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<TITLE>Installing and using MythTV: Troubleshooting.</TITLE>
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<HR>
<H2><A NAME="s22">22.</A> <A HREF="mythtv-HOWTO.html#toc22">Troubleshooting.</A></H2>
<H2><A NAME="ss22.1">22.1</A> <A HREF="mythtv-HOWTO.html#toc22.1">Compiling</A>
</H2>
<H3>Compile errors</H3>
<P>Some compile errors are worse than others. If you get an error that
doesn't abort the compilation, and says something like:
<BLOCKQUOTE><CODE>
<PRE>
cc1plus: warning: changing search order for system directory
"/usr/local/include"
cc1plus: warning: as it has already been specified as a non-system
directory
</PRE>
</CODE></BLOCKQUOTE>
then it shouldn't be a problem.</P>
<P>If you get an error like <CODE>/usr/bin/ld: cannot find -lXext</CODE>, the
compiler is telling you that you don't have XFree86-devel installed, or that
your distribution hasn't set it up correctly. This needs to be fixed before
MythTV will compile.</P>
<H3><A NAME="mkspecs_error"></A> make: *** No rule to make target /usr/lib/qt3/mkspecs/default/qmake.conf', needed by Makefile'. Stop. </H3>
<P>This error happens when there's a missing link in the
<CODE>/usr/lib/qt3/mkspecs</CODE> directory. There are two ways to fix this
error:</P>
<P>1. Create the link manually:
<BLOCKQUOTE><CODE>
<PRE>
$ su
# cd /usr/lib/qt3/mkspecs
# ln -sf linux-g++ default
</PRE>
</CODE></BLOCKQUOTE>
and then restart the compile,</P>
<P>or</P>
<P>2. Run <B>qmake mythtv.pro</B> in the mythtv directory. Rerunning
<B>qmake</B> will create a new Makefile for you, however this still
doesn't fix the root cause of the issue, which is that your distribution
didn't create the symlink for you when the qt3 package was installed. The
first choice is the better solution.</P>
<H3>make: *** No rule to make target /mkspecs/default/qmake.conf', needed by Makefile'. Stop.</H3>
<P>You didn't set your <CODE>QTDIR</CODE>. Re-read the section on
<A HREF="mythtv-HOWTO-4.html#Setting_up_paths">Setting up paths</A>.</P>
<H3>Internal Segmentation Fault.</H3>
<P>This is most likely to be caused by an overheating processor rather than
an actual programming fault within gcc.</P>
<H2><A NAME="debugging"></A> <A NAME="ss22.2">22.2</A> <A HREF="mythtv-HOWTO.html#toc22.2">Debugging </A>
</H2>
<H3>MythTV segfaults</H3>
<H3>MythTV isn't doing anything</H3>
<H3>Debugging with GDB</H3>
<P>Without details, the developers will not be able to determine if you have
discovered a genuine code-bug, or if the problem is with your system. In
order to determine what's going on, you must recompile MythTV with debugging
support and run MythTV within <B>gdb</B>, the GNU debugger.
Note that, on OS X, some data is provided without going through these steps.
See /Library/Logs/CrashReporter/MythFrontend.crash.log</P>
<P>Re-run the <B>configure</B> script and add <CODE>--compile-type=debug</CODE>
to any previous configuration options you may have used. Check the
<CODE>config.log</CODE> file if you have forgotten.</P>
<P>Now, you need to clear out the old versions of the software to ensure that
you're running with the debugging code, then compile and install.
<BLOCKQUOTE><CODE>
<PRE>
$ make distclean
$ ./configure --compile-type=debug
$ make
$ su
# make install
# exit
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>At this point, you now have debug-enabled software ready. To make sure that
you don't forget to type a command required for debugging, it's best to
setup a <CODE>gdbcommands</CODE> file. This will be read by <B>gdb</B> when it's
started.
