xml/zh_CN/faq.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision: 34325 $ -->
<chapter id="faq" xreflabel="FAQ">
<title>Frequently Asked Questions</title>

<qandaset defaultlabel="qanda">

<qandadiv id="faq-development">
<title>Development</title>

<qandaentry>
<question><para>
How do I create a proper patch for <application>MPlayer</application>?
</para></question>
<answer><para>
We made a <ulink url="../../tech/patches.txt">short document</ulink>
describing all the necessary details. Please follow the instructions.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How do I translate <application>MPlayer</application> to a new language?
</para></question>
<answer><para>
Read the <ulink url="../../tech/translations.txt">translation HOWTO</ulink>,
it should explain everything. You can get further help on the
<ulink url="http://lists.mplayerhq.hu/mailman/listinfo/mplayer-translations">MPlayer-translations</ulink>
mailing list.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I support <application>MPlayer</application> development?
</para></question>
<answer><para>
We are more than happy to accept your hardware and software
<ulink url="http://www.mplayerhq.hu/donations.html">donations</ulink>.
They help us in continuously improving <application>MPlayer</application>.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I become an <application>MPlayer</application> developer?
</para></question>
<answer><para>
We always welcome coders and documenters. Read the
<ulink url="../../tech/">technical documentation</ulink>
to get a first grasp. Then you should subscribe to the
<ulink url="http://lists.mplayerhq.hu/mailman/listinfo/mplayer-dev-eng">MPlayer-dev-eng</ulink>
mailing list and start coding. If you want to help out with the documentation,
join the
<ulink url="http://lists.mplayerhq.hu/mailman/listinfo/mplayer-docs">MPlayer-docs</ulink>
mailing list.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
Why don't you use autoconf/automake?
</para></question>
<answer><para>
We have a modular, handwritten build system. It does a reasonably good
job, so why change? Besides, we dislike the auto* tools, just like
<ulink url="http://freshmeat.net/articles/view/889/">other people</ulink>.
</para></answer>
</qandaentry>
</qandadiv>

<!-- ********** -->

<qandadiv id="faq-compilation-installation">
<title>Compilation and installation</title>

<qandaentry>
<question><para>
Compilation fails with an error and <application>gcc</application> bails out
with some cryptic message containing the phrase
<systemitem>internal compiler error</systemitem> or
<systemitem>unable to find a register to spill</systemitem> or
<systemitem>can't find a register in class `GENERAL_REGS'
while reloading `asm'</systemitem>.
</para></question>
<answer><para>
You have stumbled over a bug in <application>gcc</application>. Please
<ulink url="http://gcc.gnu.org/bugs.html">report it to the gcc team</ulink>
but not to us. For some reason <application>MPlayer</application> seems to
trigger compiler bugs frequently. Nevertheless we cannot fix them and do not
add workarounds for compiler bugs to our sources. To avoid this problem,
either stick with a compiler version that is known to be reliable and
stable, or upgrade frequently.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
Are there binary (RPM/Debian) packages of <application>MPlayer</application>?
</para></question>
<answer><para>
See the <link linkend="debian">Debian</link> and <link linkend="rpm">RPM</link>
section for details.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I build a 32 bit <application>MPlayer</application> on a 64 bit Athlon?
</para></question>
<answer><para>
Try the following configure options:
<screen>
./configure --target=i386-linux --cc="gcc -m32" --as="as --32" --with-extralibdir=/usr/lib
</screen>
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
Configure ends with this text, and <application>MPlayer</application> won't compile!
<screen>Your gcc does not support even i386 for '-march' and '-mcpu'</screen>
</para></question>
<answer><para>
Your gcc isn't installed correctly, check the <filename>config.log</filename>
file for details.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I have a Matrox G200/G400/G450/G550, how do I compile/use the
<systemitem>mga_vid</systemitem> driver?
</para></question>
<answer><para>
Read the <link linkend="mga_vid">mga_vid</link> section.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
During 'make', <application>MPlayer</application> complains about
missing X11 libraries. I don't understand, I <emphasis>do</emphasis>
have X11 installed!?
</para></question>
<answer><para>
... but you don't have the X11 development package installed. Or not correctly.
It's called <filename>XFree86-devel*</filename> under Red Hat,
<filename>xlibs-dev</filename> under Debian Woody and
<filename>libx11-dev</filename> under Debian Sarge. Also check if the
<filename class="directory">/usr/X11</filename> and
<filename class="directory">/usr/include/X11</filename> symlinks exist.
</para></answer>
</qandaentry>
</qandadiv>

