/* * idct.c * Copyright (C) 1999-2000 Aaron Holtzman * * Portions of this code are from the MPEG software simulation group * idct implementation. This code will be replaced with a new * implementation soon. * * This file is part of mpeg2dec, a free MPEG-2 video stream decoder. * * mpeg2dec is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * mpeg2dec is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /**********************************************************/ /* inverse two dimensional DCT, Chen-Wang algorithm */ /* (cf. IEEE ASSP-32, pp. 803-816, Aug. 1984) */ /* 32-bit integer arithmetic (8 bit coefficients) */ /* 11 mults, 29 adds per DCT */ /* sE, 18.8.91 */ /**********************************************************/ /* coefficients extended to 12 bit for IEEE1180-1990 */ /* compliance sE, 2.1.94 */ /**********************************************************/ /* this code assumes >> to be a two's-complement arithmetic */ /* right shift: (-2)>>1 == -1 , (-3)>>1 == -2 */ #include "config.h" #include #include #include "mpeg2_internal.h" #include "mm_accel.h" #define W1 2841 /* 2048*sqrt (2)*cos (1*pi/16) */ #define W2 2676 /* 2048*sqrt (2)*cos (2*pi/16) */ #define W3 2408 /* 2048*sqrt (2)*cos (3*pi/16) */ #define W5 1609 /* 2048*sqrt (2)*cos (5*pi/16) */ #define W6 1108 /* 2048*sqrt (2)*cos (6*pi/16) */ #define W7 565 /* 2048*sqrt (2)*cos (7*pi/16) */ // idct main entry point void (*idct_block_copy) (int16_t * block, uint8_t * dest, int stride); void (*idct_block_add) (int16_t * block, uint8_t * dest, int stride); static void idct_block_copy_c (int16_t *block, uint8_t * dest, int stride); static void idct_block_add_c (int16_t *block, uint8_t * dest, int stride); static uint8_t clip_lut[1024]; #define CLIP(i) ((clip_lut+384)[ (i)]) void idct_init (void) { #ifdef ARCH_X86 if (config.flags & MM_ACCEL_X86_MMXEXT) { fprintf (stderr, "Using MMXEXT for IDCT transform\n"); idct_block_copy = idct_block_copy_mmxext; idct_block_add = idct_block_add_mmxext; idct_mmx_init (); } else if (config.flags & MM_ACCEL_X86_MMX) { fprintf (stderr, "Using MMX for IDCT transform\n"); idct_block_copy = idct_block_copy_mmx; idct_block_add = idct_block_add_mmx; idct_mmx_init (); } else #endif #ifdef LIBMPEG2_MLIB if (config.flags & MM_ACCEL_MLIB) { fprintf (stderr, "Using mlib for IDCT transform\n"); idct_block_copy = idct_block_copy_mlib; idct_block_add = idct_block_add_mlib; } else #endif { int i; fprintf (stderr, "No accelerated IDCT transform found\n"); idct_block_copy = idct_block_copy_c; idct_block_add = idct_block_add_c; for (i = -384; i < 640; i++) clip_lut[i+384] = (i < 0) ? 0 : ((i > 255) ? 255 : i); } } /* row (horizontal) IDCT * * 7 pi 1 * dst[k] = sum c[l] * src[l] * cos ( -- * ( k + - ) * l ) * l=0 8 2 * * where: c[0] = 128 * c[1..7] = 128*sqrt (2) */ static void inline idct_row (int16_t * block) { int x0, x1, x2, x3, x4, x5, x6, x7, x8; x1 = block[4] << 11; x2 = block[6]; x3 = block[2]; x4 = block[1]; x5 = block[7]; x6 = block[5]; x7 = block[3]; /* shortcut */ if (! (x1 | x2 | x3 | x4 | x5 | x6 | x7 )) { block[0] = block[1] = block[2] = block[3] = block[4] = block[5] = block[6] = block[7] = block[0]<<3; return; } x0 = (block[0] << 11) + 128; /* for proper rounding in the fourth stage */ /* first stage */ x8 = W7 * (x4 + x5); x4 = x8 + (W1 - W7) * x4; x5 = x8 - (W1 + W7) * x5; x8 = W3 * (x6 + x7); x6 = x8 - (W3 - W5) * x6; x7 = x8 - (W3 + W5) * x7; /* second stage */ x8 = x0 + x1; x0 -= x1; x1 = W6 * (x3 + x2); x2 = x1 - (W2 + W6) * x2; x3 = x1 + (W2 - W6) * x3; x1 = x4 + x6; x4 -= x6; x6 = x5 + x7; x5 -= x7; /* third stage */ x7 = x8 + x3; x8 -= x3; x3 = x0 + x2; x0 -= x2; x2 = (181 * (x4 + x5) + 128) >> 8; x4 = (181 * (x4 - x5) + 128) >> 8; /* fourth stage */ block[0] = (x7 + x1) >> 8; block[1] = (x3 + x2) >> 8; block[2] = (x0 + x4) >> 8; block[3] = (x8 + x6) >> 8; block[4] = (x8 - x6) >> 8; block[5] = (x0 - x4) >> 8; block[6] = (x3 - x2) >> 8; block[7] = (x7 - x1) >> 8; } /* column (vertical) IDCT * * 7 pi 1 * dst[8*k] = sum c[l] * src[8*l] * cos ( -- * ( k + - ) * l ) * l=0 8 2 * * where: c[0] = 1/1024 * c[1..7] = (1/1024)*sqrt (2) */ static void inline idct_col (int16_t *block) { int x0, x1, x2, x3, x4, x5, x6, x7, x8; /* shortcut */ x1 = block [8*4] << 8; x2 = block [8*6]; x3 = block [8*2]; x4 = block [8*1]; x5 = block [8*7]; x6 = block [8*5]; x7 = block [8*3]; #if 0 if (! (x1 | x2 | x3 | x4 | x5 | x6 | x7 )) { block[8*0] = block[8*1] = block[8*2] = block[8*3] = block[8*4] = block[8*5] = block[8*6] = block[8*7] = (block[8*0] + 32) >> 6; return; } #endif x0 = (block[8*0] << 8) + 8192; /* first stage */ x8 = W7 * (x4 + x5) + 4; x4 = (x8 + (W1 - W7) * x4) >> 3; x5 = (x8 - (W1 + W7) * x5) >> 3; x8 = W3 * (x6 + x7) + 4; x6 = (x8 - (W3 - W5) * x6) >> 3; x7 = (x8 - (W3 + W5) * x7) >> 3; /* second stage */ x8 = x0 + x1; x0 -= x1; x1 = W6 * (x3 + x2) + 4; x2 = (x1 - (W2 + W6) * x2) >> 3; x3 = (x1 + (W2 - W6) * x3) >> 3; x1 = x4 + x6; x4 -= x6; x6 = x5 + x7; x5 -= x7; /* third stage */ x7 = x8 + x3; x8 -= x3; x3 = x0 + x2; x0 -= x2; x2 = (181 * (x4 + x5) + 128) >> 8; x4 = (181 * (x4 - x5) + 128) >> 8; /* fourth stage */ block[8*0] = (x7 + x1) >> 14; block[8*1] = (x3 + x2) >> 14; block[8*2] = (x0 + x4) >> 14; block[8*3] = (x8 + x6) >> 14; block[8*4] = (x8 - x6) >> 14; block[8*5] = (x0 - x4) >> 14; block[8*6] = (x3 - x2) >> 14; block[8*7] = (x7 - x1) >> 14; } void idct_block_copy_c (int16_t * block, uint8_t * dest, int stride) { int i; for (i = 0; i < 8; i++) idct_row (block + 8 * i); for (i = 0; i < 8; i++) idct_col (block + i); i = 8; do { dest[0] = CLIP (block[0]); dest[1] = CLIP (block[1]); dest[2] = CLIP (block[2]); dest[3] = CLIP (block[3]); dest[4] = CLIP (block[4]); dest[5] = CLIP (block[5]); dest[6] = CLIP (block[6]); dest[7] = CLIP (block[7]); dest += stride; block += 8; } while (--i); } void idct_block_add_c (int16_t * block, uint8_t * dest, int stride) { int i; for (i = 0; i < 8; i++) idct_row (block + 8 * i); for (i = 0; i < 8; i++) idct_col (block + i); i = 8; do { dest[0] = CLIP (block[0] + dest[0]); dest[1] = CLIP (block[1] + dest[1]); dest[2] = CLIP (block[2] + dest[2]); dest[3] = CLIP (block[3] + dest[3]); dest[4] = CLIP (block[4] + dest[4]); dest[5] = CLIP (block[5] + dest[5]); dest[6] = CLIP (block[6] + dest[6]); dest[7] = CLIP (block[7] + dest[7]); dest += stride; block += 8; } while (--i); }