Put the following into <CODE>gdbcommands</CODE> in your home directory:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
handle SIGPIPE nostop noprint
handle SIG33 nostop noprint
set logging on
set pagination off
set args -l myth.log -v record,channel,siparser
run
thread apply all bt full
set logging off
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>Let's assume that the problem you're having is in <B>mythbackend</B>.</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
$ gdb mythbackend -x gdbcommands
GNU gdb 6.3-debian
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i386-linux".Using host libthread_db library "/lib/tls/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P><B>gdb</B> will automatically read the commands that you've placed in the
<CODE>gdbcommands</CODE> file and begin running the program you specified on the
command line.</P>
<P>If the program appears to be locked up, press CTRL-C to create the backtrace
file.</P>
<P>All of the output from <CODE>gdb.txt</CODE> should be posted to the mythtv-dev
mailing list, along with the steps you followed to get the program to crash.</P>
<P><B>NOTE</B>: If you're trimming the <CODE>gdb.txt</CODE> file to remove
extraneous information from the beginning of the file, make sure you include
at least 10 lines <EM>prior</EM> to the point where the backtrace actually
begins. This ensures that there is some context to the backtrace, and so
that it's possible to see what exactly caused the segfault.</P>
<P><B>gdb</B> has a number of options, read the <CODE>man</CODE> page for more
information. </P>
<P>Using the <CODE>gdbcommands</CODE> file in conjunction with a <B>while</B> loop
will ensure that <B>gdb</B> creates a trace file and then restarts:</P>
<P>
<BLOCKQUOTE><CODE>
<PRE>
$ while true; do date >> gdb.txt; gdb mythbackend -x gdbcommands; done;
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P><B>NOTE</B>: To exit this loop you will need to kill the while loop.</P>
<P>If you're trying to troubleshoot and you can't get back to the <B>gdb</B> window
for some reason, it may be easier to use two systems or to start
mythfrontend from the text console.</P>
<P>If you're going to troubleshoot from a remote system, connect to the machine
that you're going to test using <B>ssh</B> or <B>telnet</B>. Next, type
<CODE>$ export DISPLAY=localhost:0.0</CODE>. This will allow the graphics to be
displayed on the X console (usually ALT-F6 or ALT-F7) and still give you
output and control of <B>mythfrontend</B>, either from the <B>ssh</B>
session, or by switching back to the text console by pressing CTRL-ALT-F1.
You can now continue troubleshooting using <B>gdb</B> as detailed in the
instructions.</P>
<H3>MythTV is crashing your system</H3>
<P>When run as a non-privileged user, MythTV <EM>can not</EM> crash your
system. If your system is crashing when you run MythTV, then you have some
issue with the drivers for your capture card or other hardware, or the CPU
fan has fallen off/broken and your system is overheating when asked to
perform a CPU intensive task like encoding video.</P>
<P>If you are running as root, which is <B>strongly discouraged</B>, it is
possible that your system may crash due to the real-time thread using all
available CPU. You will not be able to interrupt the process, so for all
intents and purposes your computer will have crashed.</P>
<H2><A NAME="ss22.3">22.3</A> <A HREF="mythtv-HOWTO.html#toc22.3">Installing</A>
</H2>
<H3>When trying to run mythtv-setup, you get an error like this: "mythtv-setup: error while loading shared libraries:"</H3>
<P>You didn't add <CODE>/usr/local/lib</CODE> to <CODE>/etc/ld.so.conf</CODE>. See the
section on modifying
<A HREF="mythtv-HOWTO-4.html#modifying_ld.so.conf">/etc/ld.so.conf</A>.</P>
<H2><A NAME="ss22.4">22.4</A> <A HREF="mythtv-HOWTO.html#toc22.4">Using</A>
</H2>
<H3>No programs are displayed in "Watch Recordings"</H3>
<P>This situation occurs most often with a system that acts as a frontend
and a slave backend. MythTV supports system-global and user-specific
configuration files, with user-configuration files taking precedence. 99%
of the configuration for MythTV is in the MySQL database, but MythTV still
needs to know where the MySQL server is running. This information is in the
<CODE>mysql.txt</CODE> file. By default, it will be installed to
<CODE>/usr/local/share/mythtv</CODE>, but a copy placed into <CODE>~/.mythtv</CODE>
will over-ride the global configuration.</P>
<P>You must ensure that there aren't multiple, conflicting versions of this
file on your system!
