[media] docs-rst: better use the .. note:: tag
Change multi-line note tags to be more symetric, e. g. not starting the text together witht the tag. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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Mauro Carvalho Chehab
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@ -32,7 +32,9 @@ Arguments
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Description
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===========
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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Closes the cec device. Resources associated with the file descriptor are
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@ -38,7 +38,9 @@ Arguments
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Description
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===========
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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The :c:func:`ioctl()` function manipulates cec device parameters. The
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@ -45,7 +45,9 @@ Arguments
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Description
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===========
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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To open a cec device applications call :c:func:`open()` with the
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@ -29,7 +29,9 @@ Arguments
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Description
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===========
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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With the :c:func:`poll()` function applications can wait for CEC
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@ -3,7 +3,9 @@
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Introduction
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============
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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HDMI connectors provide a single pin for use by the Consumer Electronics
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@ -31,7 +31,9 @@ Arguments
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Description
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===========
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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All cec devices must support :ref:`ioctl CEC_ADAP_G_CAPS <CEC_ADAP_G_CAPS>`. To query
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@ -35,7 +35,9 @@ Arguments
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Description
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===========
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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To query the current CEC logical addresses, applications call
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@ -34,7 +34,9 @@ Arguments
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Description
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===========
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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To query the current physical address applications call
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@ -32,7 +32,9 @@ Arguments
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Description
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===========
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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CEC devices can send asynchronous events. These can be retrieved by
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@ -30,7 +30,9 @@ Arguments
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Description
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===========
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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By default any filehandle can use :ref:`CEC_TRANSMIT`, but in order to prevent
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@ -33,7 +33,9 @@ Arguments
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Description
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===========
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.. note:: This documents the proposed CEC API. This API is not yet finalized
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.. note::
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This documents the proposed CEC API. This API is not yet finalized
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and is currently only available as a staging kernel module.
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To receive a CEC message the application has to fill in the
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@ -17,7 +17,9 @@ using :ref:`FE_READ_STATUS`.
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Signal statistics are provided via
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:ref:`FE_GET_PROPERTY`.
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.. note:: Most statistics require the demodulator to be fully locked
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.. note::
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Most statistics require the demodulator to be fully locked
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(e. g. with FE_HAS_LOCK bit set). See
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:ref:`Frontend statistics indicators <frontend-stat-properties>` for
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more details.
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@ -8,7 +8,9 @@
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Part II - Digital TV API
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########################
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.. note:: This API is also known as **DVB API**, although it is generic
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.. note::
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This API is also known as **DVB API**, although it is generic
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enough to support all digital TV standards.
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**Version 5.10**
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@ -20,7 +20,9 @@ Also, the union didn't have any space left to be expanded without
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breaking userspace. So, the decision was to deprecate the legacy
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union/struct based approach, in favor of a properties set approach.
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.. note:: On Linux DVB API version 3, setting a frontend were done via
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.. note::
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On Linux DVB API version 3, setting a frontend were done via
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:ref:`struct dvb_frontend_parameters <dvb-frontend-parameters>`.
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This got replaced on version 5 (also called "S2API", as this API were
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added originally_enabled to provide support for DVB-S2), because the
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@ -9,7 +9,9 @@ Examples
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In this section we would like to present some examples for using the DVB
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API.
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..note:: This section is out of date, and the code below won't even
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..note::
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This section is out of date, and the code below won't even
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compile. Please refer to the
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`libdvbv5 <https://linuxtv.org/docs/libdvbv5/index.html>`__ for
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updated/recommended examples.
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@ -144,7 +144,9 @@ struct dvb_frontend_info
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- Capabilities supported by the frontend
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.. note:: The frequencies are specified in Hz for Terrestrial and Cable
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.. note::
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The frequencies are specified in Hz for Terrestrial and Cable
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systems. They're specified in kHz for Satellite systems
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@ -40,7 +40,9 @@ used to check about the locking status of the frontend after being
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tuned. The ioctl takes a pointer to an integer where the status will be
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written.
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.. note:: The size of status is actually sizeof(enum fe_status), with
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.. note::
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The size of status is actually sizeof(enum fe_status), with
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varies according with the architecture. This needs to be fixed in the
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future.
