failed to open camera.... about tensorrt_demos

[jkjung-avt]

This depends on whether gstreamer's "v4l2src" is able to handle the camera device you are using. In other words, it's a compatibility issue between the camera and the gstreamer element. When you do "cv2.VideoCapture(0)", it's leveraging opencv's internal mechanism (probably "libv4l") to handle the camera instead. That's OK too.

I will keep my implementations since I'd like to be able to set different image resolutions, e.g. 1920x1080 or 1280x720, using the gstreamer pipeline.

[gzz1529657064]

@jkjung-avt Is there a way to solve this compatibility problem? I want to use gstream.

[jkjung-avt]

Check out 'v4l2src' documentation, and try to find a gstreamer pipeline which works for your webcam. If you manage to do that, then you could modify the 'open_cam_usb()' function accordingly.

https://gstreamer.freedesktop.org/documentation/video4linux2/v4l2src.html?gi-language=c

Using 'v4l2-ctl' to check all color/resolution formats your webcam supports would also help.

https://superuser.com/questions/639738/how-can-i-list-the-available-video-modes-for-a-usb-webcam-in-linux

[zychen2016]

could use MIPI CSI camera？Like Raspberry Pi Camera v2 in Jetson nano

[jkjung-avt]

Yes, please refer to this post on my blog.

http://disq.us/p/22rtcid

[Tetsujinfr]

Great repo, thanks!
for those who want to use with a ZED camera (like me):

1. install the gstreamer plugin for the ZED
2. in the file /tensorrt_demos/utils/camera.py replace:

gst_str = ('v4l2src device=/dev/video{} ! video/x-raw, width=(int){}, height=(int){} ! videoconvert ! appsink').format(dev, width, height)
with:
gst_str = ('zedsrc stream-type=1 camera-resolution=3 camera-fps=100 ! autovideoconvert ! appsink').format(dev, width, height)

you can tweak the zedsrc source with the parameters mentioned on the zed gstreamer plugin repo readme (e.g. camera-resolution = 0, 1, 2, 3 for resp. 2K, HD, 720p, WGA)

Then execute the demo like with any USB cam, e.g. under /tensorrt_demos/:
python3 trt_yolo.py --usb 0 -m yolov4-416

Hope this will help someone. ciao

[jkjung-avt]

@Tetsujinfr Thanks for sharing this (use of ZED camera).