<BLOCKQUOTE><CODE>
<PRE>
$ locate mysql.txt
/usr/local/share/mythtv/mysql.txt
/home/mythtv/.mythtv/mysql.txt
$
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>As you can see, in this example there are two <CODE>mysql.txt</CODE> files. If
they are not identical, then there may be unintended consequences.</P>
<P>You may also see this error if you completely fill the <CODE>/var</CODE>
partition. The most likely <EM>mythtv-related</EM> reason for this is an
overly large mythbackend or mythfrontend log file in <CODE>/var/log</CODE>. If
you have logging enabled for the backend, and myth runs for weeks at a time,
this may creep up and surprise you. Note that many system processes also
write to <CODE>/var</CODE> and the system may not boot if it is unable to write
to <CODE>/var</CODE> due to a full partition.</P>
<H3>MySQL not connecting correctly</H3>
<P>Your <B>MySQL</B> installation may have networking turned off.
Check that <CODE>/etc/mysql/my.cnf</CODE> <EM>does not</EM> contain
<CODE>skip-networking</CODE>. If it does, remove it. Also verify that
<CODE>bind-address</CODE> is set to your IP address instead of
<CODE>127.0.0.1</CODE>. If you change either of these items, restart
<B>MySQL</B>.</P>
<H3>MySQL database is corrupt</H3>
<P>If you have reason to believe that your MySQL database is corrupt,
execute the following commands to attempt to repair it.</P>
<P><B>NOTE</B>: Ensure that there are no programs accessing the database
while you attempt to repair it. Make sure that all backend and frontend
programs have exited.</P>
<P><CODE>mysqlcheck -r -umythtv -p<password> mythconverg</CODE></P>
<H3>Using a MPEG-2 encoder card and the video appears "jittery"</H3>
<H3>Using a MPEG-2 encoder card and the video is jumping up and down</H3>
<P>This is a different problem than the one discussed in the previous
section. Currently, the ivtv driver or firmware appear to have some issues
if the vertical capture resolution is not the full screen height. If you
are having a jitter problem then ensure that you are capturing either 480
lines (for NTSC) or 576 lines (for PAL). The default capture profiles may
need to be edited for your setup. Go to Settings->TV Settings->Recording
Profiles and adjust the <B>Default</B> and <B>Live TV</B> options to
480 or 576 from their defaults.</P>
<H3>Screen goes blank but returns when mouse is moved or keyboard is used</H3>
<P>This is due to DPMS, the Display Power Management System, which is used
to save power by turning off your monitor when the system decides that it's
not being used or due to a screensaver that has defaulted to a blank screen.
MythTV now has DPMS support built-in, and should intelligently handle the
screen. Continue reading if you wish to override DPMS and force it off.</P>
<P>Since it's likely that watching TV will not generate keyboard or mouse
events for a time, you need to turn off DPMS and the screensaver. There are
a few ways to do this. You may also need to check your BIOS for power
saving modes and disable screen blanking there as well.</P>
<P>Edit your <CODE>/etc/X11/XF86Config-4</CODE> or <CODE>/etc/X11/xorg.conf</CODE>
file, and look for:
<BLOCKQUOTE><CODE>
<PRE>
Section "ServerFlags"
#DontZap # disable <Ctrl><Alt><BS> (server abort)
#DontZoom # disable <Ctrl><Alt><KP_+>/<KP_-> (resolution switching)
AllowMouseOpenFail # allows the server to start up even if the mouse doesn't work
Option "blank time" "0"
Option "standby time" "0"
Option "suspend time" "0"
Option "off time" "0"
Option "NoPM" "1"
EndSection
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>Also, look for:
<BLOCKQUOTE><CODE>
<PRE>
Section "Device"
Identifier "device1"
VendorName "nVidia Corporation"
BoardName "NVIDIA GeForce 256 (generic)"
Driver "nv"
Option "DPMS"
EndSection
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>In this case, you would need to either delete the <CODE>Option "DPMS"</CODE>
line, or change it to <CODE># Option "DPMS"</CODE> to comment it out. The next
time you start XFree this change will take effect.</P>
<P>Finally, check:
<BLOCKQUOTE><CODE>
<PRE>
Section "Monitor"
Identifier "monitor1"
VendorName "Plug'n Play"
HorizSync 30-85
VertRefresh 50-160
# Sony Vaio C1(X,XS,VE,VN)?
# 1024x480 @ 85.6 Hz, 48 kHz hsync
ModeLine "1024x480" 65.00 1024 1032 1176 1344 480 488 494 563 -hsync -vsync
# TV fullscreen mode or DVD fullscreen output.
# 768x576 @ 79 Hz, 50 kHz hsync
ModeLine "768x576" 50.00 768 832 846 1000 576 590 595 630
# 768x576 @ 100 Hz, 61.6 kHz hsync
ModeLine "768x576" 63.07 768 800 960 1024 576 578 590 616
EndSection
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>Ensure that there isn't an <CODE>Option "DPMS"</CODE> in the Monitor
configuration.</P>
<P>You can also turn off DPMS from the Command Line, but this will not survive
a reboot.
