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
39 ``index`` field and zero out the ``reserved`` array of a struct
43 index is out of bounds. To enumerate all modulators applications shall
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
146 	driver does not support stereo audio it shall fall back to mono.
147     * - ``V4L2_TUNER_SUB_LANG1``
148       - 0x0008
149       - Modulate channel 1 and 2 as primary and secondary language of a
157 	return an ``EINVAL`` error code and the driver shall fall back to mono
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.
167 	tracks. When the input has three channels the mono track is a
168 	down-mix of channel 1 and 2. When combined with
179 	driver shall fall back to mono or stereo mode.
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.
193     out of bounds.