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@ -29,7 +29,9 @@ The frontend can be accessed through ``/dev/dvb/adapter?/frontend?``.
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Data types and ioctl definitions can be accessed by including
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``linux/dvb/frontend.h`` in your application.
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.. note:: Transmission via the internet (DVB-IP) is not yet handled by this
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.. note::
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Transmission via the internet (DVB-IP) is not yet handled by this
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API but a future extension is possible.
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On Satellite systems, the API support for the Satellite Equipment
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@ -42,7 +42,9 @@ that prevents them to be used with some remotes. Wide band receiver might
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also be more precise. On the other hand its disadvantage it usually
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reduced range of reception.
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.. note:: Wide band receiver might be implictly enabled if you enable
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.. note::
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Wide band receiver might be implictly enabled if you enable
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carrier reports. In that case it will be disabled as soon as you disable
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carrier reports. Trying to disable wide band receiver while carrier
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reports are active will do nothing.
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@ -37,7 +37,9 @@ The :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` and
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:ref:`VIDIOC_G_AUDOUT <VIDIOC_G_AUDOUT>` ioctls report the current
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audio input and output, respectively.
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.. note:: Note that, unlike :ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` and
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.. note::
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Note that, unlike :ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` and
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:ref:`VIDIOC_G_OUTPUT <VIDIOC_G_OUTPUT>` these ioctls return a
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structure as :ref:`VIDIOC_ENUMAUDIO` and
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:ref:`VIDIOC_ENUMAUDOUT <VIDIOC_ENUMAUDOUT>` do, not just an index.
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@ -166,12 +166,15 @@ struct v4l2_buffer
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output device because the application did not pass new data in
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time.
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.. note:: This may count the frames received e.g. over USB, without
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.. note::
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This may count the frames received e.g. over USB, without
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taking into account the frames dropped by the remote hardware due
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to limited compression throughput or bus bandwidth. These devices
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identify by not enumerating any video standards, see
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:ref:`standard`.
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- .. row 10
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- __u32
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@ -299,7 +302,9 @@ struct v4l2_plane
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``bytesused`` will be set to the size of the plane (see the
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``length`` field of this struct) by the driver.
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.. note:: Note that the actual image data starts at ``data_offset``
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.. note::
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Note that the actual image data starts at ``data_offset``
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which may not be 0.
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- .. row 2
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@ -371,7 +376,9 @@ struct v4l2_plane
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field when ``type`` refers to a capture stream, applications when
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it refers to an output stream.
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.. note:: That data_offset is included in ``bytesused``. So the
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.. note::
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That data_offset is included in ``bytesused``. So the
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size of the image in the plane is ``bytesused``-``data_offset``
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at offset ``data_offset`` from the start of the plane.
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@ -15,7 +15,9 @@ offset into a video signal.
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Applications can use the following API to select an area in the video
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signal, query the default area and the hardware limits.
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.. note:: Despite their name, the :ref:`VIDIOC_CROPCAP <VIDIOC_CROPCAP>`,
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.. note::
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Despite their name, the :ref:`VIDIOC_CROPCAP <VIDIOC_CROPCAP>`,
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:ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` and :ref:`VIDIOC_S_CROP
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<VIDIOC_G_CROP>` ioctls apply to input as well as output devices.
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@ -38,7 +40,9 @@ support scaling or the :ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` and
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:ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` ioctls. Their size (and position
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where applicable) will be fixed in this case.
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.. note:: All capture and output devices must support the
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.. note::
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All capture and output devices must support the
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:ref:`VIDIOC_CROPCAP <VIDIOC_CROPCAP>` ioctl such that applications
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can determine if scaling takes place.
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@ -144,7 +148,9 @@ reopening a device, such that piping data into or out of a device will
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work without special preparations. More advanced applications should
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ensure the parameters are suitable before starting I/O.
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.. note:: On the next two examples, a video capture device is assumed;
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.. note::
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On the next two examples, a video capture device is assumed;
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change ``V4L2_BUF_TYPE_VIDEO_CAPTURE`` for other types of device.
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Example: Resetting the cropping parameters
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@ -21,7 +21,9 @@ for both capture and output to start the codec.
