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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/userspace-api/media/v4l/ext-ctrls-fm-rx.rst | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/userspace-api/media/v4l/ext-ctrls-fm-rx.rst')
-rw-r--r-- | Documentation/userspace-api/media/v4l/ext-ctrls-fm-rx.rst | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-fm-rx.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-fm-rx.rst new file mode 100644 index 000000000..b6cfc0e82 --- /dev/null +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-fm-rx.rst @@ -0,0 +1,88 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later + +.. _fm-rx-controls: + +***************************** +FM Receiver Control Reference +***************************** + +The FM Receiver (FM_RX) class includes controls for common features of +FM Reception capable devices. + + +.. _fm-rx-control-id: + +FM_RX Control IDs +================= + +``V4L2_CID_FM_RX_CLASS (class)`` + The FM_RX class descriptor. Calling + :ref:`VIDIOC_QUERYCTRL` for this control will + return a description of this control class. + +``V4L2_CID_RDS_RECEPTION (boolean)`` + Enables/disables RDS reception by the radio tuner + +``V4L2_CID_RDS_RX_PTY (integer)`` + Gets RDS Programme Type field. This encodes up to 31 pre-defined + programme types. + +``V4L2_CID_RDS_RX_PS_NAME (string)`` + Gets the Programme Service name (PS_NAME). It is intended for + static display on a receiver. It is the primary aid to listeners in + programme service identification and selection. In Annex E of + :ref:`iec62106`, the RDS specification, there is a full + description of the correct character encoding for Programme Service + name strings. Also from RDS specification, PS is usually a single + eight character text. However, it is also possible to find receivers + which can scroll strings sized as 8 x N characters. So, this control + must be configured with steps of 8 characters. The result is it must + always contain a string with size multiple of 8. + +``V4L2_CID_RDS_RX_RADIO_TEXT (string)`` + Gets the Radio Text info. It is a textual description of what is + being broadcasted. RDS Radio Text can be applied when broadcaster + wishes to transmit longer PS names, programme-related information or + any other text. In these cases, RadioText can be used in addition to + ``V4L2_CID_RDS_RX_PS_NAME``. The encoding for Radio Text strings is + also fully described in Annex E of :ref:`iec62106`. The length of + Radio Text strings depends on which RDS Block is being used to + transmit it, either 32 (2A block) or 64 (2B block). However, it is + also possible to find receivers which can scroll strings sized as 32 + x N or 64 x N characters. So, this control must be configured with + steps of 32 or 64 characters. The result is it must always contain a + string with size multiple of 32 or 64. + +``V4L2_CID_RDS_RX_TRAFFIC_ANNOUNCEMENT (boolean)`` + If set, then a traffic announcement is in progress. + +``V4L2_CID_RDS_RX_TRAFFIC_PROGRAM (boolean)`` + If set, then the tuned programme carries traffic announcements. + +``V4L2_CID_RDS_RX_MUSIC_SPEECH (boolean)`` + If set, then this channel broadcasts music. If cleared, then it + broadcasts speech. If the transmitter doesn't make this distinction, + then it will be set. + +``V4L2_CID_TUNE_DEEMPHASIS`` + (enum) + +enum v4l2_deemphasis - + Configures the de-emphasis value for reception. A de-emphasis filter + is applied to the broadcast to accentuate the high audio + frequencies. Depending on the region, a time constant of either 50 + or 75 useconds is used. The enum v4l2_deemphasis defines possible + values for de-emphasis. Here they are: + + + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + * - ``V4L2_DEEMPHASIS_DISABLED`` + - No de-emphasis is applied. + * - ``V4L2_DEEMPHASIS_50_uS`` + - A de-emphasis of 50 uS is used. + * - ``V4L2_DEEMPHASIS_75_uS`` + - A de-emphasis of 75 uS is used. |