v4l2src

Hierarchy

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

Factory details

src

image/jpeg:
video/mpeg:
    mpegversion: 4
   systemstream: false
video/mpeg:
    mpegversion: 2
video/mpegts:
   systemstream: true
video/x-bayer:
         format: { bggr, gbrg, grbg, rggb }
          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: { RGB16, BGR, RGB, GRAY8, GRAY16_LE, GRAY16_BE, YVU9, YV12, YUY2, YVYU, UYVY, Y42B, Y41B, YUV9, NV12_64Z32, NV24, NV61, NV16, NV21, NV12, I420, BGRA, BGRx, ARGB, xRGB, BGR15, RGB15 }
          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

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.

blocksize

“blocksize” guint

Size in bytes to read per buffer (-1 = default)

Flags : Read / Write

Default value : 4096

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

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

do-timestamp

“do-timestamp” gboolean

Apply current stream time to buffers

Flags : Read / Write

Default value : false

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

flags

“flags” V4l2device-type-flags

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

hue

“hue” gint

Hue or color balance

Flags : Read / Write

Default value : 0

io-mode

“io-mode” V4l2iomode

IO Mode

Flags : Read / Write

Default value : auto (0)

name

“name” gchararray

The name of the object

Flags : Read / Write / Construct

Default value : NULL

norm

“norm” V4l2_tv_norms

TV norm

Flags : Read / Write

Default value : none (0)

num-buffers

“num-buffers” gint

Number of buffers to output before sending EOS (-1 = unlimited)

Flags : Read / Write

Default value : -1

parent

“parent” GstObject *

The parent of the object

Flags : Read / Write

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

saturation

“saturation” gint

Picture color saturation or chroma gain

Flags : Read / Write

Default value : 0

typefind

“typefind” gboolean

Run typefind before negotiating (deprecated, non-functional)

Flags : Read / Write

Default value : false

V4l2device-type-flags

V4l2iomode

V4l2_tv_norms