<BLOCKQUOTE><CODE>
<PRE>
$ xset -dpms
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>Using <CODE>xset +dpms</CODE> will turn it back on.</P>
<P>Another technique to try, which will turn off the screensaver:
<BLOCKQUOTE><CODE>
<PRE>
$ xset s off
</PRE>
</CODE></BLOCKQUOTE>
You may also combine the command to turn off DPMS and the screensaver:
<BLOCKQUOTE><CODE>
<PRE>
$ xset -dpms s off
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>Finally, depending on your distribution, you may be able to turn it off from
within the control panel.</P>
<H2><A NAME="ss22.5">22.5</A> <A HREF="mythtv-HOWTO.html#toc22.5">Miscellaneous</A>
</H2>
<H3>mythfilldatabase failing</H3>
<P>If mythfilldatabase suddenly appears to be failing, there are at least
two things to check. </P>
<P>First, if you are in North America, ensure that your DataDirect subscription
is still valid, otherwise, check to see what version of XMLTV you're
running and that it's the latest version.</P>
<P>
<FIGURE>
<EPS FILE="stop.eps">
<IMG SRC="stop.png">
<CAPTION><B>NOTE</B>: It is highly recommended that you run the latest
version of XMLTV available. Your listings provider may have made changes
which negatively impact XMLTV.</CAPTION>
</FIGURE>
</P>
<H3><A NAME="Setting_DMA"></A> Fast CPU, choppy or jittery video </H3>
<P>First, you should check that your kernel has been enabled for DMA:
<BLOCKQUOTE><CODE>
<PRE>
[mythtv@pvr mythtv]$ dmesg |grep DMA
ide0: BM-DMA at 0xd800-0xd807, BIOS settings: hda:DMA, hdb:DMA
ide1: BM-DMA at 0xd808-0xd80f, BIOS settings: hdc:DMA, hdd:pio
hda: 156301488 sectors (80026 MB) w/2048KiB Cache, CHS=9729/255/63, UDMA(33)
hdb: 80043264 sectors (40982 MB) w/2048KiB Cache, CHS=4982/255/63, UDMA(33)
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>From the listing above, you can see that hda, hdb and hdc are set for DMA,
and hdd is set for pio. If your kernel is not reporting DMA being enabled,
you may need to recompile your kernel. Check your motherboard's chipset
(look in the "ATA/IDE/MFM/RLL support" section in "make menuconfig") for more
information.</P>
<P>Next, check that the hard drive has DMA enabled. Use the <B>hdparm</B>
program to check and enable DMA.
<BLOCKQUOTE><CODE>
<PRE>
# hdparm -d /dev/hd?
</PRE>
</CODE></BLOCKQUOTE>
will tell you the DMA status for your hard drives. If you run
<B>hdparm</B> with the <CODE>-d1</CODE> parameter, it will turn DMA on.</P>
<P>You may also setup your PC to do this at boot time, either by adding the
command to your <CODE>/etc/rc.local</CODE> file, or by adding files to
/etc/sysconfig.</P>
<P>On Mandriva and other distributions, if you install <B>hdparm</B> from an RPM you
will most likely get a <CODE>/etc/sysconfig/harddisks</CODE> file installed.
