yuv420_to_nv21

#include


void convert_yuv420_to_nv21(unsigned char * dest, const unsigned char * source, int width, int height)
{
int area = height * width;
int sqarea = area >> 3;
int qarea = area >> 2;


int count = sqarea;
const unsigned short * su = (const unsigned short *) (source + area);
const unsigned short * sv = (const unsigned short *) (source + area + qarea);
unsigned int * uv = (unsigned int *)(dest + area);

/* copy y as is */
memcpy(dest, source, area);


do
{
unsigned int u = *su++;
unsigned int v = *sv++;

*uv++ = ( ( (u & 0x00FF) << 8 ) |
( (u & 0xFF00) << 16) |
( (v & 0x00FF) )      |
( (v & 0xFF00) << 8) );
} while (--count);

}

注：这种转换是小端法机器上的转换