mem_transfer.c

MPEG-4编解码的实现(包括MPEG4视音频编解码)

/**************************************************************************
 *
 *	XVID MPEG-4 VIDEO CODEC
 *	8bit<->16bit transfer
 *
 *	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:
 *
 *	07.01.2002	merge functions from compensate; rename functions
 *	22.12.2001	transfer_8to8add16 limit fix
 *	07.11.2001	initial version; (c)2001 peter ross <[e-mail]>
 *
 *************************************************************************/


#include "../global.h"
#include "mem_transfer.h"

// function pointers
TRANSFER_8TO16COPY_PTR	transfer_8to16copy;
TRANSFER_16TO8COPY_PTR	transfer_16to8copy;

TRANSFER_8TO16SUB_PTR	transfer_8to16sub;
TRANSFER_16TO8ADD_PTR	transfer_16to8add;

TRANSFER8X8_COPY_PTR	transfer8x8_copy;



void transfer_8to16copy_c(int16_t * const dst,
					const uint8_t * const src,
					uint32_t stride)
{
	uint32_t i, j;

	for (j = 0; j < 8; j++) {
		for (i = 0; i < 8; i++) {
			dst[j * 8 + i] = (int16_t)src[j * stride + i];
		}
	}
}


void transfer_16to8copy_c(uint8_t * const dst,
					const int16_t * const src,
					uint32_t stride)
{
	uint32_t i, j;

	for (j = 0; j < 8; j++) {
		for (i = 0; i < 8; i++) {
			int16_t pixel = src[j * 8 + i];
			if (pixel < 0) {
				pixel = 0;
			} else if (pixel > 255) {
				pixel = 255;
			} 
			dst[j * stride + i] = (uint8_t)pixel;
		}
	}
}




/*
  perform motion compensation (and 8bit->16bit dct transfer)
*/
void transfer_8to16sub_c(int16_t * const dct,
				uint8_t * const cur,
				const uint8_t * ref,
				const uint32_t stride)
{
	uint32_t i, j;

	for (j = 0; j < 8; j++)
	{
		for (i = 0; i < 8; i++)
		{
			uint8_t c = cur[j * stride + i];
			uint8_t r = ref[j * stride + i];
			cur[j * stride + i] = r;
			dct[j * 8 + i] = (int16_t)c - (int16_t)r;
		}
	}
}


void transfer_16to8add_c(uint8_t * const dst,
					const int16_t * const src,
					uint32_t stride)
{
	uint32_t i, j;

	for (j = 0; j < 8; j++) {
		for (i = 0; i < 8; i++) {
			int16_t pixel = (int16_t)dst[j * stride + i] + src[j * 8 + i];
			if (pixel < 0) {
				pixel = 0;
			} else if (pixel > 255) {
				pixel = 255;
			} 
			dst[j * stride + i] = (uint8_t)pixel;
		}
	}
}




void transfer8x8_copy_c(uint8_t * const dst,
					const uint8_t * const src,
					const uint32_t stride)
{
	uint32_t i, j;

	for (j = 0; j < 8; j++) {
		for (i = 0; i < 8; i++) {
			dst[j * stride + i] = src[j * stride + i];
		}
	}
}