Capture and display video from either IP CAM, USB webcam, or the Tegra X2/X1 onboard camera.

tegra-cam.py

# --------------------------------------------------------
# Camera sample code for Tegra X2/X1
#
# This program could capture and display video from
# IP CAM, USB webcam, or the Tegra onboard camera.
# Refer to the following blog post for how to set up
# and run the code:
#   https://jkjung-avt.github.io/tx2-camera-with-python/
#
# Written by JK Jung <[email protected]>
# --------------------------------------------------------


import sys
import argparse
import subprocess

import cv2


WINDOW_NAME = 'CameraDemo'


def parse_args():
    # Parse input arguments
    desc = 'Capture and display live camera video on Jetson TX2/TX1'
    parser = argparse.ArgumentParser(description=desc)
    parser.add_argument('--rtsp', dest='use_rtsp',
                        help='use IP CAM (remember to also set --uri)',
                        action='store_true')
    parser.add_argument('--uri', dest='rtsp_uri',
                        help='RTSP URI, e.g. rtsp://192.168.1.64:554',
                        default=None, type=str)
    parser.add_argument('--latency', dest='rtsp_latency',
                        help='latency in ms for RTSP [200]',
                        default=200, type=int)
    parser.add_argument('--usb', dest='use_usb',
                        help='use USB webcam (remember to also set --vid)',
                        action='store_true')
    parser.add_argument('--vid', dest='video_dev',
                        help='device # of USB webcam (/dev/video?) [1]',
                        default=1, type=int)
    parser.add_argument('--width', dest='image_width',
                        help='image width [1920]',
                        default=1920, type=int)
    parser.add_argument('--height', dest='image_height',
                        help='image height [1080]',
                        default=1080, type=int)
    args = parser.parse_args()
    return args


def open_cam_rtsp(uri, width, height, latency):
    gst_str = ('rtspsrc location={} latency={} ! '
               'rtph264depay ! h264parse ! omxh264dec ! '
               'nvvidconv ! '
               'video/x-raw, width=(int){}, height=(int){}, '
               'format=(string)BGRx ! '
               'videoconvert ! appsink').format(uri, latency, width, height)
    return cv2.VideoCapture(gst_str, cv2.CAP_GSTREAMER)


def open_cam_usb(dev, width, height):
    # We want to set width and height here, otherwise we could just do:
    #     return cv2.VideoCapture(dev)
    gst_str = ('v4l2src device=/dev/video{} ! '
               'video/x-raw, width=(int){}, height=(int){} ! '
               'videoconvert ! appsink').format(dev, width, height)
    return cv2.VideoCapture(gst_str, cv2.CAP_GSTREAMER)


def open_cam_onboard(width, height):
    gst_elements = str(subprocess.check_output('gst-inspect-1.0'))
    if 'nvcamerasrc' in gst_elements:
        # On versions of L4T prior to 28.1, add 'flip-method=2' into gst_str
        gst_str = ('nvcamerasrc ! '
                   'video/x-raw(memory:NVMM), '
                   'width=(int)2592, height=(int)1458, '
                   'format=(string)I420, framerate=(fraction)30/1 ! '
                   'nvvidconv ! '
                   'video/x-raw, width=(int){}, height=(int){}, '
                   'format=(string)BGRx ! '
                   'videoconvert ! appsink').format(width, height)
    elif 'nvarguscamerasrc' in gst_elements:
        gst_str = ('nvarguscamerasrc ! '
                   'video/x-raw(memory:NVMM), '
                   'width=(int)1920, height=(int)1080, '
                   'format=(string)NV12, framerate=(fraction)30/1 ! '
                   'nvvidconv flip-method=2 ! '
                   'video/x-raw, width=(int){}, height=(int){}, '
                   'format=(string)BGRx ! '
                   'videoconvert ! appsink').format(width, height)
    else:
        raise RuntimeError('onboard camera source not found!')
    return cv2.VideoCapture(gst_str, cv2.CAP_GSTREAMER)


def open_window(width, height):
    cv2.namedWindow(WINDOW_NAME, cv2.WINDOW_NORMAL)
    cv2.resizeWindow(WINDOW_NAME, width, height)
    cv2.moveWindow(WINDOW_NAME, 0, 0)
    cv2.setWindowTitle(WINDOW_NAME, 'Camera Demo for Jetson TX2/TX1')


