/* * idct.c * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org> * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca> * * This file is part of mpeg2dec, a free MPEG-2 video stream decoder. * See http://libmpeg2.sourceforge.net/ for updates. * * 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 */#include "config.h"#include <stdlib.h>#include <inttypes.h>#include "mpeg2.h"#include "attributes.h"#include "mpeg2_internal.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 (* mpeg2_idct_copy) (int16_t * block, uint8_t * dest, int stride);void (* mpeg2_idct_add) (int last, int16_t * block,			 uint8_t * dest, int stride);/* * In legal streams, the IDCT output should be between -384 and +384. * In corrupted streams, it is possible to force the IDCT output to go * to +-3826 - this is the worst case for a column IDCT where the * column inputs are 16-bit values. */uint8_t mpeg2_clip[3840 * 2 + 256];#define CLIP(i) ((mpeg2_clip + 3840)[i])#if 0#define BUTTERFLY(t0,t1,W0,W1,d0,d1)	\do {					\    t0 = W0 * d0 + W1 * d1;		\    t1 = W0 * d1 - W1 * d0;		\} while (0)#else#define BUTTERFLY(t0,t1,W0,W1,d0,d1)	\do {					\    int tmp = W0 * (d0 + d1);		\    t0 = tmp + (W1 - W0) * d1;		\    t1 = tmp - (W1 + W0) * d0;		\} while (0)#endifstatic void inline idct_row (int16_t * const block){    int d0, d1, d2, d3;    int a0, a1, a2, a3, b0, b1, b2, b3;    int t0, t1, t2, t3;    /* shortcut */    if (likely (!(block[1] | ((int32_t *)block)[1] | ((int32_t *)block)[2] |		  ((int32_t *)block)[3]))) {	uint32_t tmp = (uint16_t) (block[0] >> 1);	tmp |= tmp << 16;	((int32_t *)block)[0] = tmp;	((int32_t *)block)[1] = tmp;	((int32_t *)block)[2] = tmp;	((int32_t *)block)[3] = tmp;	return;    }    d0 = (block[0] << 11) + 2048;    d1 = block[1];    d2 = block[2] << 11;    d3 = block[3];    t0 = d0 + d2;    t1 = d0 - d2;    BUTTERFLY (t2, t3, W6, W2, d3, d1);    a0 = t0 + t2;    a1 = t1 + t3;    a2 = t1 - t3;    a3 = t0 - t2;    d0 = block[4];    d1 = block[5];    d2 = block[6];    d3 = block[7];    BUTTERFLY (t0, t1, W7, W1, d3, d0);    BUTTERFLY (t2, t3, W3, W5, d1, d2);    b0 = t0 + t2;    b3 = t1 + t3;    t0 -= t2;    t1 -= t3;    b1 = ((t0 + t1) >> 8) * 181;    b2 = ((t0 - t1) >> 8) * 181;    block[0] = (a0 + b0) >> 12;    block[1] = (a1 + b1) >> 12;    block[2] = (a2 + b2) >> 12;    block[3] = (a3 + b3) >> 12;    block[4] = (a3 - b3) >> 12;    block[5] = (a2 - b2) >> 12;    block[6] = (a1 - b1) >> 12;    block[7] = (a0 - b0) >> 12;}static void inline idct_col (int16_t * const block){    int d0, d1, d2, d3;    int a0, a1, a2, a3, b0, b1, b2, b3;    int t0, t1, t2, t3;    d0 = (block[8*0] << 11) + 65536;    d1 = block[8*1];    d2 = block[8*2] << 11;    d3 = block[8*3];    t0 = d0 + d2;    t1 = d0 - d2;    BUTTERFLY (t2, t3, W6, W2, d3, d1);    a0 = t0 + t2;    a1 = t1 + t3;    a2 = t1 - t3;    a3 = t0 - t2;    d0 = block[8*4];    d1 = block[8*5];    d2 = block[8*6];    d3 = block[8*7];    BUTTERFLY (t0, t1, W7, W1, d3, d0);    BUTTERFLY (t2, t3, W3, W5, d1, d2);    b0 = t0 + t2;    b3 = t1 + t3;    