When I try to open a webcam (FLIR Boson) with OpenCV on a Jetson TX2 it gives the following error:
libv4l2: error set_fmt gave us a different result then try_fmt!
VIDEOIO ERROR: libv4l unable convert to requested pixfmt
I am using this python script:
import numpy as np
import cv2
cap = cv2.VideoCapture(0)
while(True):
# Capture frame-by-frame
ret, frame = cap.read()
# Our operations on the frame come here
# Display the resulting frame
cv2.imshow('frame',frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()
Although it does display the video it shows those errors. The reason that is relevant is I am trying to get the FLIR Boson to work with a Jetson TX2 running this program https://github.com/naisy/realtime_object_detection
I have it working with a regular webcam but with the FLIR Boson it gives
libv4l2: error set_fmt gave us a different result then try_fmt!
VIDEOIO ERROR: libv4l unable convert to requested pixfmt
VIDEOIO ERROR: V4L: Initial Capture Error: Unable to load initial memory buffers.
Segmentation fault (core dumped)
the above error and closes. In my research on the error, it seems to come up with people who use webcams that are monochrome, looking at this https://www.flir.com/support-center/oem/is-there-a-way-to-maximize-the-video-display-on-the-boson-app-for-windows-pc-to-full-screen/ I am wondering if I need to configure OpenCV or the V4L2 driver to choose the right format for the webcam to prevent the errors.
I also have a Jetson Xavier and the same object detection program works on it (it just has a different build of OpenCV and Tensorflow), so I am guessing that there is a slightly different configuration related to webcam format compatibility on that OpenCV install on the Xavier VS the TX2. I am new to all of this so forgive me if I ask for more clarification.
One last bit of info, this is out of the FLIR Boson manuel related to USB:
8.2.2 USB Boson is capable of providing digital data as a USB Video Class (UVC) compliant device. Two output options are provided. Note the options are not selected via the CCI but rather by the video capture or viewing software selected by the user. The options are:
■ Pre-AGC (16-bit): The output is linearly proportional to the flux incident on each pixel in the array; output resolution is 320x256 for the 320 configuration, 640x512 for the 640 configuration. Note that AGC settings, zoom settings, and color-encoding settings have no effect on the output signal at this tap point. This option is identified with a UVC video format 4CC code of “Y16 ” (16-bit uncompressed greyscale image)
■ Post-Colorize, YCbCrb: The output is transformed to YCbCr color space using the specified color palette (see Section 6.7). Resolution is 640x512 for both the 320 and 640 configurations. Three options are provided, identified via the UVC video format 4CC code:
• I420: 8 bit Y plane followed by 8 bit 2x2 subsampled U and V planes
• NV12: 8-bit Y plane followed by an interleaved U/V plane with 2x2 subsampling
• NV21: same as NV12 except reverse order of U and V planes
I have tried reinstalled everything several times, although it takes a few hours to reflash the TX2 and re-install open CV and Tensorflow. I have tried two different "builds" of opencv. I have tried to view the webcam with cheese and have never had a problem.
