C语言实现YUV420图像90度旋转

以下是用C语言实现YUV420图像旋转90度的示例代码：

#include <stdio.h>
#include <stdlib.h>

void rotate_yuv420(unsigned char *src, unsigned char *dst, int width, int height)
{
    int i, j, k;
    int y, u, v;
    int src_idx, dst_idx;
    unsigned char *src_y = src;
    unsigned char *src_u = src + width * height;
    unsigned char *src_v = src + width * height + width * height / 4;
    unsigned char *dst_y = dst;
    unsigned char *dst_u = dst + width * height;
    unsigned char *dst_v = dst + width * height + width * height / 4;

    // rotate Y
    for (i = 0; i < width; i++) {
        for (j = 0; j < height; j++) {
            src_idx = j * width + i;
            dst_idx = (width - i - 1) * height + j;
            *(dst_y + dst_idx) = *(src_y + src_idx);
        }
    }

    // rotate U and V
    for (k = 0; k < 2; k++) {
        for (i = 0; i < width / 2; i++) {
            for (j = 0; j < height / 2; j++) {
                src_idx = j * width / 2 + i;
                dst_idx = (width / 2 - i - 1) * height / 2 + j;
                if (k == 0) {
                    *(dst_u + dst_idx) = *(src_u + src_idx);
                } else {
                    *(dst_v + dst_idx) = *(src_v + src_idx);
                }
            }
        }
    }
}

int main()
{
    int width = 640;
    int height = 480;
    int size = width * height * 3 / 2;
    unsigned char *src = (unsigned char *)malloc(size);
    unsigned char *dst = (unsigned char *)malloc(size);

    // fill src with some random data
    for (int i = 0; i < size; i++) {
        *(src + i) = i % 255;
    }

    // rotate src and save to dst
    rotate_yuv420(src, dst, width, height);

    // print some data for verification
    printf("src[0] = %d, dst[%d] = %d\n", *(src), width * height * 5 / 4, *(dst + width * height * 5 / 4));
    printf("src[%d] = %d, dst[%d] = %d\n", width * height - 1, *(src + width * height - 1), width * height / 2, *(dst + width * height / 2));
    printf("src[%d] = %d, dst[%d] = %d\n", width * height + width * height / 4 - 1, *(src + width * height + width * height / 4 - 1), width * height + width * height / 4, *(dst + width * height + width * height / 4));

    free(src);
    free(dst);

    return 0;
}

此代码假设输入的图像为YUV420格式，其中Y分量占据前width * height个字节，U分量占据接下来的width * height / 4个字节，V分量占据接下来的width * height / 4个字节。输出的图像也是YUV420格式。该函数会将输入图像顺时针旋转90度，然后保存到输出图像中。