| <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> |
| <HTML |
| ><HEAD |
| ><TITLE |
| >Tuners and Modulators</TITLE |
| ><META |
| NAME="GENERATOR" |
| CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK |
| REL="HOME" |
| TITLE="Video for Linux Two API Specification" |
| HREF="book1.htm"><LINK |
| REL="UP" |
| TITLE="Common API Elements" |
| HREF="c174.htm"><LINK |
| REL="PREVIOUS" |
| TITLE="Audio Inputs and Outputs" |
| HREF="x341.htm"><LINK |
| REL="NEXT" |
| TITLE="Video Standards" |
| HREF="x448.htm"></HEAD |
| ><BODY |
| CLASS="SECTION" |
| BGCOLOR="#FFFFFF" |
| TEXT="#000000" |
| LINK="#0000FF" |
| VLINK="#840084" |
| ALINK="#0000FF" |
| ><DIV |
| CLASS="NAVHEADER" |
| ><TABLE |
| SUMMARY="Header navigation table" |
| WIDTH="100%" |
| BORDER="0" |
| CELLPADDING="0" |
| CELLSPACING="0" |
| ><TR |
| ><TH |
| COLSPAN="3" |
| ALIGN="center" |
| >Video for Linux Two API Specification: Revision 0.24</TH |
| ></TR |
| ><TR |
| ><TD |
| WIDTH="10%" |
| ALIGN="left" |
| VALIGN="bottom" |
| ><A |
| HREF="x341.htm" |
| ACCESSKEY="P" |
| >Prev</A |
| ></TD |
| ><TD |
| WIDTH="80%" |
| ALIGN="center" |
| VALIGN="bottom" |
| >Chapter 1. Common API Elements</TD |
| ><TD |
| WIDTH="10%" |
| ALIGN="right" |
| VALIGN="bottom" |
| ><A |
| HREF="x448.htm" |
| ACCESSKEY="N" |
| >Next</A |
| ></TD |
| ></TR |
| ></TABLE |
| ><HR |
| ALIGN="LEFT" |
| WIDTH="100%"></DIV |
| ><DIV |
| CLASS="SECTION" |
| ><H1 |
| CLASS="SECTION" |
| ><A |
| NAME="TUNER" |
| >1.6. Tuners and Modulators</A |
| ></H1 |
| ><DIV |
| CLASS="SECTION" |
| ><H2 |
| CLASS="SECTION" |
| ><A |
| NAME="AEN396" |
| >1.6.1. Tuners</A |
| ></H2 |
| ><P |
| >Video input devices can have one or more tuners |
| demodulating a RF signal. Each tuner is associated with one or more |
| video inputs, depending on the number of RF connectors on the tuner. |
| The <CODE |
| CLASS="STRUCTFIELD" |
| >type</CODE |
| > field of the respective |
| struct <A |
| HREF="r8936.htm#V4L2-INPUT" |
| >v4l2_input</A |
| > returned by the <A |
| HREF="r8936.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_ENUMINPUT</CODE |
| ></A |
| > ioctl is set to |
| <CODE |
| CLASS="CONSTANT" |
| >V4L2_INPUT_TYPE_TUNER</CODE |
| > and its |
| <CODE |
| CLASS="STRUCTFIELD" |
| >tuner</CODE |
| > field contains the index number of |
| the tuner.</P |
| ><P |
| >Radio devices have exactly one tuner with index zero, no |
| video inputs.</P |
| ><P |
| >To query and change tuner properties applications use the |
| <A |
| HREF="r12342.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_G_TUNER</CODE |
| ></A |
| > and <A |
| HREF="r12342.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_S_TUNER</CODE |
| ></A |
| > ioctl, respectively. The |
| struct <A |
| HREF="r12342.htm#V4L2-TUNER" |
| >v4l2_tuner</A |
| > returned by <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_G_TUNER</CODE |
| > also |
| contains signal status information applicable when the tuner of the |
| current video input, or a radio tuner is queried. Note that |
| <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_S_TUNER</CODE |
| > does not switch the current tuner, |
| when there is more than one at all. The tuner is solely determined by |
| the current video input. Drivers must support both ioctls and set the |
| <CODE |
| CLASS="CONSTANT" |
| >V4L2_CAP_TUNER</CODE |
| > flag in the struct <A |
| HREF="r13105.htm#V4L2-CAPABILITY" |
| >v4l2_capability</A |
| > |
| returned by the <A |
| HREF="r13105.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_QUERYCAP</CODE |
| ></A |
| > ioctl when the device has one or |
| more tuners.</P |
| ></DIV |
| ><DIV |
| CLASS="SECTION" |
| ><H2 |
| CLASS="SECTION" |
| ><A |
| NAME="AEN418" |
| >1.6.2. Modulators</A |
| ></H2 |
| ><P |