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Video compression codecs use the MPEG controls to setup their codec
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parameters
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.. note:: The MPEG controls actually support many more codecs than
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.. note::
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The MPEG controls actually support many more codecs than
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just MPEG. See :ref:`mpeg-controls`.
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Memory-to-memory devices can often be used as a shared resource: you can
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@ -16,7 +16,9 @@ this interface, which borrows structures and ioctls of the
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The OSD function is accessible through the same character special file
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as the :ref:`Video Output <capture>` function.
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.. note:: The default function of such a ``/dev/video`` device is video
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.. note::
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The default function of such a ``/dev/video`` device is video
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capturing or output. The OSD function is only available after calling
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the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl.
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@ -19,7 +19,9 @@ video into a window.
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Video overlay devices are accessed through the same character special
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files as :ref:`video capture <capture>` devices.
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.. note:: The default function of a ``/dev/video`` device is video
|
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.. note::
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The default function of a ``/dev/video`` device is video
|
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capturing. The overlay function is only available after calling
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the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl.
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@ -236,7 +238,9 @@ exceeded are undefined. [#f3]_
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:ref:`VIDIOC_S_FBUF <VIDIOC_G_FBUF>`,
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:ref:`framebuffer-flags`).
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.. note:: This field was added in Linux 2.6.23, extending the
|
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.. note::
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This field was added in Linux 2.6.23, extending the
|
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structure. However the :ref:`VIDIOC_[G|S|TRY]_FMT <VIDIOC_G_FMT>`
|
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ioctls, which take a pointer to a :ref:`v4l2_format <v4l2-format>`
|
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parent structure with padding bytes at the end, are not affected.
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|
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@ -14,7 +14,9 @@ at devices capable of receiving and/or transmitting RDS information.
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For more information see the core RDS standard :ref:`iec62106` and the
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RBDS standard :ref:`nrsc4`.
|
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.. note:: Note that the RBDS standard as is used in the USA is almost
|
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.. note::
|
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|
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Note that the RBDS standard as is used in the USA is almost
|
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identical to the RDS standard. Any RDS decoder/encoder can also handle
|
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RBDS. Only some of the fields have slightly different meanings. See the
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RBDS standard for more information.
|
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|
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@ -184,7 +184,9 @@ Codec Control Reference
|
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Below all controls within the Codec control class are described. First
|
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the generic controls, then controls specific for certain hardware.
|
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|
||||
.. note:: These controls are applicable to all codecs and not just MPEG. The
|
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.. note::
|
||||
|
||||
These controls are applicable to all codecs and not just MPEG. The
|
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defines are prefixed with V4L2_CID_MPEG/V4L2_MPEG as the controls
|
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were originally made for MPEG codecs and later extended to cover all
|
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encoding formats.
|
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|
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@ -78,7 +78,9 @@ Arguments
|
|||
``MAP_SHARED`` allows applications to share the mapped memory with
|
||||
other (e. g. child-) processes.
|
||||
|
||||
.. note:: The Linux ``videobuf`` module which is used by some
|
||||
.. note::
|
||||
|
||||
The Linux ``videobuf`` module which is used by some
|
||||
drivers supports only ``MAP_SHARED``. ``MAP_PRIVATE`` requests
|
||||
copy-on-write semantics. V4L2 applications should not set the
|
||||
``MAP_PRIVATE``, ``MAP_DENYWRITE``, ``MAP_EXECUTABLE`` or ``MAP_ANON``
|
||||
|
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@ -19,7 +19,9 @@ colorspace field of struct :ref:`v4l2_pix_format <v4l2-pix-format>`
|
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or struct :ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>`
|
||||
needs to be filled in.
|
||||
|
||||
.. note:: The default R'G'B' quantization is full range for all
|
||||
.. note::
|
||||
|
||||
The default R'G'B' quantization is full range for all
|
||||
colorspaces except for BT.2020 which uses limited range R'G'B'
|
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quantization.
|
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|
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|
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@ -538,7 +538,9 @@ projectors that use the DCI-P3 colorspace. The default transfer function
|
|||
is ``V4L2_XFER_FUNC_DCI_P3``. The default Y'CbCr encoding is
|
||||
``V4L2_YCBCR_ENC_709``.
