Electronic Arts TGQ/TQI/MAD IDCT algorithm
[libav.git] / libavcodec / eaidct.c
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28245435
PR
1/*
2 * Electronic Arts TGQ/TQI/MAD IDCT algorithm
3 * Copyright (c) 2007-2008 Peter Ross <pross@xvid.org>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file eaidct.c
24 * Electronic Arts TGQ/TQI/MAD IDCT algorithm
25 * @author Peter Ross <pross@xvid.org>
26 */
27
28#include "dsputil.h"
29
30#define ASQRT 181 /* (1/sqrt(2))<<8 */
31#define A4 669 /* cos(pi/8)*sqrt(2)<<9 */
32#define A2 277 /* sin(pi/8)*sqrt(2)<<9 */
33#define A5 196 /* sin(pi/8)<<9 */
34
35#define IDCT_TRANSFORM(dest,s0,s1,s2,s3,s4,s5,s6,s7,d0,d1,d2,d3,d4,d5,d6,d7,munge,src) {\
36 const int a1 = (src)[s1] + (src)[s7]; \
37 const int a7 = (src)[s1] - (src)[s7]; \
38 const int a5 = (src)[s5] + (src)[s3]; \
39 const int a3 = (src)[s5] - (src)[s3]; \
40 const int a2 = (src)[s2] + (src)[s6]; \
41 const int a6 = (ASQRT*((src)[s2] - (src)[s6]))>>8; \
42 const int a0 = (src)[s0] + (src)[s4]; \
43 const int a4 = (src)[s0] - (src)[s4]; \
44 const int b0 = (((A4-A5)*a7 - A5*a3)>>9) + a1+a5; \
45 const int b1 = (((A4-A5)*a7 - A5*a3)>>9) + ((ASQRT*(a1-a5))>>8); \
46 const int b2 = (((A2+A5)*a3 + A5*a7)>>9) + ((ASQRT*(a1-a5))>>8); \
47 const int b3 = ((A2+A5)*a3 + A5*a7)>>9; \
48 (dest)[d0] = munge(a0+a2+a6+b0); \
49 (dest)[d1] = munge(a4+a6 +b1); \
50 (dest)[d2] = munge(a4-a6 +b2); \
51 (dest)[d3] = munge(a0-a2-a6+b3); \
52 (dest)[d4] = munge(a0-a2-a6-b3); \
53 (dest)[d5] = munge(a4-a6 -b2); \
54 (dest)[d6] = munge(a4+a6 -b1); \
55 (dest)[d7] = munge(a0+a2+a6-b0); \
56}
57/* end IDCT_TRANSFORM macro */
58
59#define MUNGE_NONE(x) (x)
60#define IDCT_COL(dest,src) IDCT_TRANSFORM(dest,0,8,16,24,32,40,48,56,0,8,16,24,32,40,48,56,MUNGE_NONE,src)
61
62#define MUNGE_8BIT(x) av_clip_uint8((x)>>4)
63#define IDCT_ROW(dest,src) IDCT_TRANSFORM(dest,0,1,2,3,4,5,6,7,0,1,2,3,4,5,6,7,MUNGE_8BIT,src)
64
65static inline void ea_idct_col(DCTELEM *dest, const DCTELEM *src) {
66 if ((src[8]|src[16]|src[24]|src[32]|src[40]|src[48]|src[56])==0) {
67 dest[0] =
68 dest[8] =
69 dest[16] =
70 dest[24] =
71 dest[32] =
72 dest[40] =
73 dest[48] =
74 dest[56] = src[0];
75 }else
76 IDCT_COL(dest, src);
77}
78
79void ff_ea_idct_put_c(uint8_t *dest, int linesize, DCTELEM *block) {
80 int i;
81 DCTELEM temp[64];
82 block[0] += 4;
83 for (i=0; i<8; i++)
84 ea_idct_col(&temp[i], &block[i]);
85 for (i=0; i<8; i++)
86 IDCT_ROW( (&dest[i*linesize]), (&temp[8*i]) );
87}