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| >Video for Linux Two API Specification: Revision 0.24</TH |
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| ><H1 |
| ><A |
| NAME="VIDIOC-G-AUDIOOUT" |
| ></A |
| >ioctl VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT</H1 |
| ><DIV |
| CLASS="REFNAMEDIV" |
| ><A |
| NAME="AEN9692" |
| ></A |
| ><H2 |
| >Name</H2 |
| >VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT -- Query or select the current audio output</DIV |
| ><DIV |
| CLASS="REFSYNOPSISDIV" |
| ><A |
| NAME="AEN9696" |
| ></A |
| ><H2 |
| >Synopsis</H2 |
| ><DIV |
| CLASS="FUNCSYNOPSIS" |
| ><P |
| ></P |
| ><A |
| NAME="AEN9697" |
| ></A |
| ><P |
| ><CODE |
| ><CODE |
| CLASS="FUNCDEF" |
| >int ioctl</CODE |
| >(int fd, int request, struct v4l2_audioout *argp);</CODE |
| ></P |
| ><P |
| ></P |
| ></DIV |
| ><DIV |
| CLASS="FUNCSYNOPSIS" |
| ><P |
| ></P |
| ><A |
| NAME="AEN9707" |
| ></A |
| ><P |
| ><CODE |
| ><CODE |
| CLASS="FUNCDEF" |
| >int ioctl</CODE |
| >(int fd, int request, const struct v4l2_audioout *argp);</CODE |
| ></P |
| ><P |
| ></P |
| ></DIV |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN9717" |
| ></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_G_AUDOUT, VIDIOC_S_AUDOUT</P |
| ></DD |
| ><DT |
| ><CODE |
| CLASS="PARAMETER" |
| >argp</CODE |
| ></DT |
| ><DD |
| ><P |
| ></P |
| ></DD |
| ></DL |
| ></DIV |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN9737" |
| ></A |
| ><H2 |
| >Description</H2 |
| ><P |
| >To query the current audio output applications zero out the |
| <CODE |
| CLASS="STRUCTFIELD" |
| >reserved</CODE |
| > array of a struct <A |
| HREF="r9688.htm#V4L2-AUDIOOUT" |
| >v4l2_audioout</A |
| > and |
| call the <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_G_AUDOUT</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 device has no audio inputs, or none which combine |
| with the current video output.</P |
| ><P |
| >Audio outputs have no writable properties. Nevertheless, to |
| select the current audio output applications can initialize the |
| <CODE |
| CLASS="STRUCTFIELD" |
| >index</CODE |
| > field and |
| <CODE |
| CLASS="STRUCTFIELD" |
| >reserved</CODE |
| > array (which in the future may |
| contain writable properties) of a |
| <CODE |
| CLASS="STRUCTNAME" |
| >v4l2_audioout</CODE |
| > structure and call the |
| <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_S_AUDOUT</CODE |
| > ioctl. Drivers switch to the |
| requested output or return the <SPAN |
| CLASS="ERRORCODE" |
| >EINVAL</SPAN |
| > 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 <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_G_AUDOUT</CODE |
| > |
| does.</P |
| ><P |
| >Note connectors on a TV card to loop back the received audio |
| signal to a sound card are not audio outputs in this sense.</P |
| ><DIV |
| CLASS="TABLE" |
| ><A |
| NAME="V4L2-AUDIOOUT" |
| ></A |
| ><P |
| ><B |
| >Table 1. struct <CODE |
| CLASS="STRUCTNAME" |
| >v4l2_audioout</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 audio output, set by the |
| driver or application.</TD |
| ></TR |
| ><TR |
| ><TD |
| >__u8</TD |
| ><TD |
| ><CODE |
| CLASS="STRUCTFIELD" |
| >name</CODE |
| >[32]</TD |
| ><TD |
| >Name of the audio output, a NUL-terminated ASCII |
| string, for example: "Line Out". 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" |
| >capability</CODE |
| ></TD |
| ><TD |
| >Audio capability flags, none defined yet. Drivers |
| must set this field to zero.</TD |
| ></TR |
| ><TR |
| ><TD |
| >__u32</TD |
| ><TD |
| ><CODE |
| CLASS="STRUCTFIELD" |
| >mode</CODE |
| ></TD |
| ><TD |
| >Audio mode, none defined yet. Drivers and |
| applications (on <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_S_AUDOUT</CODE |
| >) must set this |
| field to zero.</TD |
| ></TR |
| ><TR |
| ><TD |
| >__u32</TD |
| ><TD |
| ><CODE |
| CLASS="STRUCTFIELD" |
| >reserved</CODE |
| >[2]</TD |
| ><TD |
| >Reserved for future extensions. Drivers and |
| applications must set the array to zero.</TD |
| ></TR |
| ></TBODY |
| ></TABLE |
| ></DIV |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN9787" |
| ></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 |
| >No audio outputs combine with the current video |
| output, or the number of the selected audio output is out of bounds or |
| it does not combine, or there are no audio outputs at all and the |
| ioctl is not supported.</P |
| ></DD |
| ><DT |
| ><SPAN |
| CLASS="ERRORCODE" |
| >EBUSY</SPAN |
| ></DT |
| ><DD |
| ><P |
| >I/O is in progress, the output cannot be |
| switched.</P |
| ></DD |
| ></DL |
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