VIDEOIO ERROR:Unable to query number of channels

Autonomous Machines Jetson & Embedded Systems Jetson TX2
#1

I am trying to run the code on a Jetson TX2 with the on-board camera as well as trying it with a USB camera.

v4l2-ctl --list-devices

gives the following output:

vi-output, ov5693 2-0036 (platform:15700000.vi:2):
	/dev/video0

EyeToy USB camera Namtai (usb-3530000.xhci-2.2):
	/dev/video1

The following works when I execute in the terminal:

gst-launch-1.0 nvarguscamerasrc ! 'video/x-raw(memory:NVMM),width=3820, height=2464, framerate=21/1, format=NV12' ! nvvidconv flip-method=0 ! 'video/x-raw,width=960, height=616' ! nvvidconv ! nvegltransform ! nveglglessink -e

However I am running into this error, when I tried with nvarguscamerasrc inside a docker:

(darknet:80): GStreamer-CRITICAL **: 22:29:48.583: gst_element_get_state: assertion 'GST_IS_ELEMENT (element)' failed
VIDEOIO ERROR: V4L: device nvarguscamerasrc ! 'video/x-raw(memory:NVMM),width=3820, height=2464, framerate=21/1, format=NV12' ! nvvidconv flip-method=0 ! 'video/x-raw,width=960, height=616' ! nvvidconv ! nvegltransform ! nveglglessink -e: Unable to query number of channels

When I tried with v4l2src, I get the following error:

GStreamer-CRITICAL **: 16:12:31.784: gst_element_get_state: assertion ‘GST_IS_ELEMENT (element)’ failed

VIDEOIO ERROR: V4L: device v4l2src device=/dev/video0 ! video/x-raw, framerate=30/1, width=640, height=360 ! videoconvert ! appsink: Unable to query number of channels```

Any help is greatly appreciated.

#2

Hi,
Onboard camera board ov5693 is a Bayer sensor with max resolution 2592x1944. You should run

gst-launch-1.0 nvarguscamerasrc ! 'video/x-raw(memory:NVMM),width=2592, height=1944, framerate=30/1, format=NV12' ! nvvidconv ! 'video/x-raw,width=960, height=616' ! nveglglessink

/dev/video1 looks to be a USB camera. For launching it, please refer to
https://devtalk.nvidia.com/default/topic/1057681/jetson-tx1/logitech-c930e-on-jetson-tx1-very-slow-and-choppy-video/post/5363417/#5363417

#3

Thanks @daneLLL.

Regarding

gst-launch-1.0 nvarguscamerasrc ! 'video/x-raw(memory:NVMM),width=2592, height=1944, framerate=30/1, format=NV12' ! nvvidconv ! 'video/x-raw,width=960, height=616' ! nveglglessink

I ran into the same error as above:

(darknet:67): GStreamer-CRITICAL **: 20:49:25.449: gst_element_get_state: assertion 'GST_IS_ELEMENT (element)' failed

VIDEOIO ERROR: V4L: device nvarguscamerasrc ! 'video/x-raw(memory:NVMM),width=2592, height=1944, framerate=30/1, format=NV12' ! nvvidconv ! 'video/x-raw,width=960, height=616' ! nveglglessink: Unable to query number of channels

Regarding the link you provided for the USB camera(our camera is PS2 eye toy), the output for

$ v4l2-ctl -d /dev/video1 --list-formats-ext

is as follows:

ioctl: VIDIOC_ENUM_FMT
	Index       : 0
	Type        : Video Capture
	Pixel Format: 'JPEG' (compressed)
	Name        : JFIF JPEG
		Size: Discrete 320x240
		Size: Discrete 640x480

Based on the above, which pipeline do you suggest?

I tried the following commands without any luck:

gst-launch-1.0 v4l2src device=/dev/video1 ! video/x-raw,format=YUY2,width=848,height=480,framerate=30/1 ! nvvidconv ! 'video/x-raw(memory:NVMM),format=NV12' ! nvoverlaysink

gst-launch-1.0 -v v4l2src device=/dev/video1 ! image/jpeg, width=640, height=480, framerate=30/1, format=MJPG ! jpegdec ! nvvidconv ! 'video/x-raw(memory:NVMM), format=NV12' ! omxh265enc ! matroskamux ! filesink location=test_MJPG_H265enc.mkv

v4l2src device=/dev/video1 ! video/x-raw, framerate=30/1, width=640, height=360 ! videoconvert ! appsink

The above did not work as well.Thanks

#4

Hi,
For more information, does it work if you have default camera board ov5693 on devkit only? This is default hardware environment and should work by simply running

$ nvarguscamerasrc ! nvoverlaysink
#5

Thanks @DaneLLL.

The above command works on the devkit, but it throws the same error( VIDEOIO ERROR:Unable to query number of channels ) when run from within the docker container.

#6

This message is harmless. Check this post to get rid of it.

#7

Thanks! Bought a new camera ( Logitech C920) and that solved the issue. I appreciate your help!

#8