Libav
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00001 /* 00002 * Electronic Arts TGQ/TQI/MAD IDCT algorithm 00003 * Copyright (c) 2007-2008 Peter Ross <pross@xvid.org> 00004 * 00005 * This file is part of FFmpeg. 00006 * 00007 * FFmpeg is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * FFmpeg is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with FFmpeg; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00028 #include "dsputil.h" 00029 00030 #define ASQRT 181 /* (1/sqrt(2))<<8 */ 00031 #define A4 669 /* cos(pi/8)*sqrt(2)<<9 */ 00032 #define A2 277 /* sin(pi/8)*sqrt(2)<<9 */ 00033 #define A5 196 /* sin(pi/8)<<9 */ 00034 00035 #define IDCT_TRANSFORM(dest,s0,s1,s2,s3,s4,s5,s6,s7,d0,d1,d2,d3,d4,d5,d6,d7,munge,src) {\ 00036 const int a1 = (src)[s1] + (src)[s7]; \ 00037 const int a7 = (src)[s1] - (src)[s7]; \ 00038 const int a5 = (src)[s5] + (src)[s3]; \ 00039 const int a3 = (src)[s5] - (src)[s3]; \ 00040 const int a2 = (src)[s2] + (src)[s6]; \ 00041 const int a6 = (ASQRT*((src)[s2] - (src)[s6]))>>8; \ 00042 const int a0 = (src)[s0] + (src)[s4]; \ 00043 const int a4 = (src)[s0] - (src)[s4]; \ 00044 const int b0 = (((A4-A5)*a7 - A5*a3)>>9) + a1+a5; \ 00045 const int b1 = (((A4-A5)*a7 - A5*a3)>>9) + ((ASQRT*(a1-a5))>>8); \ 00046 const int b2 = (((A2+A5)*a3 + A5*a7)>>9) + ((ASQRT*(a1-a5))>>8); \ 00047 const int b3 = ((A2+A5)*a3 + A5*a7)>>9; \ 00048 (dest)[d0] = munge(a0+a2+a6+b0); \ 00049 (dest)[d1] = munge(a4+a6 +b1); \ 00050 (dest)[d2] = munge(a4-a6 +b2); \ 00051 (dest)[d3] = munge(a0-a2-a6+b3); \ 00052 (dest)[d4] = munge(a0-a2-a6-b3); \ 00053 (dest)[d5] = munge(a4-a6 -b2); \ 00054 (dest)[d6] = munge(a4+a6 -b1); \ 00055 (dest)[d7] = munge(a0+a2+a6-b0); \ 00056 } 00057 /* end IDCT_TRANSFORM macro */ 00058 00059 #define MUNGE_NONE(x) (x) 00060 #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) 00061 00062 #define MUNGE_8BIT(x) av_clip_uint8((x)>>4) 00063 #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) 00064 00065 static inline void ea_idct_col(DCTELEM *dest, const DCTELEM *src) { 00066 if ((src[8]|src[16]|src[24]|src[32]|src[40]|src[48]|src[56])==0) { 00067 dest[0] = 00068 dest[8] = 00069 dest[16] = 00070 dest[24] = 00071 dest[32] = 00072 dest[40] = 00073 dest[48] = 00074 dest[56] = src[0]; 00075 }else 00076 IDCT_COL(dest, src); 00077 } 00078 00079 void ff_ea_idct_put_c(uint8_t *dest, int linesize, DCTELEM *block) { 00080 int i; 00081 DCTELEM temp[64]; 00082 block[0] += 4; 00083 for (i=0; i<8; i++) 00084 ea_idct_col(&temp[i], &block[i]); 00085 for (i=0; i<8; i++) 00086 IDCT_ROW( (&dest[i*linesize]), (&temp[8*i]) ); 00087 }