ef9f18a9e3
Add V4L2_COLORFX_SET_RGB color effects control, V4L2_CID_COLORFX_RGB for RGB color setting. with two mirror changes: - change 0xFFFFFF to 0xffffff - fix comments 2^24 to 2^24 - 1 [hverkuil: dropped spaces around + with V4L2_CID_BASE for consistency] Signed-off-by: Dillon Min <dillon.minfei@gmail.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
518 lines
17 KiB
ReStructuredText
518 lines
17 KiB
ReStructuredText
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
|
|
|
|
.. _control:
|
|
|
|
*************
|
|
User Controls
|
|
*************
|
|
|
|
Devices typically have a number of user-settable controls such as
|
|
brightness, saturation and so on, which would be presented to the user
|
|
on a graphical user interface. But, different devices will have
|
|
different controls available, and furthermore, the range of possible
|
|
values, and the default value will vary from device to device. The
|
|
control ioctls provide the information and a mechanism to create a nice
|
|
user interface for these controls that will work correctly with any
|
|
device.
|
|
|
|
All controls are accessed using an ID value. V4L2 defines several IDs
|
|
for specific purposes. Drivers can also implement their own custom
|
|
controls using ``V4L2_CID_PRIVATE_BASE`` [#f1]_ and higher values. The
|
|
pre-defined control IDs have the prefix ``V4L2_CID_``, and are listed in
|
|
:ref:`control-id`. The ID is used when querying the attributes of a
|
|
control, and when getting or setting the current value.
|
|
|
|
Generally applications should present controls to the user without
|
|
assumptions about their purpose. Each control comes with a name string
|
|
the user is supposed to understand. When the purpose is non-intuitive
|
|
the driver writer should provide a user manual, a user interface plug-in
|
|
or a driver specific panel application. Predefined IDs were introduced
|
|
to change a few controls programmatically, for example to mute a device
|
|
during a channel switch.
|
|
|
|
Drivers may enumerate different controls after switching the current
|
|
video input or output, tuner or modulator, or audio input or output.
|
|
Different in the sense of other bounds, another default and current
|
|
value, step size or other menu items. A control with a certain *custom*
|
|
ID can also change name and type.
|
|
|
|
If a control is not applicable to the current configuration of the
|
|
device (for example, it doesn't apply to the current video input)
|
|
drivers set the ``V4L2_CTRL_FLAG_INACTIVE`` flag.
|
|
|
|
Control values are stored globally, they do not change when switching
|
|
except to stay within the reported bounds. They also do not change e. g.
|
|
when the device is opened or closed, when the tuner radio frequency is
|
|
changed or generally never without application request.
|
|
|
|
V4L2 specifies an event mechanism to notify applications when controls
|
|
change value (see
|
|
:ref:`VIDIOC_SUBSCRIBE_EVENT`, event
|
|
``V4L2_EVENT_CTRL``), panel applications might want to make use of that
|
|
in order to always reflect the correct control value.
|
|
|
|
All controls use machine endianness.
|
|
|
|
|
|
.. _control-id:
|
|
|
|
Control IDs
|
|
===========
|
|
|
|
``V4L2_CID_BASE``
|
|
First predefined ID, equal to ``V4L2_CID_BRIGHTNESS``.
|
|
|
|
``V4L2_CID_USER_BASE``
|
|
Synonym of ``V4L2_CID_BASE``.
|
|
|
|
``V4L2_CID_BRIGHTNESS`` ``(integer)``
|
|
Picture brightness, or more precisely, the black level.
|
|
|
|
``V4L2_CID_CONTRAST`` ``(integer)``
|
|
Picture contrast or luma gain.
|
|
|
|
``V4L2_CID_SATURATION`` ``(integer)``
|
|
Picture color saturation or chroma gain.
|
|
|
|
``V4L2_CID_HUE`` ``(integer)``
|
|
Hue or color balance.
|
|
|
|
``V4L2_CID_AUDIO_VOLUME`` ``(integer)``
|
|
Overall audio volume. Note some drivers also provide an OSS or ALSA
|
|
mixer interface.
