Khadas Docs

The video node for MIPI camera is /dev/video50.

sudo apt update
sudo apt install gstreamer-aml

gst-launch-1.0 v4l2src device=/dev/video50 io-mode=mmap num-buffers=300 ! video/x-raw,format=NV12 ! amlvenc bitrate=8000 ! h264parse ! qtmux ! filesink location=test_50.mp4

sudo apt update
sudo apt install libopencv-dev python3-opencv

mipi-camera.cpp

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/core/core.hpp>
#include <iostream>
#include <string>
using
namespace  cv;
 
using
namespace  std;
 
int main(int argc, char** argv)
{
    int count=100;
    string str = argv[1];
    string res=str.substr(10);
    VideoCapture capture(stoi(res), CAP_V4L2);
    capture.set(CAP_PROP_FOURCC, VideoWriter::fourcc('U','Y','V','Y'));
    capture.set(CAP_PROP_FRAME_WIDTH, 1920);
    capture.set(CAP_PROP_FRAME_HEIGHT, 1080);
    while (count)
    {
        Mat frame;
        capture >> frame;
 
        if (frame.empty()) {
            break;
        }
        int h = frame.rows;
        int w = frame.cols;
        const char *name = "video";
        namedWindow(name, 0);
        imshow(name, frame);
        waitKey(30);
        count--;
    }
    return 0;
}

mipi-camera.cpp

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/core/core.hpp>
#include <iostream>
#include <string>
using
namespace  cv;
 
using
namespace  std;
 
int main(int argc, char** argv)
{
    int count=100;
    string str = argv[1];
    string gstformat = "NV12";
    string gstfile = "v4l2src device=" + str + " ! video/x-raw,format=" + gstformat + ",width=1920,height=1080,framerate=30/1 ! videoconvert ! appsink";
    VideoCapture capture(gstfile);
 
    while (count)
    {
        Mat frame;
        capture >> frame;
 
        if (frame.empty()) {
            break;
        }
        int h = frame.rows;
        int w = frame.cols;
        const char *name = "video";
        namedWindow(name, 0);
        imshow(name, frame);
        waitKey(30);
        count--;
    }
    return 0;
}

Compile:

gcc -o mipi mipi-camera.cpp -lopencv_imgproc -lopencv_core -lopencv_videoio -lopencv_imgcodecs -lopencv_highgui -std=c++11 -std=gnu++11 -Wall -std=c++11 -lstdc++ -I/usr/include/opencv4

Test:

./mipi /dev/video50

If you want to use the OS08A10 MIPI camera, you need to enable it in overlays, you need to add vim4n-os08a10 to fdt_overlays in /boot/dtb/amlogic/kvim4.dtb.overlay.env.

$ cat /boot/dtb/amlogic/kvim4.dtb.overlay.env 
fdt_overlays=vim4n-os08a10

And then reboot to take effect.

The video node is /dev/media0.

You can get the test source code here: https://github.com/numbqq/v4l2_media_test

Download and build the test source code:

$ git clone https://github.com/numbqq/v4l2_media_test
$ cd v4l2_media_test
$ git checkout e0482794337c01935593a91b621f9c42123cf175
$ g++ v4l2_test_raw.cpp -o v4l2_test_raw  -Wall -Wno-int-to-pointer-cast -Wno-pointer-to-int-cast -pthread -fPIE -lispaml -ldl -lmediaAPI -ltuning -lm -fPIC -D_FORTIFY_SOURCE=2 -O3
$ ls v4l2_test_raw
v4l2_test_raw

$ git clone https://github.com/numbqq/v4l2_media_test
$ cd v4l2_media_test
$ g++ v4l2_test_raw.cpp -o v4l2_test_raw  -Wall -Wno-int-to-pointer-cast -Wno-pointer-to-int-cast -pthread -fPIE -lispaml -ldl -lmediaAPI -ltuning -llens -lm -fPIC -D_FORTIFY_SOURCE=2 -O3
$ ls v4l2_test_raw
v4l2_test_raw

Test:

$ ./v4l2_test_raw -p 0 -n 10 -m /dev/media0

It will capture 10 frames to file /tmp/dst_mif_0.yuv.

Preview the file:

$ ffplay -f rawvideo -pixel_format nv21 -video_size 3840x2160 /tmp/dst_mif_0.yuv