|
||||
|
||||
.. note:: Note that this colorspace does not specify a
|
||||
.. note::
|
||||
|
||||
Note that this colorspace does not specify a
|
||||
Y'CbCr encoding since it is not meant to be encoded to Y'CbCr. So this
|
||||
default Y'CbCr encoding was picked because it is the HDTV encoding. The
|
||||
default Y'CbCr quantization is limited range. The chromaticities of the
|
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|
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@ -754,7 +756,9 @@ reference are:
|
|||
- 0.316
|
||||
|
||||
|
||||
.. note:: This colorspace uses Illuminant C instead of D65 as the white
|
||||
.. note::
|
||||
|
||||
This colorspace uses Illuminant C instead of D65 as the white
|
||||
reference. To correctly convert an image in this colorspace to another
|
||||
that uses D65 you need to apply a chromatic adaptation algorithm such as
|
||||
the Bradford method.
|
||||
|
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@ -888,7 +892,9 @@ reference are identical to sRGB. The transfer function use is
|
|||
with full range quantization where Y' is scaled to [0…255] and Cb/Cr are
|
||||
scaled to [-128…128] and then clipped to [-128…127].
|
||||
|
||||
.. note:: The JPEG standard does not actually store colorspace
|
||||
.. note::
|
||||
|
||||
The JPEG standard does not actually store colorspace
|
||||
information. So if something other than sRGB is used, then the driver
|
||||
will have to set that information explicitly. Effectively
|
||||
``V4L2_COLORSPACE_JPEG`` can be considered to be an abbreviation for
|
||||
|
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|
|||
|
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@ -19,7 +19,9 @@ This format is similar to
|
|||
has a depth of 16 bits. The least significant byte is stored at lower
|
||||
memory addresses (little-endian).
|
||||
|
||||
..note:: The actual sampling precision may be lower than 16 bits,
|
||||
..note::
|
||||
|
||||
The actual sampling precision may be lower than 16 bits,
|
||||
for example 10 bits per pixel with values in tange 0 to 1023.
|
||||
|
||||
**Byte Order.**
|
||||
|
|
|
|||
|
|
@ -17,7 +17,9 @@ Description
|
|||
This is a grey-scale image with a depth of 16 bits per pixel. The most
|
||||
significant byte is stored at lower memory addresses (big-endian).
|
||||
|
||||
.. note:: Tthe actual sampling precision may be lower than 16 bits, for
|
||||
.. note::
|
||||
|
||||
The actual sampling precision may be lower than 16 bits, for
|
||||
example 10 bits per pixel with values in range 0 to 1023.
|
||||
|
||||
**Byte Order.**
|
||||
|
|
|
|||
|
|
@ -17,7 +17,9 @@ Description
|
|||
This is a grey-scale image with a depth of 16 bits per pixel. The least
|
||||
significant byte is stored at lower memory addresses (little-endian).
|
||||
|
||||
.. note:: The actual sampling precision may be lower than 16 bits, for
|
||||
.. note::
|
||||
|
||||
The actual sampling precision may be lower than 16 bits, for
|
||||
example 10 bits per pixel with values in range 0 to 1023.
|
||||
|
||||
**Byte Order.**
|
||||
|
|
|
|||
|
|
@ -41,7 +41,9 @@ output applications call the :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and
|
|||
*received* standard can be sensed with the
|
||||
:ref:`VIDIOC_QUERYSTD` ioctl.
|
||||
|
||||
..note:: The parameter of all these ioctls is a pointer to a
|
||||
..note::
|
||||
|
||||
The parameter of all these ioctls is a pointer to a
|
||||
:ref:`v4l2_std_id <v4l2-std-id>` type (a standard set), *not* an
|
||||
index into the standard enumeration. Drivers must implement all video
|
||||
standard ioctls when the device has one or more video inputs or outputs.
|
||||
|
|
|
|||
|
|
@ -28,7 +28,9 @@ struct :ref:`v4l2_tuner <v4l2-tuner>` returned by :ref:`VIDIOC_G_TUNER <VIDIOC_G
|
|||
also contains signal status information applicable when the tuner of the
|
||||
current video or radio input is queried.
