Thank you for your prompt reply！
I can create camera on "/dev/serson/", after I added yami_video_decoder.so on libcamapi_video.conf.
like this:
/etc/system/config/aoi/libcamapi_video.conf={
#libaoi configuration file

dll = "/lib/dll/mmedia/fildes_streamer.so"
    holds = 1

dll = "/lib/dll/mmedia/mp4_reader.so"
    holds = 1

dll = "/lib/dll/mmedia/mp4_writer.so"
    holds = 1

dll = "/lib/dll/mmedia/queue_filter.so"
    holds = 1

dll = "/lib/dll/mmedia/ucv_reader.so"
    holds = 1

dll = "/lib/dll/mmedia/ucv_writer.so"
    holds = 1

dll = "/lib/dll/mmedia/yami_video_encoder.so"
    holds = 1

dll = "/lib/dll/mmedia/yami_video_decoder.so"
    holds = 1
    
}
And then execute the camera_example program. Chose the 3)Camera stream, like this:
=========================================================================
libva info: VA-API version 1.4.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/dri/i965_drv_video.so
libva info: Found init function __vaDriverInit_1_1
libva info: va_openDriver() returns 0
Select which example you want to run:
        1) Camera viewfinder
        2) Record video to a file
        3) Camera stream
        4) Multiple camera video
        5) EGL viewfinder
        6) Event example
        x) Exit the example
3
Select which of the following 1 cameras you want to use:
        1) CAMERA_UNIT_1
Enter Choice:
1
Select which of the following VF modes you want to use:
        2) CAMERA_VFMODE_VIDEO
Enter Choice:
2
Do you want to modify the viewfinder configuration (y/n)?
n
Do you want to modify image attributes (y/n)?
n
Example prints the frame rate received from the camera; select x) to exit the example
Current frame rate: 30.3
=========================================================================
Can I use the sample video capture program to capture the camera stream?
https://www.qnx.com/developers/docs/7.1/index.html#com.qnx.doc.video_capture/topic/manual/vc_sample.html
But that was not work.
My test code:
int main(void) {
	int n_pointers = 2;
	screen_buffer_t *pointers = calloc(n_pointers, sizeof(screen_buffer_t));
	// connect to screen
	screen_context_t screen_ctx;
	screen_window_t screen_win;
	printf("%s:%d\n",__FUNCTION__,__LINE__);
	screen_create_context(&screen_ctx, SCREEN_APPLICATION_CONTEXT);
	screen_create_window(&screen_win, screen_ctx);
	int usage = SCREEN_USAGE_NATIVE;
	screen_set_window_property_iv(screen_win, SCREEN_PROPERTY_USAGE, &usage);
	int nbuffers = 2;
	screen_create_window_buffers(screen_win, nbuffers);
	int flags=0;//CAPTURE_BUFFER_USAGE_RDONLY;//CAPTURE_FLAG_EXTERNAL_SOURCE
	capture_context_t context = capture_create_context( flags );
	if( !context ) {
		printf("%s:%d,Handle errors:capture context is null\n",__FUNCTION__,__LINE__);
	}else{
		printf("%s:%d,capture context is not null\n",__FUNCTION__,__LINE__);
	}
	// setup capture parameters
	int getRet;
	capture_set_property_i( context, CAPTURE_PROPERTY_DEVICE, 0 );
	const char *info = NULL;
	capture_get_property_p( context, CAPTURE_PROPERTY_DEVICE_INFO, &info );
	printf("%s:%d,device-info = '%s'\n",__FUNCTION__,__LINE__,info);
	int ret=0;
	// Validate device's properties
	if( !capture_is_property( context, CAPTURE_PROPERTY_BRIGHTNESS )){
		printf("%s:%d,Unable to use buffer. Driver doesn't support CAPTURE_PROPERTY_BRIGHTNESS\n",__FUNCTION__,__LINE__);
	}
	if( !capture_is_property( context, CAPTURE_PROPERTY_CONTRAST )){
			printf("%s:%d,Unable to use buffer. Driver doesn't support CAPTURE_PROPERTY_CONTRAST\n",__FUNCTION__,__LINE__);
		}
	if( !capture_is_property( context, CAPTURE_PROPERTY_SATURATION )){
			printf("%s:%d,Unable to use buffer. Driver doesn't support CAPTURE_PROPERTY_SATURATION\n",__FUNCTION__,__LINE__);
		}
	// setup capture parameters
	capture_get_property_i( context, CAPTURE_PROPERTY_NSOURCES, &getRet );
	printf("%s:%d,Number of available source inputs; available after the...