opencv/android/android-jni/jni/yuv420sp2rgb.c

81 lines
1.8 KiB
C

#include <string.h>
#include <jni.h>
#include <yuv420sp2rgb.h>
/*
YUV 4:2:0 image with a plane of 8 bit Y samples followed by an interleaved
U/V plane containing 8 bit 2x2 subsampled chroma samples.
except the interleave order of U and V is reversed.
H V
Y Sample Period 1 1
U (Cb) Sample Period 2 2
V (Cr) Sample Period 2 2
*/
/*
size of a char:
find . -name limits.h -exec grep CHAR_BIT {} \;
*/
#ifndef max
#define max(a,b) ({typeof(a) _a = (a); typeof(b) _b = (b); _a > _b ? _a : _b; })
#define min(a,b) ({typeof(a) _a = (a); typeof(b) _b = (b); _a < _b ? _a : _b; })
#endif
const int bytes_per_pixel = 2;
void color_convert_common(const unsigned char *pY, const unsigned char *pUV, int width, int height, unsigned char *buffer, int grey)
{
int i, j;
int nR, nG, nB;
int nY, nU, nV;
unsigned char *out = buffer;
int offset = 0;
if (grey)
{
memcpy(out,pY,width*height*sizeof(unsigned char));
}
else
// YUV 4:2:0
for (i = 0; i < height; i++)
{
for (j = 0; j < width; j++)
{
nY = *(pY + i * width + j);
nV = *(pUV + (i / 2) * width + bytes_per_pixel * (j / 2));
nU = *(pUV + (i / 2) * width + bytes_per_pixel * (j / 2) + 1);
// Yuv Convert
nY -= 16;
nU -= 128;
nV -= 128;
if (nY < 0)
nY = 0;
nB = (int)(1192 * nY + 2066 * nU);
nG = (int)(1192 * nY - 833 * nV - 400 * nU);
nR = (int)(1192 * nY + 1634 * nV);
nR = min(262143, max(0, nR));
nG = min(262143, max(0, nG));
nB = min(262143, max(0, nB));
nR >>= 10;
nR &= 0xff;
nG >>= 10;
nG &= 0xff;
nB >>= 10;
nB &= 0xff;
out[offset++] = (unsigned char)nR;
out[offset++] = (unsigned char)nG;
out[offset++] = (unsigned char)nB;
}
}
}