|
||||
|
||||
.. note:: :ref:`VIDIOC_S_TUNER <VIDIOC_G_TUNER>` does not switch the
|
||||
.. note::
|
||||
|
||||
:ref:`VIDIOC_S_TUNER <VIDIOC_G_TUNER>` does not switch the
|
||||
current tuner, when there is more than one at all. The tuner is solely
|
||||
determined by the current video input. Drivers must support both ioctls
|
||||
and set the ``V4L2_CAP_TUNER`` flag in the struct :ref:`v4l2_capability
|
||||
|
|
|
|||
|
|
@ -88,7 +88,9 @@ To start and stop capturing or output applications call the
|
|||
:ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>` and
|
||||
:ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` ioctl.
|
||||
|
||||
.. note:: ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` removes all buffers from
|
||||
.. note::
|
||||
|
||||
ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` removes all buffers from
|
||||
both queues and unlocks all buffers as a side effect. Since there is no
|
||||
notion of doing anything "now" on a multitasking system, if an
|
||||
application needs to synchronize with another event it should examine
|
||||
|
|
|
|||
|
|
@ -39,7 +39,9 @@ initialize the ``pad`` field to 0, zero the reserved array of struct
|
|||
``VIDIOC_DV_TIMINGS_CAP`` ioctl on a video node and the driver will fill
|
||||
in the structure.
|
||||
|
||||
.. note:: Drivers may return different values after
|
||||
.. note::
|
||||
|
||||
Drivers may return different values after
|
||||
switching the video input or output.
|
||||
|
||||
When implemented by the driver DV capabilities of subdevices can be
|
||||
|
|
|
|||
|
|
@ -49,7 +49,9 @@ error code when the index is out of bounds. To enumerate all supported
|
|||
DV timings, applications shall begin at index zero, incrementing by one
|
||||
until the driver returns ``EINVAL``.
|
||||
|
||||
.. note:: Drivers may enumerate a different set of DV timings after
|
||||
.. note::
|
||||
|
||||
Drivers may enumerate a different set of DV timings after
|
||||
switching the video input or output.
|
||||
|
||||
When implemented by the driver DV timings of subdevices can be queried
|
||||
|
|
|
|||
|
|
@ -40,7 +40,9 @@ fill the rest of the structure or return an ``EINVAL`` error code. All
|
|||
formats are enumerable by beginning at index zero and incrementing by
|
||||
one until ``EINVAL`` is returned.
|
||||
|
||||
.. note:: After switching input or output the list of enumerated image
|
||||
.. note::
|
||||
|
||||
After switching input or output the list of enumerated image
|
||||
formats may be different.
|
||||
|
||||
|
||||
|
|
@ -51,7 +53,6 @@ one until ``EINVAL`` is returned.
|
|||
:stub-columns: 0
|
||||
:widths: 1 1 2
|
||||
|
||||
|
||||
- .. row 1
|
||||
|
||||
- __u32
|
||||
|
|
@ -113,7 +114,9 @@ one until ``EINVAL`` is returned.
|
|||
Several image formats are already defined by this specification in
|
||||
:ref:`pixfmt`.
|
||||
|
||||
.. attention:: These codes are not the same as those used
|
||||
.. attention::
|
||||
|
||||
These codes are not the same as those used
|
||||
in the Windows world.
|
||||
|
||||
- .. row 7
|
||||
|
|
|
|||
|
|
@ -73,7 +73,9 @@ the device supports. Only for the ``V4L2_FRMIVAL_TYPE_DISCRETE`` type
|
|||
does it make sense to increase the index value to receive more frame
|
||||
intervals.
|
||||
|
||||
.. note:: The order in which the frame intervals are returned has no
|
||||
.. note::
|
||||
|
||||
The order in which the frame intervals are returned has no
|
||||
special meaning. In particular does it not say anything about potential
|
||||
default frame intervals.
|
||||
|
||||
|
|
|
|||
|
|
@ -72,7 +72,9 @@ the ``type`` field to determine the type of frame size enumeration the
|
|||
device supports. Only for the ``V4L2_FRMSIZE_TYPE_DISCRETE`` type does
|
||||
it make sense to increase the index value to receive more frame sizes.