def read_cam(cap):
    show_help = True
    full_scrn = False
    help_text = '"Esc" to Quit, "H" for Help, "F" to Toggle Fullscreen'
    font = cv2.FONT_HERSHEY_PLAIN
    while True:
        if cv2.getWindowProperty(WINDOW_NAME, 0) < 0:
            # Check to see if the user has closed the window
            # If yes, terminate the program
            break
        _, img = cap.read() # grab the next image frame from camera
        if show_help:
            cv2.putText(img, help_text, (11, 20), font,
                        1.0, (32, 32, 32), 4, cv2.LINE_AA)
            cv2.putText(img, help_text, (10, 20), font,
                        1.0, (240, 240, 240), 1, cv2.LINE_AA)
        cv2.imshow(WINDOW_NAME, img)
        key = cv2.waitKey(10)
        if key == 27: # ESC key: quit program
            break
        elif key == ord('H') or key == ord('h'): # toggle help message
            show_help = not show_help
        elif key == ord('F') or key == ord('f'): # toggle fullscreen
            full_scrn = not full_scrn
            if full_scrn:
                cv2.setWindowProperty(WINDOW_NAME, cv2.WND_PROP_FULLSCREEN,
                                      cv2.WINDOW_FULLSCREEN)
            else:
                cv2.setWindowProperty(WINDOW_NAME, cv2.WND_PROP_FULLSCREEN,
                                      cv2.WINDOW_NORMAL)


def main():
    args = parse_args()
    print('Called with args:')
    print(args)
    print('OpenCV version: {}'.format(cv2.__version__))

    if args.use_rtsp:
        cap = open_cam_rtsp(args.rtsp_uri,
                            args.image_width,
                            args.image_height,
                            args.rtsp_latency)
    elif args.use_usb:
        cap = open_cam_usb(args.video_dev,
                           args.image_width,
                           args.image_height)
    else: # by default, use the Jetson onboard camera
        cap = open_cam_onboard(args.image_width,
                               args.image_height)

    if not cap.isOpened():
        sys.exit('Failed to open camera!')

    open_window(args.image_width, args.image_height)
    read_cam(cap)

    cap.release()
    cv2.destroyAllWindows()


if __name__ == '__main__':
    main()

@kuzmich9023 Refer to https://gist.github.com/jkjung-avt/86b60a7723b97da19f7bfa3cb7d2690e#gistcomment-2917499.

I entered the command from the post you gave me. Where else can I fix it to make it work for me?

You can write an example. I'm just starting to understand Linux ...

Hi, Is it possible to stream onboard camera output of jetson nano to 2 virtual camera sinks? I tried doing that with: gst-launch-1.0 -v nvarguscamerasrc ! 'video/x-raw(memory:NVMM), format=NV12, width=1920, height=1080, framerate=30/1' ! nvvidconv ! 'video/x-raw, width=640, height=480, format=I420, framerate=30/1' ! videoconvert ! identity drop-allocation=1 ! 'video/x-raw, width=640, height=480, format=RGB, framerate=30/1' ! v4l2sink device=/dev/video3 v4l2sink device=/dev/video4

but it isn't working. Essentially, I want to mirror my onboard camera stream to device's web browser for which I created 2 virtual camera devices namely /dev/video3 and /dev/video4 but it only streams to a single virtual camera device (this command works in case of single sink)

in case @bhavitvyamalik (or anyone else) is still wondering how to achieve this, you need to use tee and queue:

First create the two devices: sudo modprobe v4l2loopback devices=2
gst-launch-1.0 -v nvarguscamerasrc ! 'video/x-raw(memory:NVMM), format=NV12, width=640, height=480, framerate=30/1' ! nvvidconv ! 'video/x-raw, width=640, height=480, format=I420, framerate=30/1' ! videoconvert ! identity drop-allocation=1 ! 'video/x-raw, width=640, height=480, format=RGB, framerate=30/1' ! tee name=t ! queue ! v4l2sink device=/dev/video1 t. ! queue ! v4l2sink device=/dev/video2

Thanks a lot for your tip.

@niteshgaba Please refer to:

• Tegra Camera Recorder, or
• get_video_writer() in writer.py

Do you have any idea about known issues of opencv 4.1.1 with gstreamer. If i run the image capture for 5 seconds in a thread the pipeline closes fine and if ran for a large number of seconds, it just stays and does not closes.

Sorry. It does not ring a bell for me.