX_DIM 8
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void vp8_short_idct8x8_c(short *coefs, short *block, int pitch)
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{
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int X[TX_DIM*TX_DIM];
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int i,j;
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int shortpitch = pitch >> 1;
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for (i = 0; i < TX_DIM; i++)
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{
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for (j = 0; j < TX_DIM; j++)
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{
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X[i * TX_DIM + j] = (int)(coefs[i * TX_DIM + j]+1
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+ (coefs[i * TX_DIM + j]<0))>>2;
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}
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}
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for (i = 0; i < 8; i++)
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idctrow (X + 8 * i);
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for (i = 0; i < 8; i++)
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idctcol (X + i);
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for (i = 0; i < TX_DIM; i++)
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{
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for (j = 0; j < TX_DIM; j++)
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{
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block[i*shortpitch+j] = X[i * TX_DIM + j]>>1;
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}
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}
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}
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void vp8_short_ihaar2x2_c(short *input, short *output, int pitch)
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{
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int i, x;
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short *ip = input; //0,1, 4, 8
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short *op = output;
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for (i = 0; i < 16; i++)
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{
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op[i] = 0;
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}
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op[0] = (ip[0] + ip[1] + ip[4] + ip[8] + 1)>>1;
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op[1] = (ip[0] - ip[1] + ip[4] - ip[8])>>1;
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op[4] = (ip[0] + ip[1] - ip[4] - ip[8])>>1;
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op[8] = (ip[0] - ip[1] - ip[4] + ip[8])>>1;
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}
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