|
||||
|
||||
.. note:: The order in which the frame sizes are returned has no special
|
||||
.. note::
|
||||
|
||||
The order in which the frame sizes are returned has no special
|
||||
meaning. In particular does it not say anything about potential default
|
||||
format sizes.
|
||||
|
||||
|
|
|
|||
|
|
@ -129,7 +129,9 @@ of the corresponding tuner/modulator is set.
|
|||
- :cspan:`2` The supported modulation systems of this frequency
|
||||
band. See :ref:`band-modulation`.
|
||||
|
||||
.. note:: Currently only one modulation system per frequency band
|
||||
.. note::
|
||||
|
||||
Currently only one modulation system per frequency band
|
||||
is supported. More work will need to be done if multiple
|
||||
modulation systems are possible. Contact the linux-media
|
||||
mailing list
|
||||
|
|
|
|||
|
|
@ -41,7 +41,9 @@ structure or return an ``EINVAL`` error code when the index is out of
|
|||
bounds. To enumerate all audio outputs applications shall begin at index
|
||||
zero, incrementing by one until the driver returns ``EINVAL``.
|
||||
|
||||
.. note:: Connectors on a TV card to loop back the received audio signal
|
||||
.. note::
|
||||
|
||||
Connectors on a TV card to loop back the received audio signal
|
||||
to a sound card are not audio outputs in this sense.
|
||||
|
||||
See :ref:`VIDIOC_G_AUDIOout <VIDIOC_G_AUDOUT>` for a description of struct
|
||||
|
|
|
|||
|
|
@ -51,7 +51,9 @@ return the ``EINVAL`` error code when the index is out of bounds. This is a
|
|||
write-only ioctl, it does not return the current audio output attributes
|
||||
as ``VIDIOC_G_AUDOUT`` does.
|
||||
|
||||
.. note:: Connectors on a TV card to loop back the received audio signal
|
||||
.. note::
|
||||
|
||||
Connectors on a TV card to loop back the received audio signal
|
||||
to a sound card are not audio outputs in this sense.
|
||||
|
||||
|
||||
|
|
|
|||
|
|
@ -67,7 +67,9 @@ total number of available EDID blocks and it will return 0 without
|
|||
copying any data. This is an easy way to discover how many EDID blocks
|
||||
there are.
|
||||
|
||||
.. note:: If there are no EDID blocks available at all, then
|
||||
.. note::
|
||||
|
||||
If there are no EDID blocks available at all, then
|
||||
the driver will set ``blocks`` to 0 and it returns 0.
|
||||
|
||||
To set the EDID blocks of a receiver the application has to fill in the
|
||||
|
|
|
|||
|
|
@ -127,7 +127,9 @@ still cause this situation.
|
|||
to a value large enough to store the payload result and ``ENOSPC`` is
|
||||
returned.
|
||||
|
||||
.. note:: For string controls, this ``size`` field should
|
||||
.. note::
|
||||
|
||||
For string controls, this ``size`` field should
|
||||
not be confused with the length of the string. This field refers
|
||||
to the size of the memory that contains the string. The actual
|
||||
*length* of the string may well be much smaller.
|
||||
|
|
@ -265,7 +267,9 @@ still cause this situation.
|
|||
control and ``V4L2_CTRL_WHICH_DEF_VAL`` will return the default
|
||||
value of the control.
|
||||
|
||||
.. note:: You can only get the default value of the control,
|
||||
.. note::
|
||||
|
||||
You can only get the default value of the control,
|
||||
you cannot set or try it.
|
||||
|
||||
For backwards compatibility you can also use a control class here
|
||||
|
|
|
|||
|
|
@ -130,7 +130,9 @@ To change the radio frequency the
|
|||
shall be modulated. It contains a set of flags as defined in
|
||||
:ref:`modulator-txsubchans`.
