rk3568 硬解码H264 c++

根据提供的引用内容，我们可以得知rk3568支持硬解码H264。下面是一个使用C++进行rk3568硬解码H264的例子：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/videodev2.h>

#define CLEAR(x) memset(&(x), 0, sizeof(x))

struct buffer {
    void *start;
    size_t length;
};

static void errno_exit(const char *s)
{
    fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno));
    exit(EXIT_FAILURE);
}

static int xioctl(int fd, int request, void *arg)
{
    int r;

    do {
        r = ioctl(fd, request, arg);
    } while (-1 == r && EINTR == errno);

    return r;
}

static void process_image(const void *p, int size)
{
    // 处理解码后的图像数据
}

static int read_frame(int fd)
{
    struct v4l2_buffer buf;
    unsigned int i;

    CLEAR(buf);
    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buf.memory = V4L2_MEMORY_MMAP;

    if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) {
        switch (errno) {
        case EAGAIN:
            return 0;

        case EIO:
        default:
            errno_exit("VIDIOC_DQBUF");
        }
    }

    process_image(buffers[buf.index].start, buf.bytesused);

    if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
        errno_exit("VIDIOC_QBUF");

    return 1;
}

static void mainloop(int fd)
{
    unsigned int count;

    for (count = 0; count < 100; ++count) {
        for (;;) {
            fd_set fds;
            struct timeval tv;
            int r;

            FD_ZERO(&fds);
            FD_SET(fd, &fds);

            /* Timeout. */
            tv.tv_sec = 2;
            tv.tv_usec = 0;

            r = select(fd + 1, &fds, NULL, NULL, &tv);

            if (-1 == r) {
                if (EINTR == errno)
                    continue;
                errno_exit("select");
            }

            if (0 == r) {
                fprintf(stderr, "select timeout\n");
                exit(EXIT_FAILURE);
            }

            if (read_frame(fd))
                break; /* EAGAIN - continue select loop. */
        }
    }
}

static void stop_capturing(int fd)
{
    enum v4l2_buf_type type;

    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

    if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &type))
        errno_exit("VIDIOC_STREAMOFF");
}

static void start_capturing(int fd)
{
    unsigned int i;
    enum v4l2_buf_type type;

    for (i = 0; i < n_buffers; ++i) {
        struct v4l2_buffer buf;

        CLEAR(buf);

        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.memory = V4L2_MEMORY_MMAP;
        buf.index = i;

        if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
            errno_exit("VIDIOC_QBUF");
    }

    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

    if (-1 == xioctl(fd, VIDIOC_STREAMON, &type))
        errno_exit("VIDIOC_STREAMON");
}

static void uninit_device(void)
{
    unsigned int i;

    for (i = 0; i < n_buffers; ++i)
        if (-1 == munmap(buffers[i].start, buffers[i].length))
            errno_exit("munmap");

    free(buffers);
}

static void init_mmap(int fd)
{
    struct v4l2_requestbuffers req;

    CLEAR(req);

    req.count = 4;
    req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    req.memory = V4L2_MEMORY_MMAP;

    if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) {
        if (EINVAL == errno) {
            fprintf(stderr, "device does not support memory mapping\n");
            exit(EXIT_FAILURE);
        } else {
            errno_exit("VIDIOC_REQBUFS");
        }
    }

    if (req.count < 2) {
        fprintf(stderr, "Insufficient buffer memory on %s\n", dev_name);
        exit(EXIT_FAILURE);
    }

    buffers = calloc(req.count, sizeof(*buffers));

    if (!buffers) {
        fprintf(stderr, "Out of memory\n");
        exit(EXIT_FAILURE);
    }

    for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
        struct v4l2_buffer buf;

        CLEAR(buf);

        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.memory = V4L2_MEMORY_MMAP;
        buf.index = n_buffers;

        if (-1 == xioctl(fd, VIDIOC_QUERYBUF, &buf))
            errno_exit("VIDIOC_QUERYBUF");

        buffers[n_buffers].length = buf.length;
        buffers[n_buffers].start = mmap(NULL /* start anywhere */,
                buf.length,
                PROT_READ | PROT_WRITE /* required */,
                MAP_SHARED /* recommended */,
                fd, buf.m.offset);

        if (MAP_FAILED == buffers[n_buffers].start)
            errno_exit("mmap");
    }
}

static void init_device(int fd)
{
    struct v4l2_capability cap;
    struct v4l2_format fmt;
    struct v4l2_cropcap cropcap;
    struct v4l2_crop crop;
    unsigned int min;

    if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap)) {
        if (EINVAL == errno) {
            fprintf(stderr, "%s is no V4L2 device\n", dev_name);
            exit(EXIT_FAILURE);
        } else {
            errno_exit("VIDIOC_QUERYCAP");
        }
    }

    if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
        fprintf(stderr, "%s is no video capture device\n", dev_name);
        exit(EXIT_FAILURE);
    }

    if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
        fprintf(stderr, "%s does not support streaming i/o\n", dev_name);
        exit(EXIT_FAILURE);
    }

    CLEAR(cropcap);

    cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

    if (0 == xioctl(fd, VIDIOC_CROPCAP, &cropcap)) {
        crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        crop.c = cropcap.defrect; /* reset to default */

        if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop)) {
            switch (errno) {
            case EINVAL:
                /* Cropping not supported. */
                break;
            default:
                /* Errors ignored. */
                break;
            }
        }
    } else {
        /* Errors ignored. */
    }

    CLEAR(fmt);

    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    fmt.fmt.pix.width = 640;
    fmt.fmt.pix.height = 480;
    fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_H264;
    fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;

    if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt))
        errno_exit("VIDIOC_S_FMT");

    /* Note VIDIOC_S_FMT may change width and height. */

    /* Buggy driver paranoia. */
    min = fmt.fmt.pix.width * 2;
    if (fmt.fmt.pix.bytesperline < min)
        fmt.fmt.pix.bytesperline = min;
    min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
    if (fmt.fmt.pix.sizeimage < min)
        fmt.fmt.pix.sizeimage = min;

    init_mmap(fd);
}

static void close_device(int fd)
{
    if (-1 == close(fd))
        errno_exit("close");

    fd = -1;
}

static void open_device(void)
{
    struct stat st;

    if (-1 == stat(dev_name, &st)) {
        fprintf(stderr, "Cannot identify '%s': %d, %s\n",
                dev_name, errno, strerror(errno));
        exit(EXIT_FAILURE);
    }

    if (!S_ISCHR(st.st_mode)) {
        fprintf(stderr, "%s is no device\n", dev_name);
        exit(EXIT_FAILURE);
    }

    fd = open(dev_name, O_RDWR /* required */ | O_NONBLOCK, 0);

    if (-1 == fd) {
        fprintf(stderr, "Cannot open '%s': %d, %s\n",
                dev_name, errno, strerror(errno));
        exit(EXIT_FAILURE);
    }
}

int main(int argc, char **argv)
{
    dev_name = "/dev/video0";

    open_device();
    init_device(fd);
    start_capturing(fd);
    mainloop(fd);
    stop_capturing(fd);
    uninit_device();
    close_device(fd);

    return 0;
}