opencv: OpenCV does not work with new Raspberry Pi MIPI camera software stack

openCv python version 4.5.5. Camera module waveshare OV9281-110 I am working with raspberry-pi model 4-B with latest bullseye OS.

I am able to capture image using libcamera-still -o test.png command but when I try to read an image with opencv it returns None. The output for cam.isOpened() is true but cam.grab() and cam.read() return false and (false,None) respectively.

Code:

import cv2
cam_port = 0
cam = cv2.VideoCapture(cam_port)
print(cam.isOpened())
print(cam.grab())
print(cam.read())
cam.release()

Output:

True
False
(False, None)

camera info


~ $ v4l2-ctl --device /dev/video0 --all

Driver Info:
	Driver name      : unicam
	Card type        : unicam
	Bus info         : platform:fe801000.csi
	Driver version   : 5.15.56
	Capabilities     : 0xa5a00001
		Video Capture
		Metadata Capture
		Read/Write
		Streaming
		Extended Pix Format
		Device Capabilities
	Device Caps      : 0x25200001
		Video Capture
		Read/Write
		Streaming
		Extended Pix Format
Media Driver Info:
	Driver name      : unicam
	Model            : unicam
	Serial           : 
	Bus info         : platform:fe801000.csi
	Media version    : 5.15.56
	Hardware revision: 0x00000000 (0)
	Driver version   : 5.15.56
Interface Info:
	ID               : 0x03000005
	Type             : V4L Video
Entity Info:
	ID               : 0x00000003 (3)
	Name             : unicam-image
	Function         : V4L2 I/O
	Flags         : default
	Pad 0x01000004   : 0: Sink
	  Link 0x02000007: from remote pad 0x1000002 of entity 'ov9281 10-0060': Data, Enabled, Immutable
Priority: 2
Video input : 0 (unicam-image: ok)
Format Video Capture:
	Width/Height      : 640/480
	Pixel Format      : 'BGR3' (24-bit BGR 8-8-8)
	Field             : None
	Bytes per Line    : 1920
	Size Image        : 921600
	Colorspace        : sRGB
	Transfer Function : sRGB
	YCbCr/HSV Encoding: ITU-R 601
	Quantization      : Full Range
	Flags

About this issue

Original URL
State: closed
Created 2 years ago
Reactions: 1
Comments: 22 (9 by maintainers)

Most upvoted comments

Hi! I am a contributor. I have a far shot to try if you want. Depending on the capabilities of the v4l2-device it might be possible to use the FFMPEG backend for capturing and that brings the ability to specify stream details via environment variable. There is an easy test:

ffplay -f rawvideo -pixel_format bgr24 -video_size 640x480 /dev/video0

If ffplay can read your video device like that, than It should be possible to use the FFMPEG backend like this:

First change your VideoCapture to:

VideoCapture('/dev/video0', cv2.CAP_FFMPEG)

Then export OpenCV-Capture-FFMPEG options and run your command:

export OPENCV_FFMPEG_CAPTURE_OPTIONS="f;rawvideo|pixel_format;bgr24|video_size;640x480"
your_command

kallaballa on Nov 29, 2022

Not yet for now. Please switch to legacy camera mode as work around till the issue is not fixed on our side.

asmorkalov on Sep 14, 2022

I try to record a video cheese gets stuck - it’s expected behavior. Cheese uses CPU codec to encode video. It’s not capable to encode video on pi in real time. I just tried couple of my boards:

Raspberry 1b + Raspberry Pi Camera Module v2 (IMX219), OpenCV 4.6.0.66 (pip install)
Raspberry 3 + Raspberry Pi Camera Module v1 (OV5647), OpenCV 4.6.0.66 (pip install) And found out that the issue correlates with camera mode in raspi-config. Legacy v4l2 mode works well. In case I disable legacy camera mode I get the same issue like you. So it could be some issue on OpenCV side in C++ code. Let me check and I’ll return back.

asmorkalov on Sep 7, 2022

你们可以尝试使用 picamera2，请参考https://blog.csdn.net/zhangmou_9008/article/details/134047114上面的3.1 you kan try to use picamera2,please show the blog’s 3.1 :https://blog.csdn.net/zhangmou_9008/article/details/134047114

y1174804262 on Dec 27, 2023

I found the same behaviour. Trying to fix the issue to have cv::VideoCapture usable without tricks.

asmorkalov on Oct 17, 2022