|
||||
|
||||
.. note:: The tuner ``rxsubchans`` flags are reused, but the
|
||||
.. note::
|
||||
|
||||
The tuner ``rxsubchans`` flags are reused, but the
|
||||
semantics are different. Video output devices
|
||||
are assumed to have an analog or PCM audio input with 1-3
|
||||
channels. The ``txsubchans`` flags select one or more channels
|
||||
|
|
|
|||
|
|
@ -40,7 +40,9 @@ output device, applications initialize the ``type`` field of a struct
|
|||
driver fills in the remaining fields or returns an ``EINVAL`` error code if
|
||||
the sliced VBI API is unsupported or ``type`` is invalid.
|
||||
|
||||
.. note:: The ``type`` field was added, and the ioctl changed from read-only
|
||||
.. note::
|
||||
|
||||
The ``type`` field was added, and the ioctl changed from read-only
|
||||
to write-read, in Linux 2.6.19.
|
||||
|
||||
|
||||
|
|
|
|||
|
|
@ -391,7 +391,9 @@ To change the radio frequency the
|
|||
carrier for a monaural secondary language. Only
|
||||
``V4L2_TUNER_ANALOG_TV`` tuners can have this capability.
|
||||
|
||||
.. note:: The ``V4L2_TUNER_CAP_LANG2`` and ``V4L2_TUNER_CAP_SAP``
|
||||
.. note::
|
||||
|
||||
The ``V4L2_TUNER_CAP_LANG2`` and ``V4L2_TUNER_CAP_SAP``
|
||||
flags are synonyms. ``V4L2_TUNER_CAP_SAP`` applies when the tuner
|
||||
supports the ``V4L2_STD_NTSC_M`` video standard.
|
||||
|
||||
|
|
@ -502,7 +504,9 @@ To change the radio frequency the
|
|||
|
||||
- The tuner receives a Second Audio Program.
|
||||
|
||||
.. note:: The ``V4L2_TUNER_SUB_LANG2`` and ``V4L2_TUNER_SUB_SAP``
|
||||
.. note::
|
||||
|
||||
The ``V4L2_TUNER_SUB_LANG2`` and ``V4L2_TUNER_SUB_SAP``
|
||||
flags are synonyms. The ``V4L2_TUNER_SUB_SAP`` flag applies
|
||||
when the current video standard is ``V4L2_STD_NTSC_M``.
|
||||
|
||||
|
|
|
|||
|
|
@ -137,7 +137,9 @@ EIO
|
|||
``VIDIOC_DQBUF`` failed due to an internal error. Can also indicate
|
||||
temporary problems like signal loss.
|
||||
|
||||
.. note:: The driver might dequeue an (empty) buffer despite returning
|
||||
.. note::
|
||||
|
||||
The driver might dequeue an (empty) buffer despite returning
|
||||
an error, or even stop capturing. Reusing such buffer may be unsafe
|
||||
though and its details (e.g. ``index``) may not be returned either.
|
||||
It is recommended that drivers indicate recoverable errors by setting
|
||||
|
|
|
|||
|
|
@ -39,7 +39,9 @@ similar to sensing the video standard. To do so, applications call
|
|||
:ref:`v4l2_dv_timings <v4l2-dv-timings>`. Once the hardware detects
|
||||
the timings, it will fill in the timings structure.
|
||||
|
||||
.. note:: Drivers shall *not* switch timings automatically if new
|
||||
.. note::
|
||||
|
||||
Drivers shall *not* switch timings automatically if new
|
||||
timings are detected. Instead, drivers should send the
|
||||
``V4L2_EVENT_SOURCE_CHANGE`` event (if they support this) and expect
|
||||
that userspace will take action by calling :ref:`VIDIOC_QUERY_DV_TIMINGS`.
|
||||
|
|
|
|||
|
|
@ -84,7 +84,9 @@ fills the rest of the structure or returns an ``EINVAL`` error code when the
|
|||
:ref:`v4l2_queryctrl <v4l2-queryctrl>` ``minimum`` to ``maximum``,
|
||||
inclusive.
|
||||
|
||||
.. note:: It is possible for ``VIDIOC_QUERYMENU`` to return
|
||||
.. note::
|
||||
|
||||
It is possible for ``VIDIOC_QUERYMENU`` to return
|
||||
an ``EINVAL`` error code for some indices between ``minimum`` and
|
||||
``maximum``. In that case that particular menu item is not supported by
|
||||
this driver. Also note that the ``minimum`` value is not necessarily 0.
