Lines Matching +full:vga +full:- +full:format
1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
13 VIDIOC_G_FBUF - VIDIOC_S_FBUF - Get or set frame buffer overlay parameters
46 The V4L2 API distinguishes destructive and non-destructive overlays. A
48 of a graphics card. A non-destructive overlay blends video images into a
49 VGA signal or graphics into a video signal. *Video Output Overlays* are
50 always non-destructive.
81 .. flat-table:: struct v4l2_framebuffer
82 :header-rows: 0
83 :stub-columns: 0
86 * - __u32
87 - ``capability``
88 -
89 - Overlay capability flags set by the driver, see
90 :ref:`framebuffer-cap`.
91 * - __u32
92 - ``flags``
93 -
94 - Overlay control flags set by application and driver, see
95 :ref:`framebuffer-flags`
96 * - void *
97 - ``base``
98 -
99 - Physical base address of the framebuffer, that is the address of
108 * - struct
109 - ``fmt``
110 -
111 - Layout of the frame buffer.
112 * -
113 - __u32
114 - ``width``
115 - Width of the frame buffer in pixels.
116 * -
117 - __u32
118 - ``height``
119 - Height of the frame buffer in pixels.
120 * -
121 - __u32
122 - ``pixelformat``
123 - The pixel format of the framebuffer.
124 * -
125 -
126 -
127 - For *non-destructive Video Overlays* this field only defines a
128 format for the struct :c:type:`v4l2_window`
130 * -
131 -
132 -
133 - For *Video Output Overlays* the driver must return a valid
134 format.
135 * -
136 -
137 -
138 - Usually this is an RGB format (for example
139 :ref:`V4L2_PIX_FMT_RGB565 <V4L2-PIX-FMT-RGB565>`) but YUV
142 ``V4L2_PIX_FMT_PAL8`` format are also permitted. The behavior of
143 the driver when an application requests a compressed format is
145 * -
146 - enum :c:type:`v4l2_field`
147 - ``field``
148 - Drivers and applications shall ignore this field. If applicable,
152 * -
153 - __u32
154 - ``bytesperline``
155 - Distance in bytes between the leftmost pixels in two adjacent
157 * - :cspan:`3`
159 This field is irrelevant to *non-destructive Video Overlays*.
169 When the image format is planar the ``bytesperline`` value applies
176 * -
177 - __u32
178 - ``sizeimage``
179 - This field is irrelevant to *non-destructive Video Overlays*.
181 format.
185 * -
186 - enum :c:type:`v4l2_colorspace`
187 - ``colorspace``
188 - This information supplements the ``pixelformat`` and must be set
190 * -
191 - __u32
192 - ``priv``
193 - Reserved. Drivers and applications must set this field to zero.
197 .. _framebuffer-cap:
199 .. flat-table:: Frame Buffer Capability Flags
200 :header-rows: 0
201 :stub-columns: 0
204 * - ``V4L2_FBUF_CAP_EXTERNOVERLAY``
205 - 0x0001
206 - The device is capable of non-destructive overlays. When the driver
209 non-destructive overlays. Video Output Overlays are in practice
210 always non-destructive.
211 * - ``V4L2_FBUF_CAP_CHROMAKEY``
212 - 0x0002
213 - The device supports clipping by chroma-keying the images. That is,
214 image pixels replace pixels in the VGA or video signal only where
215 the latter assume a certain color. Chroma-keying makes no sense
217 * - ``V4L2_FBUF_CAP_LIST_CLIPPING``
218 - 0x0004
219 - The device supports clipping using a list of clip rectangles.
221 * - ``V4L2_FBUF_CAP_BITMAP_CLIPPING``
222 - 0x0008
223 - The device supports clipping using a bit mask.
225 * - ``V4L2_FBUF_CAP_LOCAL_ALPHA``
226 - 0x0010
227 - The device supports clipping/blending using the alpha channel of
228 the framebuffer or VGA signal. Alpha blending makes no sense for
230 * - ``V4L2_FBUF_CAP_GLOBAL_ALPHA``
231 - 0x0020
232 - The device supports alpha blending using a global alpha value.
234 * - ``V4L2_FBUF_CAP_LOCAL_INV_ALPHA``
235 - 0x0040
236 - The device supports clipping/blending using the inverted alpha
237 channel of the framebuffer or VGA signal. Alpha blending makes no
239 * - ``V4L2_FBUF_CAP_SRC_CHROMAKEY``
240 - 0x0080
241 - The device supports Source Chroma-keying. Video pixels with the
242 chroma-key colors are replaced by framebuffer pixels, which is
247 .. _framebuffer-flags:
251 .. flat-table:: Frame Buffer Flags
252 :header-rows: 0
253 :stub-columns: 0
256 * - ``V4L2_FBUF_FLAG_PRIMARY``
257 - 0x0001
258 - The framebuffer is the primary graphics surface. In other words,
262 * - ``V4L2_FBUF_FLAG_OVERLAY``
263 - 0x0002
264 - If this flag is set for a video capture device, then the driver
274 relative to the top-left corner of the framebuffer and restricted
277 * - ``V4L2_FBUF_FLAG_CHROMAKEY``
278 - 0x0004
279 - Use chroma-keying. The chroma-key color is determined by the
283 * - :cspan:`2` There are no flags to enable clipping using a list of
287 * - ``V4L2_FBUF_FLAG_LOCAL_ALPHA``
288 - 0x0008
289 - Use the alpha channel of the framebuffer to clip or blend
291 output = framebuffer pixel * alpha + video pixel * (1 - alpha).
292 The actual alpha depth depends on the framebuffer pixel format.
293 * - ``V4L2_FBUF_FLAG_GLOBAL_ALPHA``
294 - 0x0010
295 - Use a global alpha value to blend the framebuffer with video
297 + video pixel * (255 - alpha)) / 255. The alpha value is
302 * - ``V4L2_FBUF_FLAG_LOCAL_INV_ALPHA``
303 - 0x0020
304 - Like ``V4L2_FBUF_FLAG_LOCAL_ALPHA``, use the alpha channel of the
307 framebuffer pixel * (1 - alpha) + video pixel * alpha. The actual
308 alpha depth depends on the framebuffer pixel format.
309 * - ``V4L2_FBUF_FLAG_SRC_CHROMAKEY``
310 - 0x0040
311 - Use source chroma-keying. The source chroma-key color is
315 and :ref:`osd`. Both chroma-keying are mutual exclusive to each
322 On success 0 is returned, on error -1 and the ``errno`` variable is set
324 :ref:`Generic Error Codes <gen-errors>` chapter.