v4l2src

Hierarchy

GObject
    ╰──GInitiallyUnowned
        ╰──GstObject
            ╰──GstElement
                ╰──GstBaseSrc
                    ╰──GstPushSrc
                        ╰──v4l2src

Implemented interfaces

GstURIHandler
GstTuner
GstColorBalance
GstVideoOrientation

Factory details

src

image/jpeg:
         parsed: true
video/mpeg:
    mpegversion: 4
   systemstream: false
video/mpeg:
    mpegversion: { (int)1, (int)2 }
video/mpegts:
   systemstream: true
video/x-bayer:
         format: { bggr, gbrg, grbg, rggb, bggr10le, gbrg10le, grbg10le, rggb10le, bggr12le, gbrg12le, grbg12le, rggb12le, bggr14le, gbrg14le, grbg14le, rggb14le, bggr16le, gbrg16le, grbg16le, rggb16le }
          width: [ 1, 32768 ]
         height: [ 1, 32768 ]
      framerate: [ 0/1, 2147483647/1 ]
video/x-dv:
   systemstream: true
video/x-fwht:
video/x-h263:
        variant: itu
video/x-h264:
  stream-format: { (string)byte-stream, (string)avc }
      alignment: au
video/x-h265:
  stream-format: byte-stream
      alignment: au
video/x-pwc1:
          width: [ 1, 32768 ]
         height: [ 1, 32768 ]
      framerate: [ 0/1, 2147483647/1 ]
video/x-pwc2:
          width: [ 1, 32768 ]
         height: [ 1, 32768 ]
      framerate: [ 0/1, 2147483647/1 ]
video/x-raw:
         format: { RGB15, RGB16, BGR, RGB, ABGR, xBGR, RGBA, RGBx, BGR15, GRAY8, GRAY16_LE, GRAY16_BE, YVU9, YUY2, YVYU, UYVY, Y41B, YUV9, NV12_64Z32, NV12_8L128, NV12_10BE_8L128, NV24, NV12_16L32S, NV61, NV16, NV21, NV12, I420, Y42B, YV12, ARGB, xRGB, BGRA, BGRx }
          width: [ 1, 32768 ]
         height: [ 1, 32768 ]
      framerate: [ 0/1, 2147483647/1 ]
video/x-sonix:
          width: [ 1, 32768 ]
         height: [ 1, 32768 ]
      framerate: [ 0/1, 2147483647/1 ]
video/x-vp8:
video/x-vp9:
video/x-wmv:
     wmvversion: 3
         format: WVC1

video/x-raw(format:Interlaced):
         format: { RGB15, RGB16, BGR, RGB, ABGR, xBGR, RGBA, RGBx, BGR15, GRAY8, GRAY16_LE, GRAY16_BE, YVU9, YUY2, YVYU, UYVY, Y41B, YUV9, NV12_64Z32, NV12_8L128, NV12_10BE_8L128, NV24, NV12_16L32S, NV61, NV16, NV21, NV12, I420, Y42B, YV12, ARGB, xRGB, BGRA, BGRx }
          width: [ 1, 32768 ]
         height: [ 1, 32768 ]
      framerate: [ 0/1, 2147483647/1 ]
 interlace-mode: alternate

prepare-format

prepare_format_callback (GstElement * v4l2src,
                         gint fd,
                         GstCaps * caps,
                         gpointer udata)

def prepare_format_callback (v4l2src, fd, caps, udata):
    #python callback for the 'prepare-format' signal

function prepare_format_callback(v4l2src: GstElement * v4l2src, fd: gint fd, caps: GstCaps * caps, udata: gpointer udata): {
    // javascript callback for the 'prepare-format' signal
}

This signal gets emitted before calling the v4l2 VIDIOC_S_FMT ioctl (set format). This allows for any custom configuration of the device to happen prior to the format being set. This is mostly useful for UVC H264 encoding cameras which need the H264 Probe & Commit to happen prior to the normal Probe & Commit.

Flags: Run Last

brightness

“brightness” gint

Picture brightness, or more precisely, the black level

Flags : Read / Write

Default value : 0

contrast

“contrast” gint

Picture contrast or luma gain

Flags : Read / Write

Default value : 0

crop-bottom

“crop-bottom” guint

Number of pixels to crop from the bottom edge of captured video stream

Flags : Read / Write

Default value : 0

Since : 1.22

crop-bounds

“crop-bounds” GstValueArray *

Crop bounding region. All crop regions must lie within this region. The bounds are represented as a four element array, that descibes the [x, y, width, height] of the area.

The size and position of the crop bounds will only be known, once the v4l2 device is opened and the input source selected. Applications can connect to the "notify::crop-bounds" signal to be notified when the bounding region is updated, and set an appropriate crop region.

Flags : Read

Since : 1.22

crop-left

“crop-left” guint

Number of pixels to crop from the left edge of captured video stream

Flags : Read / Write

Default value : 0

Since : 1.22

crop-right

“crop-right” guint

Number of pixels to crop from the right edge of captured video stream

Flags : Read / Write

Default value : 0

Since : 1.22

crop-top

“crop-top” guint

Number of pixels to crop from the top edge of captured video stream

Flags : Read / Write

Default value : 0

Since : 1.22

device

“device” gchararray

Device location

Flags : Read / Write

Default value : /dev/video0

device-fd

“device-fd” gint

File descriptor of the device

Flags : Read

Default value : -1

device-name

“device-name” gchararray

Name of the device

Flags : Read

Default value : NULL

extra-controls

“extra-controls” GstStructure *

Additional v4l2 controls for the device. The controls are identified by the control name (lowercase with '_' for any non-alphanumeric characters).

Flags : Read / Write

Since : 1.2

flags

“flags” GstV4l2DeviceTypeFlags *

Device type flags

Flags : Read

Default value : (none)

force-aspect-ratio

“force-aspect-ratio” gboolean

When enabled, the pixel aspect ratio queried from the device or set with the pixel-aspect-ratio property will be enforced.

Flags : Read / Write

Default value : true

Since : 1.2

hue

“hue” gint

Hue or color balance

Flags : Read / Write

Default value : 0

io-mode

“io-mode” GstV4l2IOMode *

IO Mode

Flags : Read / Write

Default value : auto (0)

norm

“norm” V4L2_TV_norms *

TV norm

Flags : Read / Write

Default value : none (0)

pixel-aspect-ratio

“pixel-aspect-ratio” gchararray

The pixel aspect ratio of the device. This overwrites the pixel aspect ratio queried from the device.

Flags : Read / Write

Default value : NULL

Since : 1.2

saturation

“saturation” gint

Picture color saturation or chroma gain

Flags : Read / Write

Default value : 0

GstV4l2DeviceTypeFlags

GstV4l2IOMode

V4L2_TV_norms