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/*
* Copyright (c) 2016, Alliance for Open Media. All rights reserved
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/
#include <assert.h>
#include "aom_dsp/txfm_common.h"
#include "config/aom_dsp_rtcd.h"
void aom_fdct8x8_c(const int16_t *input, tran_low_t *final_output, int stride) {
int i, j;
tran_low_t intermediate[64];
int pass;
tran_low_t *output = intermediate;
const tran_low_t *in = NULL;
// Transform columns
for (pass = 0; pass < 2; ++pass) {
tran_high_t s0, s1, s2, s3, s4, s5, s6, s7; // canbe16
tran_high_t t0, t1, t2, t3; // needs32
tran_high_t x0, x1, x2, x3; // canbe16
for (i = 0; i < 8; i++) {
// stage 1
if (pass == 0) {
s0 = (input[0 * stride] + input[7 * stride]) * 4;
s1 = (input[1 * stride] + input[6 * stride]) * 4;
s2 = (input[2 * stride] + input[5 * stride]) * 4;
s3 = (input[3 * stride] + input[4 * stride]) * 4;
s4 = (input[3 * stride] - input[4 * stride]) * 4;
s5 = (input[2 * stride] - input[5 * stride]) * 4;
s6 = (input[1 * stride] - input[6 * stride]) * 4;
s7 = (input[0 * stride] - input[7 * stride]) * 4;
++input;
} else {
s0 = in[0 * 8] + in[7 * 8];
s1 = in[1 * 8] + in[6 * 8];
s2 = in[2 * 8] + in[5 * 8];
s3 = in[3 * 8] + in[4 * 8];
s4 = in[3 * 8] - in[4 * 8];
s5 = in[2 * 8] - in[5 * 8];
s6 = in[1 * 8] - in[6 * 8];
s7 = in[0 * 8] - in[7 * 8];
++in;
}
// fdct4(step, step);
x0 = s0 + s3;
x1 = s1 + s2;
x2 = s1 - s2;
x3 = s0 - s3;
t0 = (x0 + x1) * cospi_16_64;
t1 = (x0 - x1) * cospi_16_64;
t2 = x2 * cospi_24_64 + x3 * cospi_8_64;
t3 = -x2 * cospi_8_64 + x3 * cospi_24_64;
output[0] = (tran_low_t)fdct_round_shift(t0);
output[2] = (tran_low_t)fdct_round_shift(t2);
output[4] = (tran_low_t)fdct_round_shift(t1);
output[6] = (tran_low_t)fdct_round_shift(t3);
// Stage 2
t0 = (s6 - s5) * cospi_16_64;
t1 = (s6 + s5) * cospi_16_64;
t2 = fdct_round_shift(t0);
t3 = fdct_round_shift(t1);
// Stage 3
x0 = s4 + t2;
x1 = s4 - t2;
x2 = s7 - t3;
x3 = s7 + t3;
// Stage 4
t0 = x0 * cospi_28_64 + x3 * cospi_4_64;
t1 = x1 * cospi_12_64 + x2 * cospi_20_64;
t2 = x2 * cospi_12_64 + x1 * -cospi_20_64;
t3 = x3 * cospi_28_64 + x0 * -cospi_4_64;
output[1] = (tran_low_t)fdct_round_shift(t0);
output[3] = (tran_low_t)fdct_round_shift(t2);
output[5] = (tran_low_t)fdct_round_shift(t1);
output[7] = (tran_low_t)fdct_round_shift(t3);
output += 8;
}
in = intermediate;
output = final_output;
}
// Rows
for (i = 0; i < 8; ++i) {
for (j = 0; j < 8; ++j) final_output[j + i * 8] /= 2;
}
}
void aom_highbd_fdct8x8_c(const int16_t *input, tran_low_t *final_output,
int stride) {
aom_fdct8x8_c(input, final_output, stride);
}
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