---
name: "qv4l2"
section: "1"
platform: "linux"
package: "v4l-utils"
version: "1.32.0-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/qv4l2"
---

# qv4l2(1)

A test bench application for video4linux devices

## NAME

qv4l2 - A test bench application for video4linux devices

## SYNOPSIS

**qv4l2** \[*-R*\] \[*-h*\] \[*-d \<dev\>*\] \[*-r \<dev\>*\] \[*-V \<dev\>*\] \[*-S \<dev\>*\]

## DESCRIPTION

The qv4l2 tool is used to test video4linux capture and output devices, either video, vbi, radio or swradio. This application can also serve as a generic video/TV viewer application or as a video generator for video output devices.

However, it does not (yet) support compressed video streams other than MJPEG

## OPTIONS

- **-d**, **--device**=*\<dev\>*

  Use device \<dev\> as the video device. If \<dev\> is a number, then /dev/video\<dev\> is used.

- **-V**, **--vbi-device**=*\<dev\>*

  Use device \<dev\> as the vbi device. If \<dev\> is a number, then /dev/vbi\<dev\> is used.

- **-r**, **--radio-device**=*\<dev\>*

  Use device \<dev\> as the radio device. If \<dev\> is a number, then /dev/radio\<dev\> is used.

- **-S**, **--sdr-device**=*\<dev\>*

  Use device \<dev\> as the SDR device. If \<dev\> is a number, then /dev/swradio\<dev\> is used.

- **-R**, **--raw**

  Open device in raw mode, i.e. without using the libv4l2 wrapper functions.

- **-h**, **--help**

  Prints the help message.

## HOTKEYS

### Main Window

- *Ctrl + O*

  Open device

- *Ctrl + R*

  Open device in raw mode

- *Ctrl + W*

  Close the device

- *Ctrl + V*

  Start capture

- *Ctrl + F*

  Resize Capture Window to frame size

- *Ctrl + Q*

  Exit the application

### Capture Window

- *Ctrl + W*

  Closes the window and stops capture

- *Ctrl + F*

  Resize Capture Window to frame size

## EXIT STATUS

On success, it returns 0. Otherwise, it will return the error code.

## BUGS

Report bugs to Hans Verkuil \<hverkuil@kernel.org\>