.\"
.\" Copyright (c) 2026 Abdelkader Boudih <freebsd@seuros.com>
.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.Dd July 28, 2026
.Dt VIDEO 4
.Os
.Sh NAME
.Nm video
.Nd video capture framework
.Sh SYNOPSIS
.Cd device video
.Pp
.In sys/videoio.h
.Sh DESCRIPTION
The
.Nm
framework provides a common interface for video capture devices.
It creates
.Pa /dev/video%d
device nodes and handles buffer management, memory mapping, and
ioctl dispatch on behalf of hardware drivers.
.Pp
Userland applications access capture devices through the
.Sy Video4Linux2
.Pq V4L2
ioctl interface.
The framework translates V4L2 requests into driver callbacks,
so hardware drivers do not implement ioctls directly.
.Pp
The following V4L2 ioctls are supported:
.Bl -bullet -compact
.It
.Dv VIDIOC_QUERYCAP
.It
.Dv VIDIOC_ENUM_FMT ,
.Dv VIDIOC_G_FMT ,
.Dv VIDIOC_S_FMT ,
.Dv VIDIOC_TRY_FMT
.It
.Dv VIDIOC_ENUM_FRAMESIZES ,
.Dv VIDIOC_ENUM_FRAMEINTERVALS
.It
.Dv VIDIOC_G_PARM ,
.Dv VIDIOC_S_PARM
.It
.Dv VIDIOC_ENUMINPUT ,
.Dv VIDIOC_G_INPUT ,
.Dv VIDIOC_S_INPUT
.It
.Dv VIDIOC_QUERYCTRL ,
.Dv VIDIOC_G_CTRL ,
.Dv VIDIOC_S_CTRL
.It
.Dv VIDIOC_REQBUFS ,
.Dv VIDIOC_QUERYBUF ,
.Dv VIDIOC_QBUF ,
.Dv VIDIOC_DQBUF
.It
.Dv VIDIOC_STREAMON ,
.Dv VIDIOC_STREAMOFF
.El
.Pp
Two capture modes are supported:
.Bl -tag -width 6n
.It Cm read
Frames are obtained by calling
.Xr read 2
on the device node.
Streaming starts automatically on the first read.
.It Cm mmap
Buffers are allocated with
.Dv VIDIOC_REQBUFS ,
mapped with
.Xr mmap 2 ,
and cycled with
.Dv VIDIOC_QBUF
and
.Dv VIDIOC_DQBUF .
Streaming is started and stopped with
.Dv VIDIOC_STREAMON
and
.Dv VIDIOC_STREAMOFF .
.El
.Pp
Up to 8 buffers may be allocated per device.
Buffer memory remains valid until the last mapping is unmapped,
even if the device is closed or detached.
.Sh SEE ALSO
.Xr mmap 2 ,
.Xr read 2 ,
.Xr fwcam 4 ,
.Xr uvideo 4
.Sh HISTORY
The
.Nm
framework first appeared in
.Fx 16.0 .
.Sh AUTHORS
.An Abdelkader Boudih Aq Mt freebsd@seuros.com