aom/vp8/encoder/dct.c

117 строки
2.5 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.
*/
#include <math.h>
void vp8_short_fdct4x4_c(short *input, short *output, int pitch)
{
int i;
int a1, b1, c1, d1;
short *ip = input;
short *op = output;
for (i = 0; i < 4; i++)
{
a1 = ((ip[0] + ip[3])<<3);
b1 = ((ip[1] + ip[2])<<3);
c1 = ((ip[1] - ip[2])<<3);
d1 = ((ip[0] - ip[3])<<3);
op[0] = a1 + b1;
op[2] = a1 - b1;
op[1] = (c1 * 2217 + d1 * 5352 + 14500)>>12;
op[3] = (d1 * 2217 - c1 * 5352 + 7500)>>12;
ip += pitch / 2;
op += 4;
}
ip = output;
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 + 7)>>4;
op[8] = ( a1 - b1 + 7)>>4;
op[4] =((c1 * 2217 + d1 * 5352 + 12000)>>16) + (d1!=0);
op[12] = (d1 * 2217 - c1 * 5352 + 51000)>>16;
ip++;
op++;
}
}
void vp8_short_fdct8x4_c(short *input, short *output, int pitch)
{
vp8_short_fdct4x4_c(input, output, pitch);
vp8_short_fdct4x4_c(input + 4, output + 16, pitch);
}
void vp8_short_walsh4x4_c(short *input, short *output, int pitch)
{
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[2])<<2);
d1 = ((ip[1] + ip[3])<<2);
c1 = ((ip[1] - ip[3])<<2);
b1 = ((ip[0] - ip[2])<<2);
op[0] = a1 + d1 + (a1!=0);
op[1] = b1 + c1;
op[2] = b1 - c1;
op[3] = a1 - d1;
ip += pitch / 2;
op += 4;
}
ip = output;
op = output;
for (i = 0; i < 4; i++)
{
a1 = ip[0] + ip[8];
d1 = ip[4] + ip[12];
c1 = ip[4] - ip[12];
b1 = ip[0] - ip[8];
a2 = a1 + d1;
b2 = b1 + c1;
c2 = b1 - c1;
d2 = a1 - d1;
a2 += a2<0;
b2 += b2<0;
c2 += c2<0;
d2 += d2<0;
op[0] = (a2+3) >> 3;
op[4] = (b2+3) >> 3;
op[8] = (c2+3) >> 3;
op[12]= (d2+3) >> 3;
ip++;
op++;
}
}