This file will be parsed by the <CODE>/etc/rc.sysinit</CODE> script. If you use
the default <CODE>harddisks</CODE> file, your changes will affect all IDE devices
(including CD ROMs). If you wish to use different parameters for various
devices, rename and/or copy the file to <CODE>harddiskhda</CODE>,
<CODE>harddiskhdb</CODE>, etc. Edit the file to your liking and on the next
reboot your setting will be preserved.</P>
<H3>Frontend appears to be slow at jumping / seeking.</H3>
<H3>On-screen Display shows incorrect program length.</H3>
<P>This may occur when MythTV doesn't have an accurate seek table. Run
<B>mythcommflag --rebuild</B></P>
<H3><A NAME="Troubleshooting_Audio"></A> Troubleshooting audio </H3>
<P>
<FIGURE>
<EPS FILE="stop.eps">
<IMG SRC="stop.png">
<CAPTION><B>NOTE</B>: the following instructions do not apply to PVR-250/350
encoders; the MPEG-2 file will have the audio embedded in the stream so it
is not accessible using <CODE>/dev/dsp</CODE>. </CAPTION>
</FIGURE>
</P>
<P>Audio appears to be one of the bigger issues that users run into on the
mailing list. If the audio isn't configured correctly, then MythTV will
often appear to hang, when in fact it is trying to manipulate the audio
subsystem and failing. You may or may not receive error messages indicating
that the source of the error is the audio subsystem.</P>
<P>You can not use <B>xawtv</B> to determine if your audio is working
correctly, since <B>xawtv</B> is simply using the analog sound patched
through line-in to line-out. It doesn't need to digitize the sound unless
you are using the recording function.</P>
<P>A better test to verify that sound will work for MythTV (and recording with
<B>xawtv</B> for that matter) is to startup <B>xawtv</B>, mute the
line-in then run <CODE>aplay /dev/dsp</CODE>. You should hear the recorded audio
slightly delayed behind the real-time video. You should see messages about
"underrun". These can be ignored but they do confirm that the driver is
loaded and there is an active device. Once this test succeeds, MythTV
should work correctly because it writes to and read from /dev/dsp in
the same way that <B>aplay</B> does.</P>
<P>To record audio along with video the audio signal must be digitized by a DSP
so that the audio data can be stored in a file. On playback, the audio data
is written to /dev/dsp and converted back to an analog signal. This analog
signal should then be sent to your speakers. Here is what is needed in
<B>alsamixer</B>. If you are using an ALSA version after 1.0.6, use
<B>alsamixer -V all</B>:</P>
<P>CAPTUR source - the analog source to be sent to the DSP. This should be set
to the input source from the tuner card to the sound card. In most cases
this is Line but this could also be Aux, CD, Mic, etc., depending on how you
connect the input cable. This source should be muted to prevent patching
through the analog sound. The volume of this source will not affect the
record level.</P>
<P>Capture mixer - this sets the level for the analog to digital recording.
While a volume of 100% is recommended for testing, distortion may occur.
Lowering this level to 75% to 85% may result in better audio quality.
"Capture" should be marked as the CAPTUR destination.</P>
<P>PCM mixer - this sets the level for the digital to analog playback. While a
volume of 100% is recommended for testing, distortion may occur. Lowering
this level to 75% to 85% may result in better audio quality.</P>
<P>Master mixer - sets the level for the analog signal sent to line-out or the
speakers.</P>
<P>You may also want to ensure that <CODE>/dev/dsp</CODE> , or whatever device file
is being used, hasn't already been grabbed by another process, like
<B>esd</B> or <B>artsd</B>. If the device file isn't available, then
MythTV won't work. You may wish to run <B>configure</B> and enable
support for these.</P>
<P>If you wish to see what application is grabbing a resource, you can use the
<CODE>fuser</CODE> command:
<BLOCKQUOTE><CODE>
<PRE>
# fuser -v /dev/dsp
</PRE>
</CODE></BLOCKQUOTE>
</P>
<P>To disable aRts in KDE, go to KDE->Control Center->Sound->Sound System and
uncheck the "Start aRts soundserver on KDE startup" box. Run <CODE># killall
artsd</CODE> from the command line to stop the artsd program.</P>
<P>If you're using multiple sound cards and multiple tuners, use <CODE>alsamixer
-c 1</CODE> to work with the second sound card. The first card is #0, the
second card is #1, etc.</P>
<H3>Mythbackend reports that your card is not reporting full duplex capabilities</H3>
<H3>The mythbackend program told me to look at this section</H3>
<P>mythbackend does a check to see if your sound device is capable of full
duplex operation. If it's not, it's most likely that you're going to run
into issues when you try to record and play sound at the same time. If your
backend is a separate machine than your frontend, then there's no problem,
since you're only going to be doing one thing at a time with the card.
