v4l2src
Opaque object.
Hierarchy
GObject ╰──GInitiallyUnowned ╰──GstObject ╰──GstElement ╰──GstBaseSrc ╰──GstPushSrc ╰──v4l2src
Factory details
Authors: – Edgard Lima
Classification: – Source/Video
Rank – primary
Plugin – libgstvideo4linux2.so
Package – GStreamer Good Plug-ins git
Pad Templates
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
Presence – always
Direction – src
Signals
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.
Parameters:
v4l2src
–
the v4l2src instance
fd
–
the file descriptor of the current device
caps
–
the caps of the format being set
udata
–
Properties
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
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
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
num-buffers
“num-buffers” gint
Number of buffers to output before sending EOS (-1 = unlimited)
Flags : Read / Write
Default value : -1
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
Named constants
V4l2device-type-flags
Members
capture
(0x00000001) – Device supports video capture
output
(0x00000002) – Device supports video playback
overlay
(0x00000004) – Device supports video overlay
vbi-capture
(0x00000010) – Device supports the VBI capture
vbi-output
(0x00000020) – Device supports the VBI output
tuner
(0x00010000) – Device has a tuner or modulator
audio
(0x00020000) – Device has audio inputs or outputs
V4l2iomode
Members
auto
(0) – GST_V4L2_IO_AUTO
rw
(1) – GST_V4L2_IO_RW
mmap
(2) – GST_V4L2_IO_MMAP
userptr
(3) – GST_V4L2_IO_USERPTR
dmabuf
(4) – GST_V4L2_IO_DMABUF
dmabuf-import
(5) – GST_V4L2_IO_DMABUF_IMPORT
V4l2_tv_norms
Members
none
(0) – none
NTSC
(45056) – NTSC
NTSC-M
(4096) – NTSC-M
NTSC-M-JP
(8192) – NTSC-M-JP
NTSC-M-KR
(32768) – NTSC-M-KR
NTSC-443
(16384) – NTSC-443
PAL
(255) – PAL
PAL-BG
(7) – PAL-BG
PAL-B
(1) – PAL-B
PAL-B1
(2) – PAL-B1
PAL-G
(4) – PAL-G
PAL-H
(8) – PAL-H
PAL-I
(16) – PAL-I
PAL-DK
(224) – PAL-DK
PAL-D
(32) – PAL-D
PAL-D1
(64) – PAL-D1
PAL-K
(128) – PAL-K
PAL-M
(256) – PAL-M
PAL-N
(512) – PAL-N
PAL-Nc
(1024) – PAL-Nc
PAL-60
(2048) – PAL-60
SECAM
(16711680) – SECAM
SECAM-B
(65536) – SECAM-B
SECAM-G
(262144) – SECAM-G
SECAM-H
(524288) – SECAM-H
SECAM-DK
(3276800) – SECAM-DK
SECAM-D
(131072) – SECAM-D
SECAM-K
(1048576) – SECAM-K
SECAM-K1
(2097152) – SECAM-K1
SECAM-L
(4194304) – SECAM-L
SECAM-Lc
(8388608) – SECAM-Lc
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