diff options
author | Mauro Carvalho Chehab <mchehab@redhat.com> | 2009-09-13 21:16:04 -0400 |
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committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2009-09-18 22:47:55 -0400 |
commit | 8e080c2e6cadada82a6b520e0c23a1cb974822d5 (patch) | |
tree | 991450ff1abba98e5313906478c33816a202ccab /Documentation/DocBook/v4l/vidioc-enum-fmt.xml | |
parent | f4e96deb4513d044653027d4921fd7592195503a (diff) |
V4L/DVB (12761): DocBook: add media API specs
The V4L and DVB API's are there for a long time. however, up to now,
no efforts were done to merge them to kernel DocBook.
This patch adds the current versions of the specs as an unique compendium.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/v4l/vidioc-enum-fmt.xml')
-rw-r--r-- | Documentation/DocBook/v4l/vidioc-enum-fmt.xml | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/Documentation/DocBook/v4l/vidioc-enum-fmt.xml b/Documentation/DocBook/v4l/vidioc-enum-fmt.xml new file mode 100644 index 000000000000..960d44615ca6 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enum-fmt.xml | |||
@@ -0,0 +1,164 @@ | |||
1 | <refentry id="vidioc-enum-fmt"> | ||
2 | <refmeta> | ||
3 | <refentrytitle>ioctl VIDIOC_ENUM_FMT</refentrytitle> | ||
4 | &manvol; | ||
5 | </refmeta> | ||
6 | |||
7 | <refnamediv> | ||
8 | <refname>VIDIOC_ENUM_FMT</refname> | ||
9 | <refpurpose>Enumerate image formats</refpurpose> | ||
10 | </refnamediv> | ||
11 | |||
12 | <refsynopsisdiv> | ||
13 | <funcsynopsis> | ||
14 | <funcprototype> | ||
15 | <funcdef>int <function>ioctl</function></funcdef> | ||
16 | <paramdef>int <parameter>fd</parameter></paramdef> | ||
17 | <paramdef>int <parameter>request</parameter></paramdef> | ||
18 | <paramdef>struct v4l2_fmtdesc | ||
19 | *<parameter>argp</parameter></paramdef> | ||
20 | </funcprototype> | ||
21 | </funcsynopsis> | ||
22 | </refsynopsisdiv> | ||
23 | |||
24 | <refsect1> | ||
25 | <title>Arguments</title> | ||
26 | |||
27 | <variablelist> | ||
28 | <varlistentry> | ||
29 | <term><parameter>fd</parameter></term> | ||
30 | <listitem> | ||
31 | <para>&fd;</para> | ||
32 | </listitem> | ||
33 | </varlistentry> | ||
34 | <varlistentry> | ||
35 | <term><parameter>request</parameter></term> | ||
36 | <listitem> | ||
37 | <para>VIDIOC_ENUM_FMT</para> | ||
38 | </listitem> | ||
39 | </varlistentry> | ||
40 | <varlistentry> | ||
41 | <term><parameter>argp</parameter></term> | ||
42 | <listitem> | ||
43 | <para></para> | ||
44 | </listitem> | ||
45 | </varlistentry> | ||
46 | </variablelist> | ||
47 | </refsect1> | ||
48 | |||
49 | <refsect1> | ||
50 | <title>Description</title> | ||
51 | |||
52 | <para>To enumerate image formats applications initialize the | ||
53 | <structfield>type</structfield> and <structfield>index</structfield> | ||
54 | field of &v4l2-fmtdesc; and call the | ||
55 | <constant>VIDIOC_ENUM_FMT</constant> ioctl with a pointer to this | ||
56 | structure. Drivers fill the rest of the structure or return an | ||
57 | &EINVAL;. All formats are enumerable by beginning at index zero and | ||
58 | incrementing by one until <errorcode>EINVAL</errorcode> is | ||
59 | returned.</para> | ||
60 | |||
61 | <table pgwide="1" frame="none" id="v4l2-fmtdesc"> | ||
62 | <title>struct <structname>v4l2_fmtdesc</structname></title> | ||
63 | <tgroup cols="3"> | ||
64 | &cs-str; | ||
65 | <tbody valign="top"> | ||
66 | <row> | ||
67 | <entry>__u32</entry> | ||
68 | <entry><structfield>index</structfield></entry> | ||
69 | <entry>Number of the format in the enumeration, set by | ||
70 | the application. This is in no way related to the <structfield> | ||