|
|
|
|
``V4L2_CID_AUDIO_BALANCE`` ``(integer)``
|
|
Audio stereo balance. Minimum corresponds to all the way left,
|
|
maximum to right.
|
|
|
|
``V4L2_CID_AUDIO_BASS`` ``(integer)``
|
|
Audio bass adjustment.
|
|
|
|
``V4L2_CID_AUDIO_TREBLE`` ``(integer)``
|
|
Audio treble adjustment.
|
|
|
|
``V4L2_CID_AUDIO_MUTE`` ``(boolean)``
|
|
Mute audio, i. e. set the volume to zero, however without affecting
|
|
``V4L2_CID_AUDIO_VOLUME``. Like ALSA drivers, V4L2 drivers must mute
|
|
at load time to avoid excessive noise. Actually the entire device
|
|
should be reset to a low power consumption state.
|
|
|
|
``V4L2_CID_AUDIO_LOUDNESS`` ``(boolean)``
|
|
Loudness mode (bass boost).
|
|
|
|
``V4L2_CID_BLACK_LEVEL`` ``(integer)``
|
|
Another name for brightness (not a synonym of
|
|
``V4L2_CID_BRIGHTNESS``). This control is deprecated and should not
|
|
be used in new drivers and applications.
|
|
|
|
``V4L2_CID_AUTO_WHITE_BALANCE`` ``(boolean)``
|
|
Automatic white balance (cameras).
|
|
|
|
``V4L2_CID_DO_WHITE_BALANCE`` ``(button)``
|
|
This is an action control. When set (the value is ignored), the
|
|
device will do a white balance and then hold the current setting.
|
|
Contrast this with the boolean ``V4L2_CID_AUTO_WHITE_BALANCE``,
|
|
which, when activated, keeps adjusting the white balance.
|
|
|
|
``V4L2_CID_RED_BALANCE`` ``(integer)``
|
|
Red chroma balance.
|
|
|
|
``V4L2_CID_BLUE_BALANCE`` ``(integer)``
|
|
Blue chroma balance.
|
|
|
|
``V4L2_CID_GAMMA`` ``(integer)``
|
|
Gamma adjust.
|
|
|
|
``V4L2_CID_WHITENESS`` ``(integer)``
|
|
Whiteness for grey-scale devices. This is a synonym for
|
|
``V4L2_CID_GAMMA``. This control is deprecated and should not be
|
|
used in new drivers and applications.
|
|
|
|
``V4L2_CID_EXPOSURE`` ``(integer)``
|
|
Exposure (cameras). [Unit?]
|
|
|
|
``V4L2_CID_AUTOGAIN`` ``(boolean)``
|
|
Automatic gain/exposure control.
|
|
|
|
``V4L2_CID_GAIN`` ``(integer)``
|
|
Gain control.
|
|
|
|
Primarily used to control gain on e.g. TV tuners but also on
|
|
webcams. Most devices control only digital gain with this control
|
|
but on some this could include analogue gain as well. Devices that
|
|
recognise the difference between digital and analogue gain use
|
|
controls ``V4L2_CID_DIGITAL_GAIN`` and ``V4L2_CID_ANALOGUE_GAIN``.
|
|
|
|
``V4L2_CID_HFLIP`` ``(boolean)``
|
|
Mirror the picture horizontally.
|
|
|
|
``V4L2_CID_VFLIP`` ``(boolean)``
|
|
Mirror the picture vertically.
|
|
|
|
.. _v4l2-power-line-frequency:
|
|
|
|
``V4L2_CID_POWER_LINE_FREQUENCY`` ``(enum)``
|
|
Enables a power line frequency filter to avoid flicker. Possible
|
|
values for ``enum v4l2_power_line_frequency`` are:
|
|
|
|
========================================== ==
|
|
``V4L2_CID_POWER_LINE_FREQUENCY_DISABLED`` 0
|
|
``V4L2_CID_POWER_LINE_FREQUENCY_50HZ`` 1
|
|
``V4L2_CID_POWER_LINE_FREQUENCY_60HZ`` 2
|
|
``V4L2_CID_POWER_LINE_FREQUENCY_AUTO`` 3
|
|
========================================== ==
|
|
|
|
``V4L2_CID_HUE_AUTO`` ``(boolean)``
|
|
Enables automatic hue control by the device. The effect of setting
|
|
``V4L2_CID_HUE`` while automatic hue control is enabled is
|
|
undefined, drivers should ignore such request.