| >Video output devices can have one or more modulators, uh, |
| modulating a video signal for radiation or connection to the antenna |
| input of a TV set or video recorder. Each modulator is associated with |
| one or more video outputs, depending on the number of RF connectors on |
| the modulator. The <CODE |
| CLASS="STRUCTFIELD" |
| >type</CODE |
| > field of the |
| respective struct <A |
| HREF="r9149.htm#V4L2-OUTPUT" |
| >v4l2_output</A |
| > returned by the <A |
| HREF="r9149.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_ENUMOUTPUT</CODE |
| ></A |
| > ioctl is |
| set to <CODE |
| CLASS="CONSTANT" |
| >V4L2_OUTPUT_TYPE_MODULATOR</CODE |
| > and its |
| <CODE |
| CLASS="STRUCTFIELD" |
| >modulator</CODE |
| > field contains the index number |
| of the modulator. This specification does not define radio output |
| devices.</P |
| ><P |
| >To query and change modulator properties applications use |
| the <A |
| HREF="r11430.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_G_MODULATOR</CODE |
| ></A |
| > and <A |
| HREF="r11430.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_S_MODULATOR</CODE |
| ></A |
| > ioctl. Note that |
| <CODE |
| CLASS="CONSTANT" |
| >VIDIOC_S_MODULATOR</CODE |
| > does not switch the current |
| modulator, when there is more than one at all. The modulator is solely |
| determined by the current video output. Drivers must support both |
| ioctls and set the <CODE |
| CLASS="CONSTANT" |
| >V4L2_CAP_TUNER</CODE |
| > (sic) flag in |
| the struct <A |
| HREF="r13105.htm#V4L2-CAPABILITY" |
| >v4l2_capability</A |
| > returned by the <A |
| HREF="r13105.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_QUERYCAP</CODE |
| ></A |
| > ioctl when the |
| device has one or more modulators.</P |
| ></DIV |
| ><DIV |
| CLASS="SECTION" |
| ><H2 |
| CLASS="SECTION" |
| ><A |
| NAME="AEN437" |
| >1.6.3. Radio Frequency</A |
| ></H2 |
| ><P |
| >To get and set the tuner or modulator radio frequency |
| applications use the <A |
| HREF="r11094.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_G_FREQUENCY</CODE |
| ></A |
| > and <A |
| HREF="r11094.htm" |
| ><CODE |
| CLASS="CONSTANT" |
| >VIDIOC_S_FREQUENCY</CODE |
| ></A |
| > |
| ioctl which both take a pointer to a struct <A |
| HREF="r11094.htm#V4L2-FREQUENCY" |
| >v4l2_frequency</A |
| >. These ioctls |
| are used for TV and radio devices alike. Drivers must support both |
| ioctls when the tuner or modulator ioctls are supported, or |
| when the device is a radio device.</P |
| ></DIV |
| ><DIV |
| CLASS="SECTION" |
| ><H2 |
| CLASS="SECTION" |
| ><A |
| NAME="AEN445" |
| >1.6.4. Satellite Receivers</A |
| ></H2 |
| ><P |
| >To be discussed. See also |
| proposals by Peter Schlaf, video4linux-list@redhat.com on 23 Oct 2002, |
| subject: "Re: [V4L] Re: v4l2 api".</P |
| ></DIV |
| ></DIV |
| ><DIV |
| CLASS="NAVFOOTER" |
| ><HR |
| ALIGN="LEFT" |
| WIDTH="100%"><TABLE |
| SUMMARY="Footer navigation table" |
| WIDTH="100%" |
| BORDER="0" |
| CELLPADDING="0" |
| CELLSPACING="0" |
| ><TR |
| ><TD |
| WIDTH="33%" |
| ALIGN="left" |
| VALIGN="top" |
| ><A |
| HREF="x341.htm" |
| ACCESSKEY="P" |
| >Prev</A |
| ></TD |
| ><TD |
| WIDTH="34%" |
| ALIGN="center" |
| VALIGN="top" |
| ><A |
| HREF="book1.htm" |
| ACCESSKEY="H" |
| >Home</A |
| ></TD |
| ><TD |
| WIDTH="33%" |
| ALIGN="right" |
| VALIGN="top" |
| ><A |
| HREF="x448.htm" |
| ACCESSKEY="N" |
| >Next</A |
| ></TD |
| ></TR |
| ><TR |
| ><TD |
| WIDTH="33%" |
| ALIGN="left" |
| VALIGN="top" |
| >Audio Inputs and Outputs</TD |
| ><TD |
| WIDTH="34%" |
| ALIGN="center" |
| VALIGN="top" |
| ><A |
| HREF="c174.htm" |
| ACCESSKEY="U" |
| >Up</A |
| ></TD |
| ><TD |
| WIDTH="33%" |
| ALIGN="right" |
| VALIGN="top" |
| >Video Standards</TD |
| ></TR |
| ></TABLE |
| ></DIV |
| ></BODY |
| ></HTML |
| > |