Learn more about v4l2 (Video 4 Linux 2)

Many people know that v4l2 can be used to collect camera images on Linux, but v4l2 has more functions. Its main function enables the program to discover devices and operate devices. It mainly uses a series of callback functions to implement these functions. For example, set the camera frequency, frame rate, video compression format, and image parameters. Of course, it can also be used for the development of other multimedia, such as audio. However, this framework can only run on a Linux operating system.

It supports multiple devices and has the following interfaces:

1. Video Capture interface: the device of this application can be a high-frequency head or camera. The initial design of v4l2 is applied to this function.

2. video output interface: a peripheral video image device that can drive a computer, such as a device that can output a TV signal format.

3. video overlay interface: The main function of this interface is to directly output the signals collected from the video capture device to the output device without going through the system CPU.

4. Video interval hidden signal interface (VBI Interface): This interface allows applications to access and transmit video signals during the invisibility period.

5. radio interface: it can be used to process audio streams received from an AM or FM high-frequency head device.