doc/spec/r8936.htm

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>ioctl VIDIOC_ENUMINPUT</TITLE
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>Video for Linux Two API Specification: Revision 0.24</TH
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><H1
><A
NAME="VIDIOC-ENUMINPUT"
></A
>ioctl VIDIOC_ENUMINPUT</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN8940"
></A
><H2
>Name</H2
>VIDIOC_ENUMINPUT&nbsp;--&nbsp;Enumerate video inputs</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN8943"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><P
></P
><A
NAME="AEN8944"
></A
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int ioctl</CODE
>(int fd, int request, struct v4l2_input
*argp);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN8954"
></A
><H2
>Arguments</H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><CODE
CLASS="PARAMETER"
>fd</CODE
></DT
><DD
><P
>File descriptor returned by <A
HREF="r14090.htm"
><CODE
CLASS="FUNCTION"
>open()</CODE
></A
>.</P
></DD
><DT
><CODE
CLASS="PARAMETER"
>request</CODE
></DT
><DD
><P
>VIDIOC_ENUMINPUT</P
></DD
><DT
><CODE
CLASS="PARAMETER"
>argp</CODE
></DT
><DD
><P
></P
></DD
></DL
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN8974"
></A
><H2
>Description</H2
><P
>To query the attributes of a video input applications
initialize the <CODE
CLASS="STRUCTFIELD"
>index</CODE
> field of struct&nbsp;<A
HREF="r8936.htm#V4L2-INPUT"
>v4l2_input</A
>
and call the <CODE
CLASS="CONSTANT"
>VIDIOC_ENUMINPUT</CODE
> ioctl with a
pointer to this structure. Drivers fill the rest of the structure or
return an <SPAN
CLASS="ERRORCODE"
>EINVAL</SPAN
> error code when the index is out of bounds. To enumerate all
inputs applications shall begin at index zero, incrementing by one
until the driver returns <SPAN
CLASS="ERRORCODE"
>EINVAL</SPAN
>.</P
><DIV
CLASS="TABLE"
><A
NAME="V4L2-INPUT"
></A
><P
><B
>Table 1. struct <CODE
CLASS="STRUCTNAME"
>v4l2_input</CODE
></B
></P
><TABLE
BORDER="0"
FRAME="void"
WIDTH="100%"
CLASS="CALSTABLE"
><COL
WIDTH="25%"
TITLE="C1"><COL
WIDTH="25%"
TITLE="C2"><COL
WIDTH="50%"
TITLE="C3"><TBODY
VALIGN="TOP"
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>index</CODE
></TD
><TD
>Identifies the input, set by the
application.</TD
></TR
><TR
><TD
>__u8</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>name</CODE
>[32]</TD
><TD
>Name of the video input, a NUL-terminated ASCII
string, for example: "Vin (Composite 2)". This information is intended
for the user, preferably the connector label on the device itself.</TD
></TR
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>type</CODE
></TD
><TD
>Type of the input, see <A
HREF="r8936.htm#INPUT-TYPE"
>Table 2</A
>.</TD
></TR
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>audioset</CODE
></TD
><TD
><P
>Drivers can enumerate up to 32 video and
audio inputs. This field shows which audio inputs were selectable as
audio source if this was the currently selected video input. It is a
bit mask. The LSB corresponds to audio input 0, the MSB to input 31.
Any number of bits can be set, or none.</P
><P
>When the driver
does not enumerate audio inputs no bits must be set. Applications
shall not interpret this as lack of audio support. Some drivers
automatically select audio sources and do not enumerate them since
there is no choice anyway.</P
><P
>For details on audio inputs and
how to select the current input see <A
HREF="x341.htm"
>Section 1.5</A
>.</P
></TD
></TR
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>tuner</CODE
></TD
><TD
>Capture devices can have zero or more tuners (RF
demodulators). When the <CODE
CLASS="STRUCTFIELD"
>type</CODE
> is set to
<CODE
CLASS="CONSTANT"
>V4L2_INPUT_TYPE_TUNER</CODE
> this is an RF connector and
this field identifies the tuner. It corresponds to
struct&nbsp;<A
HREF="r12342.htm#V4L2-TUNER"
>v4l2_tuner</A
> field <CODE
CLASS="STRUCTFIELD"
>index</CODE
>. For details on
tuners see <A
HREF="x394.htm"
>Section 1.6</A
>.</TD
></TR
><TR
><TD
><A
HREF="r9288.htm#V4L2-STD-ID"
>v4l2_std_id</A
></TD
><TD
><CODE
CLASS="STRUCTFIELD"
>std</CODE
></TD
><TD
>Every video input supports one or more different
video standards. This field is a set of all supported standards. For
details on video standards and how to switch see <A
HREF="x448.htm"
>Section 1.7</A
>.</TD
></TR
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>status</CODE
></TD
><TD
>This field provides status information about the
input. See <A
HREF="r8936.htm#INPUT-STATUS"
>Table 3</A
> for flags.
