v4l2-ctl | 这是从v4l2-utils里提取出来的，交叉编译到海思3518E上的 适用于其他平台。

I have a raw image that was taken with v4l2-ctl after the camera had been setup like:

I want to build Mendel Linux for the Coral Dev Board to use some changes I have made to the camera driver (ov5645_mipi_v2.c).
The problem is:
After reflashing the board, my code changes did not make it to the newly flashed board at all.

What I did:
I experimented with some changes on the camera driver (ov5645_mipi_v2.c) to introduce a new camera mode working with a higher frame rate (based on a bunch of register settings I found elsewhere, e.g. raspiraw). I followed the build instructions for the Mendel Linux distribution as stated here https://coral.googlesource.com/docs/+/refs/heads/master/GettingStarted.md and just copied my code changes into the checked out sources. I continued with the build instructions and used the m docker-dist option for the build. The build definitively did compile my changed file, as I first made a syntax mistake which lead to an aboard of the build. After the succesful build, I got the flashcard image (flashcard_arm64.img) and flashed the board. Board got reflashed and started up blank and with a new name. Although, issuing the command v4l2-ctl --list-formats-ext did not give me the results I put into the code (I changed the ov5645_mode_info within that file which should be the base for the reported available frame sizes).

I already tried the following approaches:

• running m clean and completely prune all docker images and build again
• first build with the 'all' option and then use the 'flashcard' option to build a flashcard

I think I just missed a basic step for making the build using my code changes at all, e.g. increasing some version number? or setting up a Git branch? or alike...

I want to use gstreamer (gst-launch-1.0) to stream a video signal from a camera connected to a raspberry pi (CM4) to a remote client over UDP. The gstreamer pipelines that I use always reverts to the uncompressed YUYV pixel format even after I set the format to MJPG with v4l2.

This is my pipeline:

I want to capture 1920x1080 video from my camera but I've run into two issues

1. When I initialize a VideoCapture, it changes the width/height to 640/480
2. When I try to change the width/height in cv2, the image becomes messed up

When setting 1920x1080 in cv2, the image becomes blue and has a glitchy bar at the bottom

I'm currently trying to add custom V4L2 controls to a V4L2 device after v4l2_ctrl_handler_setup is called in a Linux Kernel driver. However the control does not seem to be added (does not show up when running v4l2-ctl --list-ctrls). Below is generally the approach I am trying to take.

I am running Ubuntu 18.04 on the host and Ubuntu 20.04 inside LXC container. My goal is to run ROS2 (which requires Ubuntu 20.04) inside an LXC container, then use it to connect to two dynamixel servo motors and a USB Logitech webcam. I have also installed miniconda inside the container so that I can install OpenCV and dlib. I am also using conda virtual environment inside the container.

All the mentioned software works fine. Now I need to access the webcam with OpenCV, I use this command for testing

python -c "import cv2;print(cv2.VideoCapture(0).isOpened())"

which returns True on host but returns

So i have this logitech c920 camera 1920x1080 h264 capable and i would like to record the camera to file while at the same time copying/encoding the stream to a loopback device so the camera can be still used by other apps. here is the code i got so far:

This question is very similar to V4L2 absolute exposure setting has (almost) not effect

I have a UVC compliant camera that I am running on a Raspberry Pi CM3+ module. It appears as video0.
Using the tools/drivers v4l2-ctl, qv4l2 or guvcview the absolute exposure cannot be controlled, yet it can be controlled when using Amcap on Windows 10.

The camera has two exposure modes manual and aperature controlled. When in aperature controlled the exposure levels in the image change dynamically, however, when switched to manual mode the image becomes very dark and does not change whether at the upper or lower limit of the range which can be selected.

When running v4l2-ctl the range min is stated to be 5 and the max is 2500. Yet in windows it is between -2 and -11 and the exposure of the image changes proportionally as you would expect.

Parameter range from v4l2:

I'm using v4l2-ctl(1) to capture an image from my webcam and I'm trying to convert(1) the raw format into a png.

Here are the commands I ran.