|
|
|
|
``V4L2_CID_WHITE_BALANCE_TEMPERATURE`` ``(integer)``
|
|
This control specifies the white balance settings as a color
|
|
temperature in Kelvin. A driver should have a minimum of 2800
|
|
(incandescent) to 6500 (daylight). For more information about color
|
|
temperature see
|
|
`Wikipedia <http://en.wikipedia.org/wiki/Color_temperature>`__.
|
|
|
|
``V4L2_CID_SHARPNESS`` ``(integer)``
|
|
Adjusts the sharpness filters in a camera. The minimum value
|
|
disables the filters, higher values give a sharper picture.
|
|
|
|
``V4L2_CID_BACKLIGHT_COMPENSATION`` ``(integer)``
|
|
Adjusts the backlight compensation in a camera. The minimum value
|
|
disables backlight compensation.
|
|
|
|
``V4L2_CID_CHROMA_AGC`` ``(boolean)``
|
|
Chroma automatic gain control.
|
|
|
|
``V4L2_CID_CHROMA_GAIN`` ``(integer)``
|
|
Adjusts the Chroma gain control (for use when chroma AGC is
|
|
disabled).
|
|
|
|
``V4L2_CID_COLOR_KILLER`` ``(boolean)``
|
|
Enable the color killer (i. e. force a black & white image in case
|
|
of a weak video signal).
|
|
|
|
.. _v4l2-colorfx:
|
|
|
|
``V4L2_CID_COLORFX`` ``(enum)``
|
|
Selects a color effect. The following values are defined:
|
|
|
|
|
|
|
|
.. tabularcolumns:: |p{5.7cm}|p{11.8cm}|
|
|
|
|
.. flat-table::
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
:widths: 11 24
|
|
|
|
* - ``V4L2_COLORFX_NONE``
|
|
- Color effect is disabled.
|
|
* - ``V4L2_COLORFX_ANTIQUE``
|
|
- An aging (old photo) effect.
|
|
* - ``V4L2_COLORFX_ART_FREEZE``
|
|
- Frost color effect.
|
|
* - ``V4L2_COLORFX_AQUA``
|
|
- Water color, cool tone.
|
|
* - ``V4L2_COLORFX_BW``
|
|
- Black and white.
|
|
* - ``V4L2_COLORFX_EMBOSS``
|
|
- Emboss, the highlights and shadows replace light/dark boundaries
|
|
and low contrast areas are set to a gray background.
|
|
* - ``V4L2_COLORFX_GRASS_GREEN``
|
|
- Grass green.
|
|
* - ``V4L2_COLORFX_NEGATIVE``
|
|
- Negative.
|
|
* - ``V4L2_COLORFX_SEPIA``
|
|
- Sepia tone.
|
|
* - ``V4L2_COLORFX_SKETCH``
|
|
- Sketch.
|
|
* - ``V4L2_COLORFX_SKIN_WHITEN``
|
|
- Skin whiten.
|
|
* - ``V4L2_COLORFX_SKY_BLUE``
|
|
- Sky blue.
|
|
* - ``V4L2_COLORFX_SOLARIZATION``
|
|
- Solarization, the image is partially reversed in tone, only color
|
|
values above or below a certain threshold are inverted.
|
|
* - ``V4L2_COLORFX_SILHOUETTE``
|
|
- Silhouette (outline).
|
|
* - ``V4L2_COLORFX_VIVID``
|
|
- Vivid colors.
|
|
* - ``V4L2_COLORFX_SET_CBCR``
|
|
- The Cb and Cr chroma components are replaced by fixed coefficients
|
|
determined by ``V4L2_CID_COLORFX_CBCR`` control.
|
|
* - ``V4L2_COLORFX_SET_RGB``
|
|
- The RGB components are replaced by the fixed RGB components determined
|
|
by ``V4L2_CID_COLORFX_RGB`` control.