Likewise, if you're running the frontend and backend on the same machine,
but you're using btaudio or a hardware encoder card such as the Hauppauge
PVR-250, DVB cards or HDTV capture cards as your recording source and you're
only using the playback function of your sound card, then you also shouldn't
have an issue, since the sound card isn't being asked to perform two
functions at once.</P>
<P>If you can't get your sound card to go full-duplex and need it to, then check
your distribution for updated sound drivers. If your sound card is not
capable of full-duplex operation, either because the drivers don't support
it, or it has been designed that way, then you're pretty much out of luck
and will either need to purchase a new sound card, or will need to get
btaudio
<A HREF="mythtv-HOWTO-23.html#btaudio">operational</A>.</P>
<H3>My remote doesn't work / works sometimes and not others / "ghost" keypresses</H3>
<P>This can be due to a number of factors. The simplest case is the
"ghost" keypresses. For me, it was due to compact fluorescent lights in
the same room as the IR receiver, which the receiver was picking up as
keypresses. Once the lights were switched to incandescent bulbs, the ghost
went away.</P>
<P>You may have an issue with <B>lirc</B> misinterpreting IR commands from a
different remote. I also have an issue where the TiVo "Peanut" remote will
eventually cause <B>lircd</B> to stop responding; even though <B>lircd</B>
is configured for the Pinnacle Systems remote, the TiVo remote IR patterns
are being seen by the IR receiver.</P>
<P>If your remote has been properly configured, and <B>irw</B> and
<B>irxevent</B> are working correctly, then it's highly likely that your
window manager is not giving focus correctly to the various Myth programs as
they run. The following window managers are known to work correctly:</P>
<P>
<UL>
<LI>fvwm</LI>
<LI>blackbox (using "Sloppy Focus" and "Focus New Windows")</LI>
</UL>
</P>
<P><B>NOTE</B>: You do not need to use <B>irxevent</B> if you are using
MythTV's native LIRC support, so the window manager focus issue does not
apply in that case.</P>
<H3>Where's "canada-cable"?</H3>
<H3>Channels are off by one</H3>
<P>There is no such thing as "Canada Cable"; Canada uses the same
frequencies as the United States. "Canada Cable" was a hack that some
people used when they would discover that their channels were off-by-one,
i.e. when tuning to channel 42, they might get channel 41 or 43. This is
actually due to the tuner on the video capture device being mis-detected.
You must manually specify the tuner type in your <CODE>/etc/modules.conf</CODE>.
See the video4linux mailing list (
<A HREF="https://listman.redhat.com/mailman/listinfo/video4linux-list">https://listman.redhat.com/mailman/listinfo/video4linux-list</A>) for
more information.</P>
<H3>Mythweb is showing a db_open error when I connect to it</H3>
<P>Find your <CODE>php.ini</CODE> file. Make sure you've got a line in it like this:</P>
<P><CODE>extension=mysql.so</CODE></P>
<P>Restart <B>apache</B> for it to take effect.</P>
<H3>Mouse pointer disappears when placed over the MythTV windows</H3>
<P>This is the intended behavior. The MythTV interface is meant for use
with a remote control or a keyboard.</P>
<H3>What does "strange error flushing buffer" mean on the console?</H3>
<P>Nothing, really. It's just lame (the mp3 encoder) complaining for some
obscure reason. This seems to be fixed in more recent versions of the
libmp3lame library.</P>
<H3>Can't change the channel when watching Live TV.</H3>
<P>Something's wrong with your program database. Did mythfilldatabase run
with no major errors? Or, MythTV may not have permissions to the
appropriate video4linux devices. See the section titled
<A HREF="mythtv-HOWTO-4.html#devperms">Device Permissions</A> for an example.</P>
<H3>Screen goes black when you try to play something</H3>
<P>MythTV prints error and status messages to the shell that was used to
start the application. If nothing seems to be happening when you try to
view a program, try switching back to the shell and look for error messages
there, or, if you're running from a startup script, check the log file.</P>
<H3>Poor performance with NVidia cards and XvMC</H3>
<P>XvMC is a NVidia driver feature which is supposed to help with decoding
video. Users have reported that rather than speeding up their video it
appears to be doing the opposite. You may want to check that your color
depth is set for 24bpp.</P>
<H3>Computer is loading a media player application when you insert a CD or DVD</H3>
<P>You need to disable any sort of auto-running media player in your
environment, otherwise MythDVD or MythMusic will not be able to work
properly.</P>
<P>In KDE, you may want to perform the following:
<BLOCKQUOTE><CODE>
<PRE>
$ rm ~/.kde/Autostart/Autorun.desktop
</PRE>
</CODE></BLOCKQUOTE>
</P>
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