Lines Matching +full:support +full:- +full:pulse +full:- +full:signal
1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
4 .. _raw-vbi:
11 sequence of lines of an analog video signal. During VBI no picture
15 short data packages ASK modulated [#f1]_ onto the video signal. These are
19 signal, or to be added to a signal for output. The data format is
50 VBI devices shall support :ref:`video input or output <video>`,
106 .. flat-table:: struct v4l2_vbi_format
107 :header-rows: 0
108 :stub-columns: 0
111 * - __u32
112 - ``sampling_rate``
113 - Samples per second, i. e. unit 1 Hz.
114 * - __u32
115 - ``offset``
116 - Horizontal offset of the VBI image, relative to the leading edge
117 of the line synchronization pulse and counted in samples: The
120 :ref:`vbi-hsync`.
121 * - __u32
122 - ``samples_per_line``
123 -
124 * - __u32
125 - ``sample_format``
126 - Defines the sample format as in :ref:`pixfmt`, a
127 four-character-code. [#f2]_ Usually this is ``V4L2_PIX_FMT_GREY``,
130 values with the signal level. For example, the MSB does not
131 necessarily indicate if the signal is 'high' or 'low' because 128
132 may not be the mean value of the signal. Drivers shall not convert
134 * - __u32
135 - ``start``\ [#f2]_
136 - This is the scanning system line number associated with the first
138 respectively. See :ref:`vbi-525` and :ref:`vbi-625` for valid
147 * - __u32
148 - ``count``\ [#f2]_
149 - The number of lines in the first and second field image,
151 * - :cspan:`2`
162 driver. Anyway, drivers may not support single field capturing and
163 return both count values non-zero.
171 :ref:`v4l2_std_id <v4l2-std-id>` or the ``framelines`` field
174 * - __u32
175 - ``flags``
176 - See :ref:`vbifmt-flags` below. Currently only drivers set flags,
178 * - __u32
179 - ``reserved``\ [#f2]_
180 - This array is reserved for future extensions. Drivers and
185 .. _vbifmt-flags:
187 .. flat-table:: Raw VBI Format Flags
188 :header-rows: 0
189 :stub-columns: 0
192 * - ``V4L2_VBI_UNSYNC``
193 - 0x0001
194 - This flag indicates hardware which does not properly distinguish
201 * - ``V4L2_VBI_INTERLACED``
202 - 0x0002
203 - By default the two field images will be passed sequentially; all
205 (compare :ref:`field-order` ``V4L2_FIELD_SEQ_TB`` and
215 non-zero.
218 .. _vbi-hsync:
220 .. kernel-figure:: vbi_hsync.svg
226 .. _vbi-525:
228 .. kernel-figure:: vbi_525.svg
232 **Figure 4.2. ITU-R 525 line numbering (M/NTSC and M/PAL)**
234 .. _vbi-625:
236 .. kernel-figure:: vbi_625.svg
240 **Figure 4.3. ITU-R 625 line numbering**
258 .. code-block:: c
266 A VBI device may support :ref:`read/write <rw>` and/or streaming
279 ASK: Amplitude-Shift Keying. A high signal level represents a '1'
292 The valid values ar shown at :ref:`vbi-525` and :ref:`vbi-625`.