sad.c

MPEG-4编解码的实现(包括MPEG4视音频编解码)

/**************************************************************************
 *
 *	XVID MPEG-4 VIDEO CODEC
 *	sum of absolute difference
 *
 *	This program is an implementation of a part of one or more MPEG-4
 *	Video tools as specified in ISO/IEC 14496-2 standard.  Those intending
 *	to use this software module in hardware or software products are
 *	advised that its use may infringe existing patents or copyrights, and
 *	any such use would be at such party's own risk.  The original
 *	developer of this software module and his/her company, and subsequent
 *	editors and their companies, will have no liability for use of this
 *	software or modifications or derivatives thereof.
 *
 *	This program 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.
 *
 *	This program 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *************************************************************************/

/**************************************************************************
 *
 *	History:
 *
 *	10.11.2001	initial version; (c)2001 peter ross <[e-mail]>
 *
 *************************************************************************/


#include "../portab.h"
#include "sad.h"

sad16FuncPtr sad16;
sad8FuncPtr sad8;
dev16FuncPtr dev16;

sadInitFuncPtr sadInit;

#define ABS(X) (((X)>0)?(X):-(X))

uint32_t sad16_c(const uint8_t * const cur,
		 const uint8_t * const ref,
		 const uint32_t stride,
		 const uint32_t best_sad)
{

	uint32_t sad = 0;
	uint32_t i,j;
	uint8_t const *ptr_cur = cur;
	uint8_t const *ptr_ref = ref;

	for (j = 0; j < 16; j++) {

		for (i = 0; i < 16; i++) {

			sad += ABS(*(ptr_cur + i) - *(ptr_ref + i));

			if (sad >= best_sad) {
				return sad;
			}


		}

		ptr_cur += stride;
		ptr_ref += stride;

	}

	return sad;

}



uint32_t sad8_c(const uint8_t * const cur,
					const uint8_t * const ref,
					const uint32_t stride)
{
	uint32_t sad = 0;
	uint32_t i,j;
	uint8_t const *ptr_cur = cur;
	uint8_t const *ptr_ref = ref;

	for (j = 0; j < 8; j++) {

		for (i = 0; i < 8; i++) {
			sad += ABS(*(ptr_cur + i) - *(ptr_ref + i));
		}

		ptr_cur += stride;
		ptr_ref += stride;

	}

	return sad;
}




/* average deviation from mean */

uint32_t dev16_c(const uint8_t * const cur,
				const uint32_t stride)
{

	uint32_t mean = 0;
	uint32_t dev = 0;
	uint32_t i,j;
	uint8_t const *ptr_cur = cur;

	for (j = 0; j < 16; j++) {

		for (i = 0; i < 16; i++)
			mean += *(ptr_cur + i);

		ptr_cur += stride;

	}

	mean /= (16 * 16);
	ptr_cur = cur;

	for (j = 0; j < 16; j++) {

		for (i = 0; i < 16; i++)
			dev += ABS(*(ptr_cur + i) - (int32_t)mean);

		ptr_cur += stride;

	}

	return dev;
}