media/v4l/control.rst

1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
9 Devices typically have a number of user-settable controls such as
21 pre-defined control IDs have the prefix ``V4L2_CID_``, and are listed in
22 :ref:`control-id`. The ID is used when querying the attributes of a
27 the user is supposed to understand. When the purpose is non-intuitive
28 the driver writer should provide a user manual, a user interface plug-in
57 .. _control-id:
68 ``V4L2_CID_BRIGHTNESS`` ``(integer)``
71 ``V4L2_CID_CONTRAST`` ``(integer)``
74 ``V4L2_CID_SATURATION`` ``(integer)``
77 ``V4L2_CID_HUE`` ``(integer)``
80 ``V4L2_CID_AUDIO_VOLUME`` ``(integer)``
84 ``V4L2_CID_AUDIO_BALANCE`` ``(integer)``
88 ``V4L2_CID_AUDIO_BASS`` ``(integer)``
91 ``V4L2_CID_AUDIO_TREBLE`` ``(integer)``
103 ``V4L2_CID_BLACK_LEVEL`` ``(integer)``
117 ``V4L2_CID_RED_BALANCE`` ``(integer)``
120 ``V4L2_CID_BLUE_BALANCE`` ``(integer)``
123 ``V4L2_CID_GAMMA`` ``(integer)``
126 ``V4L2_CID_WHITENESS`` ``(integer)``
127     Whiteness for grey-scale devices. This is a synonym for
131 ``V4L2_CID_EXPOSURE`` ``(integer)``
137 ``V4L2_CID_GAIN`` ``(integer)``
152 .. _v4l2-power-line-frequency:
170 ``V4L2_CID_WHITE_BALANCE_TEMPERATURE`` ``(integer)``
177 ``V4L2_CID_SHARPNESS`` ``(integer)``
181 ``V4L2_CID_BACKLIGHT_COMPENSATION`` ``(integer)``
188 ``V4L2_CID_CHROMA_GAIN`` ``(integer)``
196 .. _v4l2-colorfx:
205 .. flat-table::
206     :header-rows:  0
207     :stub-columns: 0
210     * - ``V4L2_COLORFX_NONE``
211       - Color effect is disabled.
212     * - ``V4L2_COLORFX_ANTIQUE``
213       - An aging (old photo) effect.
214     * - ``V4L2_COLORFX_ART_FREEZE``
215       - Frost color effect.
216     * - ``V4L2_COLORFX_AQUA``
217       - Water color, cool tone.
218     * - ``V4L2_COLORFX_BW``
219       - Black and white.
220     * - ``V4L2_COLORFX_EMBOSS``
221       - Emboss, the highlights and shadows replace light/dark boundaries
223     * - ``V4L2_COLORFX_GRASS_GREEN``
224       - Grass green.
225     * - ``V4L2_COLORFX_NEGATIVE``
226       - Negative.
227     * - ``V4L2_COLORFX_SEPIA``
228       - Sepia tone.
229     * - ``V4L2_COLORFX_SKETCH``
230       - Sketch.
231     * - ``V4L2_COLORFX_SKIN_WHITEN``
232       - Skin whiten.
233     * - ``V4L2_COLORFX_SKY_BLUE``
234       - Sky blue.
235     * - ``V4L2_COLORFX_SOLARIZATION``
236       - Solarization, the image is partially reversed in tone, only color
238     * - ``V4L2_COLORFX_SILHOUETTE``
239       - Silhouette (outline).
240     * - ``V4L2_COLORFX_VIVID``
241       - Vivid colors.
242     * - ``V4L2_COLORFX_SET_CBCR``
243       - The Cb and Cr chroma components are replaced by fixed coefficients
245     * - ``V4L2_COLORFX_SET_RGB``
246       - The RGB components are replaced by the fixed RGB components determined
250 ``V4L2_CID_COLORFX_RGB`` ``(integer)``
257 ``V4L2_CID_COLORFX_CBCR`` ``(integer)``
266 ``V4L2_CID_ROTATE`` ``(integer)``
274 ``V4L2_CID_BG_COLOR`` ``(integer)``
277     value is interpreted as bits 0-7 Red color information, bits 8-15
278     Green color information, bits 16-23 Blue color information and bits
279     24-31 must be zero.
285 ``V4L2_CID_MIN_BUFFERS_FOR_CAPTURE`` ``(integer)``
286     This is a read-only control that can be read by the application and
291 ``V4L2_CID_MIN_BUFFERS_FOR_OUTPUT`` ``(integer)``
292     This is a read-only control that can be read by the application and
297 .. _v4l2-alpha-component:
299 ``V4L2_CID_ALPHA_COMPONENT`` ``(integer)``
301     queue of a mem-to-mem device) produces a frame format that includes
303     :ref:`packed RGB image formats <pixfmt-rgb>`) and the alpha value
304     is not defined by the device or the mem-to-mem input data this
306     When an output device (or output queue of a mem-to-mem device)
336 .. code-block:: c
343 	printf("  Menu items:\\n");
352 		printf("  %s\\n", querymenu.name);
362 	    printf("Control %s\\n", queryctrl.name);
378 .. code-block:: c
387 	    printf("Control %s\\n", query_ext_ctrl.name);
403 .. code-block:: c
415 	    printf("Control %s\\n", queryctrl.name);
434 	    printf("Control %s\\n", queryctrl.name);
451 .. code-block:: c
459     if (-1 == ioctl(fd, VIDIOC_QUERYCTRL, &queryctrl)) {
464 	    printf("V4L2_CID_BRIGHTNESS is not supported\n");
467 	printf("V4L2_CID_BRIGHTNESS is not supported\n");
473 	if (-1 == ioctl(fd, VIDIOC_S_CTRL, &control)) {
487 	if (-1 == ioctl(fd, VIDIOC_S_CTRL, &control)