qt c++将rgb32格式转化为yuv格式
时间: 2023-12-10 16:02:13 浏览: 41
将RGB32格式转换为YUV格式需要进行颜色空间的转换。常用的颜色空间转换方法有多种,其中比较常用的方法是使用ITU-R BT.601或ITU-R BT.709标准进行转换。以下是一个使用ITU-R BT.601标准将RGB32转换为YUV格式的示例代码:
```cpp
void RGB32_to_YUV420(unsigned char *src_data, unsigned char *dst_data, int width, int height)
{
unsigned char *y_plane = dst_data;
unsigned char *u_plane = dst_data + width * height;
unsigned char *v_plane = dst_data + width * height * 5 / 4;
for (int y = 0; y < height; y += 2) {
for (int x = 0; x < width; x += 2) {
unsigned char *src_pix1 = src_data + y * width * 4 + x * 4;
unsigned char *src_pix2 = src_pix1 + width * 4;
unsigned char *src_pix3 = src_pix1 + 4;
unsigned char *src_pix4 = src_pix2 + 4;
unsigned char r1 = src_pix1[2], g1 = src_pix1[1], b1 = src_pix1[0];
unsigned char r2 = src_pix2[2], g2 = src_pix2[1], b2 = src_pix2[0];
unsigned char r3 = src_pix3[2], g3 = src_pix3[1], b3 = src_pix3[0];
unsigned char r4 = src_pix4[2], g4 = src_pix4[1], b4 = src_pix4[0];
// Calculate Y1, Y2, Y3, Y4
y_plane[y * width + x] = (unsigned char)(0.299 * r1 + 0.587 * g1 + 0.114 * b1);
y_plane[y * width + x + 1] = (unsigned char)(0.299 * r2 + 0.587 * g2 + 0.114 * b2);
y_plane[(y + 1) * width + x] = (unsigned char)(0.299 * r3 + 0.587 * g3 + 0.114 * b3);
y_plane[(y + 1) * width + x + 1] = (unsigned char)(0.299 * r4 + 0.587 * g4 + 0.114 * b4);
// Calculate U and V
int u = (int)(-0.169 * r1 - 0.331 * g1 + 0.5 * b1 + 128);
int v = (int)(0.5 * r1 - 0.419 * g1 - 0.081 * b1 + 128);
u_plane[(y / 2) * (width / 2) + (x / 2)] = (unsigned char)qBound(0, u, 255);
v_plane[(y / 2) * (width / 2) + (x / 2)] = (unsigned char)qBound(0, v, 255);
}
}
}
```
在函数中,首先将dst_data分为Y、U、V三个平面,分别保存Y、U、V分量的值。然后遍历RGB32格式的像素数据,每四个像素点为一组,分别求出Y、U、V三个分量的值,并保存到对应的平面中。其中,计算Y分量的公式为:
Y = 0.299 * R + 0.587 * G + 0.114 * B
计算U和V分量的公式为:
U = -0.169 * R - 0.331 * G + 0.5 * B + 128
V = 0.5 * R - 0.419 * G - 0.081 * B + 128
最后需要注意的是,对于U和V分量的值,需要进行范围限制,确保其值在0到255之间。上述代码中使用了Qt中的qBound函数进行范围限制。
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