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diff --git a/abs/core/local-website/htdocs/mythtv-doc/mythtv-HOWTO-7.html b/abs/core/local-website/htdocs/mythtv-doc/mythtv-HOWTO-7.html new file mode 100644 index 0000000..97bc763 --- /dev/null +++ b/abs/core/local-website/htdocs/mythtv-doc/mythtv-HOWTO-7.html @@ -0,0 +1,130 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> +<HTML> +<HEAD> + <META NAME="GENERATOR" CONTENT="LinuxDoc-Tools 0.9.21"> + <TITLE>Installing and using MythTV: Configuring Sound.</TITLE> + <LINK HREF="mythtv-HOWTO-8.html" REL=next> + <LINK HREF="mythtv-HOWTO-6.html" REL=previous> + <LINK HREF="mythtv-HOWTO.html#toc7" REL=contents> +</HEAD> +<BODY> +<A HREF="mythtv-HOWTO-8.html">Next</A> +<A HREF="mythtv-HOWTO-6.html">Previous</A> +<A HREF="mythtv-HOWTO.html#toc7">Contents</A> +<HR> +<H2><A NAME="s7">7.</A> <A HREF="mythtv-HOWTO.html#toc7">Configuring Sound.</A></H2> + +<P>If your video doesn't appear to be in-sync with your audio and you're +using an analog video capture card and a soundcard to capture audio, it +could be because you are listening to the real-time audio from your video +card rather than after it's been processed and synchronized to the video by +MythTV. Because MythTV is a personal video recorder, "Live TV" isn't really +live - to let you pause live TV, MythTV is actually encoding the video, +saving to disk, and then playing it back. This procedure puts your MythTV +"live" TV about 2 seconds behind real-time, so it's important that you're +not listening to the live audio. However, if you're having an issue where +the audio and video aren't synchronized by small but varying amount, it's +most likely because the sound driver that you're using doesn't have the +DSP_CAP_REALTIME capability. This was the case with ALSA (0.5), but not +with newer versions. See the +<A HREF="mythtv-HOWTO-22.html#Troubleshooting_Audio">Troubleshooting Audio</A> section for more information if you're having +issues with sound. Also, ensure that no other programs are grabbing the +audio output, like <B>arts</B> or <B>esd</B>.</P> +<P>What you need to do is to mute the "line-in" of your sound card and also +set it as the recording source.</P> +<P>There are two ways to do this. Graphically, and from the command line.</P> + +<H2><A NAME="ss7.1">7.1</A> <A HREF="mythtv-HOWTO.html#toc7.1">Graphically setting up the mixer</A> +</H2> + +<H3>Mandriva and Red Hat Linux/Fedora Core</H3> + +<P>Open Kmix by clicking K->Multimedia->Sound->Kmix for Mandriva, or +<PRE> +RedHat Menu>Sound & Video>Volume Control +</PRE> + on Red Hat/Fedora.</P> +<P>Click on Settings->Configure Make sure that "Tick Marks" and "Show +labels" have "X"'s in them. This will make it easier to find the correct +audio source. Click OK.</P> +<P>On the mixer page, look for Line-In on your sound card. You should see +two LED's - a green one at the top, and a red one at the bottom. The green +one at the top is for muting; you want to make sure that the green LED is a +dark green, meaning that it's "off". You also want to click on the red LED +so that it turns bright red, indicating that it's "ON"; this insures that +the Line-in is used as the source. Click OK, and make sure that you save +the settings so that this is your default.</P> + +<H3>Using ALSA.</H3> + +<P>To use ALSA, you'll need to correctly setup your +<CODE>asoundrc</CODE> file. Configuring this file is beyond the scope of this +HOWTO. Once ALSA is working correctly, change the output sound device in +mythfrontend->setup->Audio from <CODE>/dev/dsp</CODE> to <CODE>ALSA:default</CODE>. +This field may be edited to suit your ALSA requirements.</P> + +<H2><A NAME="ss7.2">7.2</A> <A HREF="mythtv-HOWTO.html#toc7.2">Setting the mixer from the command line</A> +</H2> + +<P>If you have installed the alsa-utils package, then the <B>amixer</B> +program can be used to setup the mixer. The "Master" volume setting is only +required on a frontend machine to ensure that the sound channels are unmuted +and configured for outputting sound. The "Line" and "Capture" controls are +required for your sound card to actually capture audio from the external +Line-in if it's connected to an analog frame grabber. Not all sound cards +have a "Capture" control, but if yours does and you don't set it then MythTV +will not capture audio.</P> +<P> +<HR> +<PRE> +Note the spelling in the following commands. +</PRE> +<HR> + +<BLOCKQUOTE><CODE> +<PRE> +$ amixer set Master,0 100%,100% unmute +$ amixer set PCM,0 100%,100% unmute +$ amixer set Line,0 75%,75% mute captur +$ amixer set Capture,0 100%,100% captur +$ su +# alsactl store +# exit +$ +</PRE> +</CODE></BLOCKQUOTE> +</P> +<P>If you have multiple sound cards, then use the <CODE>-c</CODE> parameter to +specify which card to adjust. Note that the first card will be "0", the +second will be "1", etc.</P> +<P>That takes care of setting the volume correctly, and the ALSA startup script +will restore the volume after a reboot. If you find that your sound is +distorted, it's possible that the levels in the above examples are too high +for your particular hardware combination. Try reducing the percentages by +5-10% and checking again. Once you're satisfied, re-run the <CODE>alsactl +store</CODE> command.</P> +<P>You may also use the <B>alsamixer</B> program to set the volume. If you +are using an ALSA version after 1.0.6, use <B>alsamixer -V all</B> First, +start <B>alsamixer</B> from the command line. You should start out on the +"Master" volume control slider. Use the up and down cursor to set the +master volume to around 75%. Next, use the left and right cursor keys to +move around on the screen until you find the "Line" slider. Press SPACE to +set it as the capture source, set the level to around 50-75% and press "M" +to mute it. You can now press ESC to exit out of the <B>alsamixer</B> +program. You can also have MythTV manage all volume and mute settings, but +this will only affect the "Master" or PCM volume, not the capture volume. See +the mythfrontend setup page for options.</P> +<P>Finally, if you've performed all of the above steps, and you still don't seem to have any sound, it's possible that your video capture device is muting the audio output. +<BLOCKQUOTE><CODE> +<PRE> +$ v4lctl -c /dev/video0 setattr mute off +</PRE> +</CODE></BLOCKQUOTE> +</P> + +<HR> +<A HREF="mythtv-HOWTO-8.html">Next</A> +<A HREF="mythtv-HOWTO-6.html">Previous</A> +<A HREF="mythtv-HOWTO.html#toc7">Contents</A> +</BODY> +</HTML> |