1 .. SPDX-License-Identifier: GFDL-1.1-no-invari
2
3 .. _planar-apis:
4
5 *****************************
6 Single- and multi-planar APIs
7 *****************************
8
9 Some devices require data for each input or ou
10 placed in discontiguous memory buffers. In suc
11 has to be addressed using more than one memory
12 per "plane". A plane is a sub-buffer of the cu
13 of such formats see :ref:`pixfmt`.
14
15 Initially, V4L2 API did not support multi-plan
16 extensions has been introduced to handle them.
17 constitute what is being referred to as the "m
18
19 Some of the V4L2 API calls and structures are
20 depending on whether single- or multi-planar A
21 application can choose whether to use one or t
22 corresponding buffer type to its ioctl calls.
23 buffer types are suffixed with an ``_MPLANE``
24 available multi-planar buffer types see enum
25 :c:type:`v4l2_buf_type`.
26
27
28 Multi-planar formats
29 ====================
30
31 Multi-planar API introduces new multi-planar f
32 a separate set of FourCC codes. It is importan
33 the multi-planar API and a multi-planar format
34 can handle all single-planar formats as well (
35 in multi-planar API structures), while the sin
36 handle multi-planar formats.
37
38
39 Calls that distinguish between single and mult
40 ==============================================
41
42 :ref:`VIDIOC_QUERYCAP <VIDIOC_QUERYCAP>`
43 Two additional multi-planar capabilities a
44 together with non-multi-planar ones for de
45 single- and multi-planar formats.
46
47 :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`, :ref:`VIDI
48 New structures for describing multi-planar
49 :c:type:`v4l2_pix_format_mplane` and
50 struct :c:type:`v4l2_plane_pix_format`.
51 Drivers may define new multi-planar format
52 FourCC codes from the existing single-plan
53
54 :ref:`VIDIOC_QBUF <VIDIOC_QBUF>`, :ref:`VIDIOC
55 A new struct :c:type:`v4l2_plane` structur
56 describing planes is added. Arrays of this
57 the new ``m.planes`` field of struct
58 :c:type:`v4l2_buffer`.
59
60 :ref:`VIDIOC_REQBUFS <VIDIOC_REQBUFS>`
61 Will allocate multi-planar buffers as requ
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