copy from xvid colorspace.c
you can get xvid source code from www.xvid.org
/* yuv -> rgb def's */
#define RGB_Y_OUT 1.164
#define B_U_OUT 2.018
#define Y_ADD_OUT 16
#define G_U_OUT 0.391
#define G_V_OUT 0.813
#define U_ADD_OUT 128
#define R_V_OUT 1.596
#define V_ADD_OUT 128
#define SCALEBITS_OUT 13
#define FIX_OUT(x) ((uint16_t) ((x) * (1L<<SCALEBITS_OUT) + 0.5))
/* initialize rgb lookup tables */
void
colorspace_init(void)
{
int32_t i;
for (i = 0; i < 256; i++) {
RGB_Y_tab[i] = FIX_OUT(RGB_Y_OUT) * (i - Y_ADD_OUT);
B_U_tab[i] = FIX_OUT(B_U_OUT) * (i - U_ADD_OUT);
G_U_tab[i] = FIX_OUT(G_U_OUT) * (i - U_ADD_OUT);
G_V_tab[i] = FIX_OUT(G_V_OUT) * (i - V_ADD_OUT);
R_V_tab[i] = FIX_OUT(R_V_OUT) * (i - V_ADD_OUT);
}
}
/* yuv 4:2:0 planar -> rgb555 + very simple error diffusion
*/
#define MK_RGB555(R,G,B) ((MAX(0,MIN(255, R)) << 7) & 0x7c00) | \
((MAX(0,MIN(255, G)) << 2) & 0x03e0) | \
((MAX(0,MIN(255, B)) >> 3) & 0x001f)
void
yv12_to_rgb24_c(uint8_t * dst,
int dst_stride,
uint8_t * y_src,
uint8_t * u_src,
uint8_t * v_src,
int y_stride,
int uv_stride,
int width,
int height)
{
const uint32_t dst_dif = 6 * dst_stride - 3 * width;
int32_t y_dif = 2 * y_stride - width;
uint8_t *dst2 = dst + 3 * dst_stride;
uint8_t *y_src2 = y_src + y_stride;
uint32_t x, y;
if (height < 0) { /* flip image? */
height = -height;
y_src += (height - 1) * y_stride;
y_src2 = y_src - y_stride;
u_src += (height / 2 - 1) * uv_stride;
v_src += (height / 2 - 1) * uv_stride;
y_dif = -width - 2 * y_stride;
uv_stride = -uv_stride;
}
for (y = height / 2; y; y--) {
/* process one 2x2 block per iteration */
for (x = 0; x < (uint32_t) width / 2; x++) {
int u, v;
int b_u, g_uv, r_v, rgb_y;
int r, g, b;
u = u_src[x];
v = v_src[x];
b_u = B_U_tab[u];
g_uv = G_U_tab[u] + G_V_tab[v];
r_v = R_V_tab[v];
rgb_y = RGB_Y_tab[*y_src];
b = (rgb_y + b_u) >> SCALEBITS_OUT;
g = (rgb_y - g_uv) >> SCALEBITS_OUT;
r = (rgb_y + r_v) >> SCALEBITS_OUT;
dst[0] = MAX(0, MIN(255, b));
dst[1] = MAX(0, MIN(255, g));
dst[2] = MAX(0, MIN(255, r));
y_src++;
rgb_y = RGB_Y_tab[*y_src];
b = (rgb_y + b_u) >> SCALEBITS_OUT;
g = (rgb_y - g_uv) >> SCALEBITS_OUT;
r = (rgb_y + r_v) >> SCALEBITS_OUT;
dst[3] = MAX(0, MIN(255, b));
dst[4] = MAX(0, MIN(255, g));
dst[5] = MAX(0, MIN(255, r));
y_src++;
rgb_y = RGB_Y_tab[*y_src2];
b = (rgb_y + b_u) >> SCALEBITS_OUT;
g = (rgb_y - g_uv) >> SCALEBITS_OUT;
r = (rgb_y + r_v) >> SCALEBITS_OUT;
dst2[0] = MAX(0, MIN(255, b));
dst2[1] = MAX(0, MIN(255, g));
dst2[2] = MAX(0, MIN(255, r));
y_src2++;
rgb_y = RGB_Y_tab[*y_src2];
b = (rgb_y + b_u) >> SCALEBITS_OUT;
g = (rgb_y - g_uv) >> SCALEBITS_OUT;
r = (rgb_y + r_v) >> SCALEBITS_OUT;
dst2[3] = MAX(0, MIN(255, b));
dst2[4] = MAX(0, MIN(255, g));
dst2[5] = MAX(0, MIN(255, r));
y_src2++;
dst += 6;
dst2 += 6;
}
dst += dst_dif;
dst2 += dst_dif;
y_src += y_dif;
y_src2 += y_dif;
u_src += uv_stride;
v_src += uv_stride;
}
}
>
> Hi.
> I have a Logitech webcam, and it only supports the YUV420P palette.
> I want to display the picture grabbed from the webcam in my widget.
> So, anybody can supply me source code to do the convert.
> Maybe it's only a function with several lines' source code, Thanks anyway.
>
> -Gang Sun.
>
>
> --
> video4linux-list mailing list
> Unsubscribe mailto:video4linux-list-request@xxxxxxxxxx?subject=unsubscribe
> https://www.redhat.com/mailman/listinfo/video4linux-list
>
>
>
>
________________________________________________
Message sent using UebiMiau 2.7.2