|
||||
|
|
@ -188,7 +190,9 @@ See also the examples in :ref:`control`.
|
|||
``_BITMASK``, ``_MENU`` or ``_INTEGER_MENU`` control. Not valid
|
||||
for other types of controls.
|
||||
|
||||
.. note:: Drivers reset controls to their default value only when
|
||||
.. note::
|
||||
|
||||
Drivers reset controls to their default value only when
|
||||
the driver is first loaded, never afterwards.
|
||||
|
||||
- .. row 8
|
||||
|
|
@ -306,7 +310,9 @@ See also the examples in :ref:`control`.
|
|||
``_BOOLEAN``, ``_BITMASK``, ``_MENU``, ``_INTEGER_MENU``, ``_U8``
|
||||
or ``_U16`` control. Not valid for other types of controls.
|
||||
|
||||
.. note:: Drivers reset controls to their default value only when
|
||||
.. note::
|
||||
|
||||
Drivers reset controls to their default value only when
|
||||
the driver is first loaded, never afterwards.
|
||||
|
||||
- .. row 8
|
||||
|
|
@ -728,7 +734,9 @@ See also the examples in :ref:`control`.
|
|||
case the hardware calculates the gain value based on the lighting
|
||||
conditions which can change over time.
|
||||
|
||||
.. note:: Setting a new value for a volatile control will have no
|
||||
.. note::
|
||||
|
||||
Setting a new value for a volatile control will have no
|
||||
effect and no ``V4L2_EVENT_CTRL_CH_VALUE`` will be sent, unless
|
||||
the ``V4L2_CTRL_FLAG_EXECUTE_ON_WRITE`` flag (see below) is
|
||||
also set. Otherwise the new value will just be ignored.
|
||||
|
|
|
|||
|
|
@ -43,7 +43,9 @@ will return V4L2_STD_UNKNOWN. When detection is not possible or fails,
|
|||
the set must contain all standards supported by the current video input
|
||||
or output.
|
||||
|
||||
.. note:: Drivers shall *not* switch the video standard
|
||||
.. note::
|
||||
|
||||
Drivers shall *not* switch the video standard
|
||||
automatically if a new video standard is detected. Instead, drivers
|
||||
should send the ``V4L2_EVENT_SOURCE_CHANGE`` event (if they support
|
||||
this) and expect that userspace will take action by calling
|
||||
|
|
|
|||
|
|
@ -76,7 +76,9 @@ then 0 is returned. Nothing happens in the case of ``VIDIOC_STREAMON``,
|
|||
but ``VIDIOC_STREAMOFF`` will return queued buffers to their starting
|
||||
state as mentioned above.
|
||||
|
||||
.. note:: Applications can be preempted for unknown periods right before
|
||||
.. note::
|
||||
|
||||
Applications can be preempted for unknown periods right before
|
||||
or after the ``VIDIOC_STREAMON`` or ``VIDIOC_STREAMOFF`` calls, there is
|
||||
no notion of starting or stopping "now". Buffer timestamps can be used
|
||||
to synchronize with other events.
|
||||
|
|
|
|||
|
|
@ -54,7 +54,9 @@ using the :ref:`VIDIOC_DQEVENT` ioctl.
|
|||
|
||||
- Type of the event, see :ref:`event-type`.
|
||||
|
||||
.. note:: ``V4L2_EVENT_ALL`` can be used with
|
||||
.. note::
|
||||
|
||||
``V4L2_EVENT_ALL`` can be used with
|
||||
:ref:`VIDIOC_UNSUBSCRIBE_EVENT <VIDIOC_SUBSCRIBE_EVENT>` for
|
||||
unsubscribing all events at once.
|
||||
|
||||
|
|
|
|||
|
|
@ -586,6 +586,7 @@ Cards
|
|||
-----
|
||||
|
||||
.. note::
|
||||
|
||||
For a more updated list, please check
|
||||
https://linuxtv.org/wiki/index.php/Hardware_Device_Information
|
||||
|
||||
|
|
|
|||
Загрузка…
Ссылка в новой задаче