media/video/libvpx/vp8_dct4x4_ref.c

   1 /*
   2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11 #include <math.h>
  12 #include <stdint.h>
  13 #include <stdio.h>
  14
  15 #include "vp8_rtcd.h"
  16
  17 void vp8_short_fdct4x4_c(int16_t *input, int16_t *output, int32_t pitch) {
  18   int i;
  19   int a1, b1, c1, d1;
  20   short *ip = input;
  21   short *op = output;
  22
  23   for (i = 0; i < 4; ++i) {
  24     a1 = ((ip[0] + ip[3]));
  25     b1 = ((ip[1] + ip[2]));
  26     c1 = ((ip[1] - ip[2]));
  27     d1 = ((ip[0] - ip[3]));
  28
  29     a1 *= 8;
  30     b1 *= 8;
  31     c1 *= 8;
  32     d1 *= 8;
  33     //printf("a1 = %08x\tb1 = %08x\tc1 = %08x\td1 = %08x\n", a1, b1, c1, d1);
  34
  35     op[0] = a1 + b1;
  36     op[2] = a1 - b1;
  37     //printf("op[0] = %04x\top[2] = %04x\n", (uint16_t)op[0], (uint16_t)op[2]);
  38
  39     op[1] = (c1 * 2217 + d1 * 5352 + 14500) >> 12;
  40     op[3] = (d1 * 2217 - c1 * 5352 + 7500) >> 12;
  41     //printf("op[1] = %04x\top[3] = %04x\n", (uint16_t)op[1], (uint16_t)op[3]);
  42
  43     ip += pitch / 2;
  44     op += 4;
  45   }
  46   ip = output;
  47   op = output;
  48   for (i = 0; i < 4; ++i) {
  49     a1 = ip[0] + ip[12];
  50     b1 = ip[4] + ip[8];
  51     c1 = ip[4] - ip[8];
  52     d1 = ip[0] - ip[12];
  53     //printf("a1 = %08x\tb1 = %08x\tc1 = %08x\td1 = %08x\n", a1, b1, c1, d1);
  54
  55     op[0] = (a1 + b1 + 7) >> 4;
  56     op[8] = (a1 - b1 + 7) >> 4;
  57     //printf("op[%d] = %08x\top[%d] = %08x\n", i, op[0], i+8, op[8]);
  58
  59     op[4] = ((c1 * 2217 + d1 * 5352 + 12000) >> 16) + (d1 != 0);
  60     op[12] = (d1 * 2217 - c1 * 5352 + 51000) >> 16;
  61     //printf("op[%d] = %04x\top[%d] = %04x\n", i+4, (uint16_t)op[4], i+12, (uint16_t)op[12]);
  62
  63     ip++;
  64     op++;
  65   }
  66 }