diff options
Diffstat (limited to 'Documentation/media/uapi/v4l/dev-meta.rst')
| -rw-r--r-- | Documentation/media/uapi/v4l/dev-meta.rst | 58 |
1 files changed, 0 insertions, 58 deletions
diff --git a/Documentation/media/uapi/v4l/dev-meta.rst b/Documentation/media/uapi/v4l/dev-meta.rst deleted file mode 100644 index 62518adfe37b..000000000000 --- a/Documentation/media/uapi/v4l/dev-meta.rst +++ /dev/null @@ -1,58 +0,0 @@ -.. -*- coding: utf-8; mode: rst -*- - -.. _metadata: - -****************** -Metadata Interface -****************** - -Metadata refers to any non-image data that supplements video frames with -additional information. This may include statistics computed over the image -or frame capture parameters supplied by the image source. This interface is -intended for transfer of metadata to userspace and control of that operation. - -The metadata interface is implemented on video capture device nodes. The device -can be dedicated to metadata or can implement both video and metadata capture -as specified in its reported capabilities. - -Querying Capabilities -===================== - -Device nodes supporting the metadata interface set the ``V4L2_CAP_META_CAPTURE`` -flag in the ``device_caps`` field of the -:c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP` -ioctl. That flag means the device can capture metadata to memory. - -At least one of the read/write or streaming I/O methods must be supported. - - -Data Format Negotiation -======================= - -The metadata device uses the :ref:`format` ioctls to select the capture format. -The metadata buffer content format is bound to that selected format. In addition -to the basic :ref:`format` ioctls, the :c:func:`VIDIOC_ENUM_FMT` ioctl must be -supported as well. - -To use the :ref:`format` ioctls applications set the ``type`` field of the -:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_META_CAPTURE`` and use the -:c:type:`v4l2_meta_format` ``meta`` member of the ``fmt`` union as needed per -the desired operation. Both drivers and applications must set the remainder of -the :c:type:`v4l2_format` structure to 0. - -.. _v4l2-meta-format: - -.. flat-table:: struct v4l2_meta_format - :header-rows: 0 - :stub-columns: 0 - :widths: 1 1 2 - - * - __u32 - - ``dataformat`` - - The data format, set by the application. This is a little endian - :ref:`four character code <v4l2-fourcc>`. V4L2 defines metadata formats - in :ref:`meta-formats`. - * - __u32 - - ``buffersize`` - - Maximum buffer size in bytes required for data. The value is set by the - driver. |