|
|
|
|
|
|
``V4L2_CID_COLORFX_RGB`` ``(integer)``
|
|
Determines the Red, Green, and Blue coefficients for
|
|
``V4L2_COLORFX_SET_RGB`` color effect.
|
|
Bits [7:0] of the supplied 32 bit value are interpreted as Blue component,
|
|
bits [15:8] as Green component, bits [23:16] as Red component, and
|
|
bits [31:24] must be zero.
|
|
|
|
``V4L2_CID_COLORFX_CBCR`` ``(integer)``
|
|
Determines the Cb and Cr coefficients for ``V4L2_COLORFX_SET_CBCR``
|
|
color effect. Bits [7:0] of the supplied 32 bit value are
|
|
interpreted as Cr component, bits [15:8] as Cb component and bits
|
|
[31:16] must be zero.
|
|
|
|
``V4L2_CID_AUTOBRIGHTNESS`` ``(boolean)``
|
|
Enable Automatic Brightness.
|
|
|
|
``V4L2_CID_ROTATE`` ``(integer)``
|
|
Rotates the image by specified angle. Common angles are 90, 270 and
|
|
180. Rotating the image to 90 and 270 will reverse the height and
|
|
width of the display window. It is necessary to set the new height
|
|
and width of the picture using the
|
|
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl according to the
|
|
rotation angle selected.
|
|
|
|
``V4L2_CID_BG_COLOR`` ``(integer)``
|
|
Sets the background color on the current output device. Background
|
|
color needs to be specified in the RGB24 format. The supplied 32 bit
|
|
value is interpreted as bits 0-7 Red color information, bits 8-15
|
|
Green color information, bits 16-23 Blue color information and bits
|
|
24-31 must be zero.
|
|
|
|
``V4L2_CID_ILLUMINATORS_1 V4L2_CID_ILLUMINATORS_2`` ``(boolean)``
|
|
Switch on or off the illuminator 1 or 2 of the device (usually a
|
|
microscope).
|
|
|
|
``V4L2_CID_MIN_BUFFERS_FOR_CAPTURE`` ``(integer)``
|
|
This is a read-only control that can be read by the application and
|
|
used as a hint to determine the number of CAPTURE buffers to pass to
|
|
REQBUFS. The value is the minimum number of CAPTURE buffers that is
|
|
necessary for hardware to work.
|
|
|
|
``V4L2_CID_MIN_BUFFERS_FOR_OUTPUT`` ``(integer)``
|
|
This is a read-only control that can be read by the application and
|
|
used as a hint to determine the number of OUTPUT buffers to pass to
|
|
REQBUFS. The value is the minimum number of OUTPUT buffers that is
|
|
necessary for hardware to work.
|
|
|
|
.. _v4l2-alpha-component:
|
|
|
|
``V4L2_CID_ALPHA_COMPONENT`` ``(integer)``
|
|
Sets the alpha color component. When a capture device (or capture
|
|
queue of a mem-to-mem device) produces a frame format that includes
|
|
an alpha component (e.g.
|
|
:ref:`packed RGB image formats <pixfmt-rgb>`) and the alpha value
|
|
is not defined by the device or the mem-to-mem input data this
|
|
control lets you select the alpha component value of all pixels.
|
|
When an output device (or output queue of a mem-to-mem device)
|
|
consumes a frame format that doesn't include an alpha component and
|
|
the device supports alpha channel processing this control lets you
|
|
set the alpha component value of all pixels for further processing
|
|
in the device.
|
|
|
|
``V4L2_CID_LASTP1``
|
|
End of the predefined control IDs (currently
|
|
``V4L2_CID_ALPHA_COMPONENT`` + 1).
|
|
|
|
``V4L2_CID_PRIVATE_BASE``
|
|
ID of the first custom (driver specific) control. Applications
|
|
depending on particular custom controls should check the driver name
|
|
and version, see :ref:`querycap`.