71 | pixelformat</structfield> field.</entry> | ||
72 | </row> | ||
73 | <row> | ||
74 | <entry>&v4l2-buf-type;</entry> | ||
75 | <entry><structfield>type</structfield></entry> | ||
76 | <entry>Type of the data stream, set by the application. | ||
77 | Only these types are valid here: | ||
78 | <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>, | ||
79 | <constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>, | ||
80 | <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver | ||
81 | defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant> | ||
82 | and higher.</entry> | ||
83 | </row> | ||
84 | <row> | ||
85 | <entry>__u32</entry> | ||
86 | <entry><structfield>flags</structfield></entry> | ||
87 | <entry>See <xref linkend="fmtdesc-flags" /></entry> | ||
88 | </row> | ||
89 | <row> | ||
90 | <entry>__u8</entry> | ||
91 | <entry><structfield>description</structfield>[32]</entry> | ||
92 | <entry>Description of the format, a NUL-terminated ASCII | ||
93 | string. This information is intended for the user, for example: "YUV | ||
94 | 4:2:2".</entry> | ||
95 | </row> | ||
96 | <row> | ||
97 | <entry>__u32</entry> | ||
98 | <entry><structfield>pixelformat</structfield></entry> | ||
99 | <entry>The image format identifier. This is a | ||
100 | four character code as computed by the v4l2_fourcc() | ||
101 | macro:</entry> | ||
102 | </row> | ||
103 | <row> | ||
104 | <entry spanname="hspan"><para><programlisting id="v4l2-fourcc"> | ||
105 | #define v4l2_fourcc(a,b,c,d) (((__u32)(a)<<0)|((__u32)(b)<<8)|((__u32)(c)<<16)|((__u32)(d)<<24)) | ||
106 | </programlisting></para><para>Several image formats are already | ||
107 | defined by this specification in <xref linkend="pixfmt" />. Note these | ||
108 | codes are not the same as those used in the Windows world.</para></entry> | ||
109 | </row> | ||
110 | <row> | ||
111 | <entry>__u32</entry> | ||
112 | <entry><structfield>reserved</structfield>[4]</entry> | ||
113 | <entry>Reserved for future extensions. Drivers must set | ||
114 | the array to zero.</entry> | ||
115 | </row> | ||
116 | </tbody> | ||
117 | </tgroup> | ||
118 | </table> | ||
119 | |||
120 | <table pgwide="1" frame="none" id="fmtdesc-flags"> | ||
121 | <title>Image Format Description Flags</title> | ||
122 | <tgroup cols="3"> | ||
123 | &cs-def; | ||
124 | <tbody valign="top"> | ||
125 | <row> | ||
126 | <entry><constant>V4L2_FMT_FLAG_COMPRESSED</constant></entry> | ||
127 | <entry>0x0001</entry> | ||
128 | <entry>This is a compressed format.</entry> | ||
129 | </row> | ||
130 | <row> | ||
131 | <entry><constant>V4L2_FMT_FLAG_EMULATED</constant></entry> | ||
132 | <entry>0x0002</entry> | ||
133 | <entry>This format is not native to the device but emulated | ||
134 | through software (usually libv4l2), where possible try to use a native format | ||
135 | instead for better performance.</entry> | ||
136 | </row> | ||
137 | </tbody> | ||
138 | </tgroup> | ||
139 | </table> | ||
140 | </refsect1> | ||
141 | |||
142 | <refsect1> | ||
143 | &return-value; | ||
144 | |||
145 | <variablelist> | ||
146 | <varlistentry> | ||
147 | <term><errorcode>EINVAL</errorcode></term> | ||
148 | <listitem> | ||
149 | <para>The &v4l2-fmtdesc; <structfield>type</structfield> | ||
150 | is not supported or the <structfield>index</structfield> is out of | ||
151 | bounds.</para> | ||
152 | </listitem> | ||
153 | </varlistentry> | ||
154 | </variablelist> | ||
155 | </refsect1> | ||
156 | </refentry> | ||
157 | |||
158 | <!-- | ||
159 | Local Variables: | ||
160 | mode: sgml | ||
161 | sgml-parent-document: "v4l2.sgml" | ||
162 | indent-tabs-mode: nil | ||
163 | End: | ||
164 | --> | ||