<CODE
CLASS="STRUCTFIELD"
>status</CODE
> is only valid when this is the
current input.</TD
></TR
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>reserved</CODE
>[4]</TD
><TD
>Reserved for future extensions. Drivers must set
the array to zero.</TD
></TR
></TBODY
></TABLE
></DIV
><DIV
CLASS="TABLE"
><A
NAME="INPUT-TYPE"
></A
><P
><B
>Table 2. Input Types</B
></P
><TABLE
BORDER="0"
FRAME="void"
WIDTH="100%"
CLASS="CALSTABLE"
><COL
WIDTH="38%"
TITLE="C1"><COL
WIDTH="12%"
TITLE="C2"><COL
WIDTH="50%"
TITLE="C3"><TBODY
VALIGN="TOP"
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_INPUT_TYPE_TUNER</CODE
></TD
><TD
>1</TD
><TD
>This input uses a tuner (RF demodulator).</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_INPUT_TYPE_CAMERA</CODE
></TD
><TD
>2</TD
><TD
>Analog baseband input, for example CVBS /
Composite Video, S-Video, RGB.</TD
></TR
></TBODY
></TABLE
></DIV
><DIV
CLASS="TABLE"
><A
NAME="INPUT-STATUS"
></A
><P
><B
>Table 3. Input Status Flags</B
></P
><TABLE
BORDER="0"
FRAME="void"
WIDTH="100%"
CLASS="CALSTABLE"
><COL
WIDTH="33%"
TITLE="C1"><COL
WIDTH="33%"
ALIGN="CENTER"
TITLE="C2"><COL
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TITLE="C3"><TBODY
VALIGN="TOP"
><TR
><TD
COLSPAN="3"
ALIGN="LEFT"
>General</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_NO_POWER</CODE
></TD
><TD
>0x00000001</TD
><TD
>Attached device is off.</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_NO_SIGNAL</CODE
></TD
><TD
>0x00000002</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_NO_COLOR</CODE
></TD
><TD
>0x00000004</TD
><TD
>The hardware supports color decoding, but does not
detect color modulation in the signal.</TD
></TR
><TR
><TD
COLSPAN="3"
ALIGN="LEFT"
>Analog Video</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_NO_H_LOCK</CODE
></TD
><TD
>0x00000100</TD
><TD
>No horizontal sync lock.</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_COLOR_KILL</CODE
></TD
><TD
>0x00000200</TD
><TD
>A color killer circuit automatically disables color
decoding when it detects no color modulation. When this flag is set
the color killer is enabled <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>and</I
></SPAN
> has shut off
color decoding.</TD
></TR
><TR
><TD
COLSPAN="3"
ALIGN="LEFT"
>Digital Video</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_NO_SYNC</CODE
></TD
><TD
>0x00010000</TD
><TD
>No synchronization lock.</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_NO_EQU</CODE
></TD
><TD
>0x00020000</TD
><TD
>No equalizer lock.</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_NO_CARRIER</CODE
></TD
><TD
>0x00040000</TD
><TD
>Carrier recovery failed.</TD
></TR
><TR
><TD
COLSPAN="3"
ALIGN="LEFT"
>VCR and Set-Top Box</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_MACROVISION</CODE
></TD
><TD
>0x01000000</TD
><TD
>Macrovision is an analog copy prevention system
mangling the video signal to confuse video recorders. When this
flag is set Macrovision has been detected.</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_NO_ACCESS</CODE
></TD
><TD
>0x02000000</TD
><TD
>Conditional access denied.</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_IN_ST_VTR</CODE
></TD
><TD
>0x04000000</TD
><TD
>VTR time constant. [?]</TD
></TR
></TBODY
></TABLE
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN9135"
></A
><H2
>Return Value</H2
><P
>On success <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> is returned, on error <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> and the <CODE
CLASS="VARNAME"
>errno</CODE
> variable is set appropriately:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><SPAN
CLASS="ERRORCODE"
>EINVAL</SPAN
></DT
><DD
><P
>The struct&nbsp;<A
HREF="r8936.htm#V4L2-INPUT"
>v4l2_input</A
> <CODE
CLASS="STRUCTFIELD"
>index</CODE
> is
out of bounds.</P
></DD
></DL
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