|
|
|
|
Applications can enumerate the available controls with the
|
|
:ref:`VIDIOC_QUERYCTRL` and
|
|
:ref:`VIDIOC_QUERYMENU <VIDIOC_QUERYCTRL>` ioctls, get and set a
|
|
control value with the :ref:`VIDIOC_G_CTRL <VIDIOC_G_CTRL>` and
|
|
:ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>` ioctls. Drivers must implement
|
|
``VIDIOC_QUERYCTRL``, ``VIDIOC_G_CTRL`` and ``VIDIOC_S_CTRL`` when the
|
|
device has one or more controls, ``VIDIOC_QUERYMENU`` when it has one or
|
|
more menu type controls.
|
|
|
|
|
|
.. _enum_all_controls:
|
|
|
|
Example: Enumerating all controls
|
|
=================================
|
|
|
|
.. code-block:: c
|
|
|
|
struct v4l2_queryctrl queryctrl;
|
|
struct v4l2_querymenu querymenu;
|
|
|
|
static void enumerate_menu(__u32 id)
|
|
{
|
|
printf(" Menu items:\\n");
|
|
|
|
memset(&querymenu, 0, sizeof(querymenu));
|
|
querymenu.id = id;
|
|
|
|
for (querymenu.index = queryctrl.minimum;
|
|
querymenu.index <= queryctrl.maximum;
|
|
querymenu.index++) {
|
|
if (0 == ioctl(fd, VIDIOC_QUERYMENU, &querymenu)) {
|
|
printf(" %s\\n", querymenu.name);
|
|
}
|
|
}
|
|
}
|
|
|
|
memset(&queryctrl, 0, sizeof(queryctrl));
|
|
|
|
queryctrl.id = V4L2_CTRL_FLAG_NEXT_CTRL;
|
|
while (0 == ioctl(fd, VIDIOC_QUERYCTRL, &queryctrl)) {
|
|
if (!(queryctrl.flags & V4L2_CTRL_FLAG_DISABLED)) {
|
|
printf("Control %s\\n", queryctrl.name);
|
|
|
|
if (queryctrl.type == V4L2_CTRL_TYPE_MENU)
|
|
enumerate_menu(queryctrl.id);
|
|
}
|
|
|
|
queryctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL;
|
|
}
|
|
if (errno != EINVAL) {
|
|
perror("VIDIOC_QUERYCTRL");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
Example: Enumerating all controls including compound controls
|
|
=============================================================
|
|
|
|
.. code-block:: c
|
|
|
|
struct v4l2_query_ext_ctrl query_ext_ctrl;
|
|
|
|
memset(&query_ext_ctrl, 0, sizeof(query_ext_ctrl));
|
|
|
|
query_ext_ctrl.id = V4L2_CTRL_FLAG_NEXT_CTRL | V4L2_CTRL_FLAG_NEXT_COMPOUND;
|
|
while (0 == ioctl(fd, VIDIOC_QUERY_EXT_CTRL, &query_ext_ctrl)) {
|
|
if (!(query_ext_ctrl.flags & V4L2_CTRL_FLAG_DISABLED)) {
|
|
printf("Control %s\\n", query_ext_ctrl.name);
|
|
|
|
if (query_ext_ctrl.type == V4L2_CTRL_TYPE_MENU)
|
|
enumerate_menu(query_ext_ctrl.id);
|
|
}
|
|
|
|
query_ext_ctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL | V4L2_CTRL_FLAG_NEXT_COMPOUND;
|
|
}
|
|
if (errno != EINVAL) {
|
|
perror("VIDIOC_QUERY_EXT_CTRL");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
Example: Enumerating all user controls (old style)
|
|
==================================================
|
|
|
|
.. code-block:: c
|
|
|
|
|
|
memset(&queryctrl, 0, sizeof(queryctrl));
|
|
|
|
for (queryctrl.id = V4L2_CID_BASE;
|
|
queryctrl.id < V4L2_CID_LASTP1;
|
|
queryctrl.id++) {
|
|
if (0 == ioctl(fd, VIDIOC_QUERYCTRL, &queryctrl)) {
|
|
if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED)
|
|
continue;
|
|
|
|
printf("Control %s\\n", queryctrl.name);
|
|
|
|
if (queryctrl.type == V4L2_CTRL_TYPE_MENU)