t0 -= t2;    t1 -= t3;    b1 = ((t0 + t1) >> 8) * 181;    b2 = ((t0 - t1) >> 8) * 181;    block[8*0] = (a0 + b0) >> 17;    block[8*1] = (a1 + b1) >> 17;    block[8*2] = (a2 + b2) >> 17;    block[8*3] = (a3 + b3) >> 17;    block[8*4] = (a3 - b3) >> 17;    block[8*5] = (a2 - b2) >> 17;    block[8*6] = (a1 - b1) >> 17;    block[8*7] = (a0 - b0) >> 17;}static void mpeg2_idct_copy_c (int16_t * block, uint8_t * dest,			       const 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);    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]);	((int32_t *)block)[0] = 0;	((int32_t *)block)[1] = 0;	((int32_t *)block)[2] = 0;	((int32_t *)block)[3] = 0;	dest += stride;	block += 8;    } while (--i);}static void mpeg2_idct_add_c (const int last, int16_t * block,			      uint8_t * dest, const int stride){    int i;    if (last != 129 || (block[0] & (7 << 4)) == (4 << 4)) {	for (i = 0; i < 8; i++)	    idct_row (block + 8 * i);	for (i = 0; i < 8; i++)	    idct_col (block + i);	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]);	    ((int32_t *)block)[0] = 0;	((int32_t *)block)[1] = 0;	    ((int32_t *)block)[2] = 0;	((int32_t *)block)[3] = 0;	    dest += stride;	    block += 8;	} while (--i);    } else {	int DC;	DC = (block[0] + 64) >> 7;	block[0] = block[63] = 0;	i = 8;	do {	    dest[0] = CLIP (DC + dest[0]);	    dest[1] = CLIP (DC + dest[1]);	    dest[2] = CLIP (DC + dest[2]);	    dest[3] = CLIP (DC + dest[3]);	    dest[4] = CLIP (DC + dest[4]);	    dest[5] = CLIP (DC + dest[5]);	    dest[6] = CLIP (DC + dest[6]);	    dest[7] = CLIP (DC + dest[7]);	    dest += stride;	} while (--i);    }}void mpeg2_idct_init (uint32_t accel){#ifdef ARCH_X86    if (accel & MPEG2_ACCEL_X86_MMXEXT) {	mpeg2_idct_copy = mpeg2_idct_copy_mmxext;	mpeg2_idct_add = mpeg2_idct_add_mmxext;	mpeg2_idct_mmx_init ();    } else if (accel & MPEG2_ACCEL_X86_MMX) {	mpeg2_idct_copy = mpeg2_idct_copy_mmx;	mpeg2_idct_add = mpeg2_idct_add_mmx;	mpeg2_idct_mmx_init ();    } else#endif#ifdef ARCH_PPC    if (accel & MPEG2_ACCEL_PPC_ALTIVEC) {	mpeg2_idct_copy = mpeg2_idct_copy_altivec;	mpeg2_idct_add = mpeg2_idct_add_altivec;	mpeg2_idct_altivec_init ();    } else#endif#ifdef ARCH_ALPHA    if (accel & MPEG2_ACCEL_ALPHA_MVI) {	mpeg2_idct_copy = mpeg2_idct_copy_mvi;	mpeg2_idct_add = mpeg2_idct_add_mvi;	mpeg2_idct_alpha_init ();    } else if (accel & MPEG2_ACCEL_ALPHA) {	int i;	mpeg2_idct_copy = mpeg2_idct_copy_alpha;	mpeg2_idct_add = mpeg2_idct_add_alpha;	mpeg2_idct_alpha_init ();	for (i = -3840; i < 3840 + 256; i++)	    CLIP(i) = (i < 0) ? 0 : ((i > 255) ? 255 : i);    } else#endif    {	extern uint8_t mpeg2_scan_norm[64];	extern uint8_t mpeg2_scan_alt[64];	int i, j;	mpeg2_idct_copy = mpeg2_idct_copy_c;	mpeg2_idct_add = mpeg2_idct_add_c;	for (i = -3840; i < 3840 + 256; i++)	    CLIP(i) = (i < 0) ? 0 : ((i > 255) ? 255 : i);	for (i = 0; i < 64; i++) {	    j = mpeg2_scan_norm[i];	    mpeg2_scan_norm[i] = ((j & 0x36) >> 1) | ((j & 0x09) << 2);	    j = mpeg2_scan_alt[i];	    mpeg2_scan_alt[i] = ((j & 0x36) >> 1) | ((j & 0x09) << 2);	}    }}