Help: How I convert *mut *mut u8 to a Mat?

[moyang628]

this is a camera scanner sdk demo.

It get pic and info from the sdk,the pic data is a jpeg format array pointer.

I try to convert the data into a Mat. but i try to save it as a .jpg file ,it returned fail.

So，How should I to use this crate right?

the code is .

unsafe{
        let p_data: *mut *mut u8 = &mut std::mem::zeroed();
        let pst_frame_info: *mut hk_camera_sdk::MV_CODEREADER_IMAGE_OUT_INFO_EX2 =
            &mut std::mem::zeroed();
        loop {
            let ret = hk_camera_sdk::MV_CODEREADER_GetOneFrameTimeoutEx2(
                *handle.as_ref().unwrap(),
                p_data,
                pst_frame_info,
                1000,
            );
            println!("get a frame from sdk{}", ret);
            println!("the pic type is {}", pst_frame_info.as_ref().unwrap().enPixelType);
      
            let _p_data = std::mem::transmute::<*mut *mut u8,*mut c_void>(p_data);

            let mat = Mat::new_rows_cols_with_data_def(1,4096*3072, opencv::core::CV_8UC1, _p_data).unwrap();
             let retcode = imgcodecs::imwrite_def("camera.jpg",&mat ).unwrap();
             println!("{}",retcode);  //here is a false result
}