media/v4l/vidioc-g-modulator.rst

1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
13 VIDIOC_G_MODULATOR - VIDIOC_S_MODULATOR - Get or set modulator attributes
47 Modulators have two writable properties, an audio modulation set and the
52 this is a write-only ioctl, it does not return the actual audio
67 .. flat-table:: struct v4l2_modulator
68     :header-rows:  0
69     :stub-columns: 0
72     * - __u32
73       - ``index``
74       - Identifies the modulator, set by the application.
75     * - __u8
76       - ``name``\ [32]
77       - Name of the modulator, a NUL-terminated ASCII string.
80     * - __u32
81       - ``capability``
82       - Modulator capability flags. No flags are defined for this field,
87     * - __u32
88       - ``rangelow``
89       - The lowest tunable frequency in units of 62.5 KHz, or if the
93     * - __u32
94       - ``rangehigh``
95       - The highest tunable frequency in units of 62.5 KHz, or if the
99     * - __u32
100       - ``txsubchans``
101       - With this field applications can determine how audio sub-carriers
103 	:ref:`modulator-txsubchans`.
109 	   are assumed to have an analog or PCM audio input with 1-3
113     * - __u32
114       - ``type``
115       - :cspan:`2` Type of the modulator, see :c:type:`v4l2_tuner_type`.
116     * - __u32
117       - ``reserved``\ [3]
118       - Reserved for future extensions.
126 .. _modulator-txsubchans:
128 .. flat-table:: Modulator Audio Transmission Flags
129     :header-rows:  0
130     :stub-columns: 0
133     * - ``V4L2_TUNER_SUB_MONO``
134       - 0x0001
135       - Modulate channel 1 as mono audio, when the input has more
136 	channels, a down-mix of channel 1 and 2. This flag does not
139     * - ``V4L2_TUNER_SUB_STEREO``
140       - 0x0002
141       - Modulate channel 1 and 2 as left and right channel of a stereo
142 	audio signal. When the input has only one channel or two channels
143 	and ``V4L2_TUNER_SUB_SAP`` is also set, channel 1 is encoded as
144 	left and right channel. This flag does not combine with
147     * - ``V4L2_TUNER_SUB_LANG1``
148       - 0x0008
149       - Modulate channel 1 and 2 as primary and secondary language of a
150 	bilingual audio signal. When the input has only one channel it is
159     * - ``V4L2_TUNER_SUB_LANG2``
160       - 0x0004
161       - Same effect as ``V4L2_TUNER_SUB_SAP``.
162     * - ``V4L2_TUNER_SUB_SAP``
163       - 0x0004
164       - When combined with ``V4L2_TUNER_SUB_MONO`` the first channel is
165 	encoded as mono audio, the last channel as Second Audio Program.
166 	When the input has only one channel it is used for both audio
168 	down-mix of channel 1 and 2. When combined with
169 	``V4L2_TUNER_SUB_STEREO`` channel 1 and 2 are encoded as left and
170 	right stereo audio, channel 3 as Second Audio Program. When the
171 	input has only two channels, the first is encoded as left and
172 	right channel and the second as SAP. When the input has only one
173 	channel it is used for all audio tracks. It is not possible to
180     * - ``V4L2_TUNER_SUB_RDS``
181       - 0x0010
182       - Enable the RDS encoder for a radio FM transmitter.
187 On success 0 is returned, on error -1 and the ``errno`` variable is set
189 :ref:`Generic Error Codes <gen-errors>` chapter.