Video4Linux

{{Short description|Device drivers for real-time video capture}}

{{Infobox software

| name = Video4Linux

| title = Video4Linux

| logo =

| logo caption =

| logo_size =

| logo_alt =

| screenshot =

| caption =

| screenshot_size =

| screenshot_alt =

| collapsible =

| author =

| developer =

| released =

| discontinued =

| latest release version =

| latest release date =

| latest preview version =

| latest preview date =

| frequently updated =

| programming language = C

| operating system = Linux

| platform = Linux kernel

| size =

| language =

| language count =

| language footnote =

| genre =

| repo = {{URL|https://git.linuxtv.org/v4l-utils.git}}

| license = GNU General Public License

| website = {{URL|http://www.linuxtv.org/}}

}}

Video4Linux (V4L for short) is a collection of device drivers and an API for supporting realtime video capture on Linux systems.{{cite web |url=https://fosdem.org/2014/schedule/event/v4l_intro/ |title=An Introduction to the Video4Linux Framework: How to write a video capture driver |date=2014-02-02 |access-date=2014-02-16}} It supports USB webcams, TV tuners, CSI cameras, and related devices, standardizing their output, so programmers can easily add video support to their applications.

Video4Linux is responsible for creating V4L2 device nodes aka a device file (/dev/videoX, /dev/vbiX and /dev/radioX) and tracking data from these nodes. The device node creation is handled by V4L device drivers using the video_device struct (v4l2-dev.h) and it can either be allocated dynamically or embedded in another larger struct.

Video4Linux was named after Video for Windows (which is sometimes abbreviated "V4W"), but is not technically related to it.{{cite web |url=https://www.kernel.org/doc/Documentation/video4linux/v4l2-framework.txt |title=Overview of the V4L2 driver framework |access-date=2013-12-04 |url-status=dead |archive-url=https://web.archive.org/web/20140221165356/https://www.kernel.org/doc/Documentation/video4linux/v4l2-framework.txt |archive-date=2014-02-21 }} Overview of the V4L2 driver framework.{{cite web| url=https://events.linuxfoundation.org/images/stories/pdf/lceu2012_debski.pdfVideo4Linux2 | title=Path to a Standardized Video Codec API |archive-url=https://web.archive.org/web/20140106032317/https://events.linuxfoundation.org/images/stories/pdf/lceu2012_debski.pdf |archive-date=2014-01-06 }}

While Video4Linux is only available on Linux, there is a compatibility layer available for FreeBSD called Video4BSD. This provides a way for many programs that depend on V4L to also compile and run on the FreeBSD operating system.