/************************************************************************** *                                                                        * * This code is developed by Adam Li.  This software 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 (including Project Mayo), will have no liability for use of  * * this software or modifications or derivatives thereof.                 * *                                                                        * * Project Mayo gives users of the Codec a license to this software       * * module or modifications thereof for use in hardware or software        * * products claiming conformance to the MPEG-4 Video Standard as          * * described in the Open DivX license.                                    * *                                                                        * * The complete Open DivX license can be found at                         * * http://www.projectmayo.com/opendivx/license.php .                      * *                                                                        * **************************************************************************//************************************************************************** * *  rgb2yuv.c, 24-bit RGB bitmap to YUV converter * *  Copyright (C) 2001  Project Mayo * *  Adam Li * *  DivX Advance Research Center <darc@projectmayo.com> * **************************************************************************//* This file contains RGB to YUV transformation functions.                */#include "stdlib.h"#include "rgb2yuv.h"static float RGBYUV02990[256], RGBYUV05870[256], RGBYUV01140[256];static float RGBYUV01684[256], RGBYUV03316[256];static float RGBYUV04187[256], RGBYUV00813[256];void InitLookupTable();/************************************************************************ * *  int RGB2YUV (int x_dim, int y_dim, void *bmp, YUV *yuv) * *	Purpose :	It takes a 24-bit RGB bitmap and convert it into *				YUV (4:2:0) format * *  Input :		x_dim	the x dimension of the bitmap *				y_dim	the y dimension of the bitmap *				bmp		pointer to the buffer of the bitmap *				yuv		pointer to the YUV structure * *  Output :	0		OK *				1		wrong dimension *				2		memory allocation error * *	Side Effect : *				None * *	Date :		09/28/2000 * *  Contacts: * *  Adam Li * *  DivX Advance Research Center <darc@projectmayo.com> * ************************************************************************/int RGB2YUV (int x_dim, int y_dim, void *bmp, void *y_out, void *u_out, void *v_out, int flip){	static int init_done = 0;	long i, j, size;	unsigned char *r, *g, *b;	unsigned char *y, *u, *v;	unsigned char *pu1, *pu2, *pv1, *pv2, *psu, *psv;	unsigned char *y_buffer, *u_buffer, *v_buffer;	unsigned char *sub_u_buf, *sub_v_buf;	if (init_done == 0)	{		InitLookupTable();		init_done = 1;	}	// check to see if x_dim and y_dim are divisible by 2	if ((x_dim % 2) || (y_dim % 2)) return 1;	size = x_dim * y_dim;	// allocate memory	y_buffer = (unsigned char *)y_out;	sub_u_buf = (unsigned char *)u_out;	sub_v_buf = (unsigned char *)v_out;	u_buffer = (unsigned char *)malloc(size * sizeof(unsigned char));	v_buffer = (unsigned char *)malloc(size * sizeof(unsigned char));	if (!(u_buffer && v_buffer))	{		if (u_buffer) free(u_buffer);		if (v_buffer) free(v_buffer);		return 2;	}	b = (unsigned char *)bmp;	y = y_buffer;	u = u_buffer;	v = v_buffer;	// convert RGB to YUV	if (!flip) {		for (j = 0; j < y_dim; j ++)		{			y = y_buffer + (y_dim - j - 1) * x_dim;			u = u_buffer + (y_dim - j - 1) * x_dim;			v = v_buffer + (y_dim - j - 1) * x_dim;			for (i = 0; i < x_dim; i ++) {				g = b + 1;				r = b + 2;				*y = (unsigned char)(  RGBYUV02990[*r] + RGBYUV05870[*g] + RGBYUV01140[*b]);				*u = (unsigned char)(- RGBYUV01684[*r] - RGBYUV03316[*g] + (*b)/2          + 128);				*v = (unsigned char)(  (*r)/2          - RGBYUV04187[*g] - RGBYUV00813[*b] + 128);				b += 3;				y ++;				u ++;				v ++;			}		}	} else {		for (i = 0; i < size; i++)		{			g = b + 1;			r = b + 2;			*y = (unsigned char)(  RGBYUV02990[*r] + RGBYUV05870[*g] + RGBYUV01140[*b]);			*u = (unsigned char)(- RGBYUV01684[*r] - RGBYUV03316[*g] + (*b)/2          + 128);			*v = (unsigned char)(  (*r)/2          - RGBYUV04187[*g] - RGBYUV00813[*b] + 128);			b += 3;			y ++;			u ++;			v ++;		}	}	// subsample UV	for (j = 0; j < y_dim/2; j ++)	{		psu = sub_u_buf + j * x_dim / 2;		psv = sub_v_buf + j * x_dim / 2;		pu1 = u_buffer + 2 * j * x_dim;		pu2 = u_buffer + (2 * j + 1) * x_dim;		pv1 = v_buffer + 2 * j * x_dim;		pv2 = v_buffer + (2 * j + 1) * x_dim;		for (i = 0; i < x_dim/2; i ++)		{			*psu = (*pu1 + *(pu1+1) + *pu2 + *(pu2+1)) / 4;			*psv = (*pv1 + *(pv1+1) + *pv2 + *(pv2+1)) / 4;			psu ++;			psv ++;			pu1 += 2;			pu2 += 2;			pv1 += 2;			pv2 += 2;		}	}	free(u_buffer);	free(v_buffer);	return 0;}void InitLookupTable(){	int i;	for (i = 0; i < 256; i++) RGBYUV02990[i] = (float)0.2990 * i;	for (i = 0; i < 256; i++) RGBYUV05870[i] = (float)0.5870 * i;	for (i = 0; i < 256; i++) RGBYUV01140[i] = (float)0.1140 * i;	for (i = 0; i < 256; i++) RGBYUV01684[i] = (float)0.1684 * i;	for (i = 0; i < 256; i++) RGBYUV03316[i] = (float)0.3316 * i;	for (i = 0; i < 256; i++) RGBYUV04187[i] = (float)0.4187 * i;	for (i = 0; i < 256; i++) RGBYUV00813[i] = (float)0.0813 * i;}