<!-- ********** -->

<qandadiv id="faq-general">
<title>General questions</title>

<qandaentry>
<question><para>
Are there any mailing lists on <application>MPlayer</application>?
</para></question>
<answer><para>
Yes. Look at the
<ulink url="http://www.mplayerhq.hu/design7/mailing_lists.html">mailing lists section</ulink>
of our homepage.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I've found a nasty bug when I tried to play my favorite video!
Who should I inform?
</para></question>
<answer><para>
Please read the <link linkend="bugreports">bug reporting guidelines</link>
and follow the instructions.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I get a core dump when trying to dump streams, what's wrong?
</para></question>
<answer><para>
Don't panic. Make sure you know where your towel is.</para>
<para>
Seriously, notice the smiley and start looking for files that end in
<filename>.dump</filename>.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
When I start playing, I get this message but everything seems fine:
<screen>Linux RTC init: ioctl (rtc_pie_on): Permission denied</screen>
</para></question>
<answer><para>
You need a specially set up kernel to use the RTC timing code.
For details see the <link linkend="rtc">RTC</link> section of the documentation.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I make a screenshot?
</para></question>
<answer><para>
You have to use a video output driver that does not employ an overlay to be
able to take a screenshot. Under X11, <option>-vo x11</option> will do, under
Windows <option>-vo directx:noaccel</option> works.
</para>
<para>
Alternatively you can run <application>MPlayer</application> with the
<systemitem>screenshot</systemitem> video filter
(<option>-vf screenshot</option>), and press the <keycap>s</keycap>
key to grab a screenshot.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
What is the meaning of the numbers on the status line?
</para></question>
<answer><para>
Example:
<screen>
A: 2.1 V: 2.2 A-V: -0.167 ct: 0.042 57/57 41% 0% 2.6% 0 4 49% 1.00x
</screen>
<variablelist>
<varlistentry>
  <term><systemitem>A: 2.1</systemitem></term>
  <listitem><para>audio position in seconds</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>V: 2.2</systemitem></term>
  <listitem><para>video position in seconds</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>A-V: -0.167</systemitem></term>
  <listitem><para>audio-video difference in seconds (delay)</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>ct: 0.042</systemitem></term>
  <listitem><para>total A-V sync correction done</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>57/57</systemitem></term>
  <listitem><para>
  frames played/decoded (counting from last seek)
  </para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>41%</systemitem></term>
  <listitem><para>
  video codec CPU usage in percent
  (for slice rendering and direct rendering this includes video_out)
  </para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>0%</systemitem></term>
  <listitem><para>video_out CPU usage</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>2.6%</systemitem></term>
  <listitem><para>audio codec CPU usage in percent</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>0</systemitem></term>
  <listitem><para>frames dropped to maintain A-V sync</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>4</systemitem></term>
  <listitem><para>
  current level of image postprocessing (when using <option>-autoq</option>)
  </para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>49%</systemitem></term>
  <listitem><para>
  current cache size used (around 50% is normal)
  </para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>1.00x</systemitem></term>
  <listitem><para>playback speed as a factor of original speed</para></listitem>
</varlistentry>
</variablelist>
Most of them are for debug purposes, use the <option>-quiet</option>
option to make them disappear.
You might notice that video_out CPU usage is zero (0%) for some files.
This is because it is called directly from the codec and thus cannot
be measured separately. If you wish to know the video_out speed, compare
the difference when playing the file with <option>-vo null</option> and
your usual video output driver.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
There are error messages about file not found
<filename>/usr/local/lib/codecs/</filename> ...
</para></question>
<answer><para>
Download and install the binary codecs from our
<ulink url="http://www.mplayerhq.hu/design7/dload.html">download page</ulink>.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I make <application>MPlayer</application> remember the options I
use for a particular file, e.g. <filename>movie.avi</filename>?
</para></question>
<answer><para>
Create a file named <filename>movie.avi.conf</filename> with the file-specific
options in it and put it in <filename class="directory">~/.mplayer</filename>
or in the same directory as the file.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
Subtitles are very nice, the most beautiful I've ever seen, but they
slow down playing! I know it's unlikely ...
</para></question>
<answer><para>
After running <filename>./configure</filename>,
edit <filename>config.h</filename> and replace
<systemitem>#undef FAST_OSD</systemitem> with
<systemitem>#define FAST_OSD</systemitem>. Then recompile.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I run <application>MPlayer</application> in the background?
</para></question>
<answer><para>
Use:
<screen>
mplayer <replaceable>options</replaceable> <replaceable>filename</replaceable> &lt; /dev/null &amp;
</screen>
</para></answer>
</qandaentry>
</qandadiv>

