How can I divide two cfg.enable_streams in D435 camera?

I wish to see two parts of a video by IntelRealsence D435 camera.

one is RGB in 640x480, another is IR(depth camera) in 1280x720.

the following code got error, maybe cfg.enable_stream can't be divided by size.

how can I divide them? Here is my code:

#include <opencv2/opencv.hpp>
#include "example.hpp"

#include <stdio.h>

using namespace std;
using namespace cv;


int main()
{
    rs2::pipeline pipe;
rs2::config cfg;

//Add desired streams to configuration
cfg.enable_stream(RS2_STREAM_COLOR, RS2_FORMAT_BGR8, 30);
//for infrared
//cfg.enable_stream(RS2_STREAM_INFRARED, 1280, 720, RS2_FORMAT_Y8, 30);
cfg.enable_stream(RS2_STREAM_DEPTH, RS2_FORMAT_Z16, 30);

pipe.start(cfg);

texture depth_image;

rs2::align align_to(RS2_STREAM_DEPTH);

rs2::decimation_filter dec;

dec.set_option(RS2_OPTION_FILTER_MAGNITUDE, 2);

rs2::disparity_transform depth2disparity;

// Define spatial filter (edge-preserving)
rs2::spatial_filter spat;

spat.set_option(RS2_OPTION_HOLES_FILL, 5);
rs2::temporal_filter temp;

rs2::disparity_transform disparity2depth(false);

rs2::frame_queue postprocessed_frames;

CvSize size = cvSize(1280, 720);

for (;;)
{
    rs2::frameset frames = pipe.wait_for_frames();
    rs2::frame color_frame = frames.get_color_frame();

    rs2::colorizer color_map;
    rs2::frame depth_frame = color_map(frames.get_depth_frame());

I will run this code to get picture Mat color(Size(640, 480), CV_8UC3, (void*)color_frame.get_data(), Mat::AUTO_STEP); const IplImage image_frame_show = new IplImage(color); namedWindow("Display color", WINDOW_AUTOSIZE); cvShowImage("Display color", image_frame_show); Mat depth_show(Size(1280, 720), CV_8UC3, (void)depth_frame.get_data(), Mat::AUTO_STEP); const IplImage *depth_frame_show = new IplImage(depth_show); namedWindow("Display depth", WINDOW_AUTOSIZE); cvShowImage("Display depth", depth_frame_show);

    waitKey(10);

}

return 0;

}