|
|
enumerate_menu(queryctrl.id);
|
|
} else {
|
|
if (errno == EINVAL)
|
|
continue;
|
|
|
|
perror("VIDIOC_QUERYCTRL");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
}
|
|
|
|
for (queryctrl.id = V4L2_CID_PRIVATE_BASE;;
|
|
queryctrl.id++) {
|
|
if (0 == ioctl(fd, VIDIOC_QUERYCTRL, &queryctrl)) {
|
|
if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED)
|
|
continue;
|
|
|
|
printf("Control %s\\n", queryctrl.name);
|
|
|
|
if (queryctrl.type == V4L2_CTRL_TYPE_MENU)
|
|
enumerate_menu(queryctrl.id);
|
|
} else {
|
|
if (errno == EINVAL)
|
|
break;
|
|
|
|
perror("VIDIOC_QUERYCTRL");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
}
|
|
|
|
|
|
Example: Changing controls
|
|
==========================
|
|
|
|
.. code-block:: c
|
|
|
|
struct v4l2_queryctrl queryctrl;
|
|
struct v4l2_control control;
|
|
|
|
memset(&queryctrl, 0, sizeof(queryctrl));
|
|
queryctrl.id = V4L2_CID_BRIGHTNESS;
|
|
|
|
if (-1 == ioctl(fd, VIDIOC_QUERYCTRL, &queryctrl)) {
|
|
if (errno != EINVAL) {
|
|
perror("VIDIOC_QUERYCTRL");
|
|
exit(EXIT_FAILURE);
|
|
} else {
|
|
printf("V4L2_CID_BRIGHTNESS is not supportedn");
|
|
}
|
|
} else if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) {
|
|
printf("V4L2_CID_BRIGHTNESS is not supportedn");
|
|
} else {
|
|
memset(&control, 0, sizeof (control));
|
|
control.id = V4L2_CID_BRIGHTNESS;
|
|
control.value = queryctrl.default_value;
|
|
|
|
if (-1 == ioctl(fd, VIDIOC_S_CTRL, &control)) {
|
|
perror("VIDIOC_S_CTRL");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
}
|
|
|
|
memset(&control, 0, sizeof(control));
|
|
control.id = V4L2_CID_CONTRAST;
|
|
|
|
if (0 == ioctl(fd, VIDIOC_G_CTRL, &control)) {
|
|
control.value += 1;
|
|
|
|
/* The driver may clamp the value or return ERANGE, ignored here */
|
|
|
|
if (-1 == ioctl(fd, VIDIOC_S_CTRL, &control)
|
|
&& errno != ERANGE) {
|
|
perror("VIDIOC_S_CTRL");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
/* Ignore if V4L2_CID_CONTRAST is unsupported */
|
|
} else if (errno != EINVAL) {
|
|
perror("VIDIOC_G_CTRL");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
control.id = V4L2_CID_AUDIO_MUTE;
|
|
control.value = 1; /* silence */
|
|
|
|
/* Errors ignored */
|
|
ioctl(fd, VIDIOC_S_CTRL, &control);
|
|
|
|
.. [#f1]
|
|
The use of ``V4L2_CID_PRIVATE_BASE`` is problematic because different
|
|
drivers may use the same ``V4L2_CID_PRIVATE_BASE`` ID for different
|
|
controls. This makes it hard to programmatically set such controls
|
|
since the meaning of the control with that ID is driver dependent. In
|
|
order to resolve this drivers use unique IDs and the
|
|
``V4L2_CID_PRIVATE_BASE`` IDs are mapped to those unique IDs by the
|
|
kernel. Consider these ``V4L2_CID_PRIVATE_BASE`` IDs as aliases to
|
|
the real IDs.
|
|
|
|
Many applications today still use the ``V4L2_CID_PRIVATE_BASE`` IDs
|
|
instead of using :ref:`VIDIOC_QUERYCTRL` with
|
|
the ``V4L2_CTRL_FLAG_NEXT_CTRL`` flag to enumerate all IDs, so
|
|
support for ``V4L2_CID_PRIVATE_BASE`` is still around.
|