<!-- ********** -->

<qandadiv id="faq-playback">
<title>Playback problems</title>

<qandaentry>
<question><para>
I cannot pinpoint the cause of some strange playback problem.
</para></question>
<answer><para>
Do you have a stray <filename>codecs.conf</filename> file in
<filename>~/.mplayer/</filename>, <filename>/etc/</filename>,
<filename>/usr/local/etc/</filename> or a similar location? Remove it,
an outdated <filename>codecs.conf</filename> file can cause obscure
problems and is intended for use only by developers working on codec
support. It overrides <application>MPlayer</application>'s internal
codec settings, which will wreak havoc if incompatible changes are
made in newer program versions. Unless used by experts it is a recipe
for disaster in the form of seemingly random and very hard to localize
crashes and playback problems. If you still have it somewhere on your
system, you should remove it now.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I get subtitles to appear on the black margins around a movie?
</para></question>
<answer><para>
Use the <systemitem>expand</systemitem> video filter to increase the
area onto which the movie is rendered vertically and place the movie
at the top border, for example:
<screen>mplayer -vf expand=0:-100:0:0 -slang de dvd://1</screen>
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I select audio/subtitle tracks from a DVD, OGM, Matroska or NUT file?
</para></question>
<answer><para>
You have to use <option>-aid</option> (audio ID) or <option>-alang</option>
(audio language), <option>-sid</option>(subtitle ID) or <option>-slang</option>
(subtitle language), for example:
<screen>
mplayer -alang eng -slang eng <replaceable>example.mkv</replaceable>
mplayer -aid 1 -sid 1 <replaceable>example.mkv</replaceable>
</screen>
To see which ones are available:
<screen>
mplayer -vo null -ao null -frames 0 -v <replaceable>filename</replaceable> | grep sid
mplayer -vo null -ao null -frames 0 -v <replaceable>filename</replaceable> | grep aid
</screen>
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I'm trying to play a random stream off the internet but it fails.
</para></question>
<answer><para>
Try playing the stream with the <option>-playlist</option> option.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I downloaded a movie off a P2P network and it doesn't work!
</para></question>
<answer><para>
Your file is most probably broken or a fake file. If you got it from
a friend, and he says it works, try comparing
<application>md5sum</application> hashes.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I'm having trouble getting my subtitles to display, help!!
</para></question>
<answer><para>
Make sure you have installed fonts properly. Run through the steps in the
<link linkend="fonts-osd">Fonts and OSD</link> part of the installation
section again. If you are using TrueType fonts, verify that you have the
<systemitem class="library">FreeType</systemitem> library installed.
Other things include checking your subtitles in a text editor or with other
players. Also try converting them to another format.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
Why doesn't <application>MPlayer</application> work on Fedora Core?
</para></question>
<answer><para>
There is a bad interaction on Fedora between exec-shield,
prelink, and any applications which use Windows DLLs
(such as <application>MPlayer</application>).
</para>
<para>
The problem is that exec-shield randomizes the load addresses of all the
system libraries. This randomization happens at prelink time (once every
two weeks).
</para>
<para>
When <application>MPlayer</application> tries to load a Windows DLL it
wants to put it at a specific address (0x400000). If an important system
library happens to be there already, <application>MPlayer</application>
will crash.
(A typical symptom would be a segmentation fault when trying
to play Windows Media 9 files.)
</para>
<para>
If you run into this problem you have two options:
<itemizedlist>
<listitem><para>
  Wait two weeks. It might start working again.
</para></listitem>
<listitem><para>
  Relink all the binaries on the system with different
  prelink options. Here are step by step instructions:
  </para>
  <procedure>
  <step><para>
    Edit <filename>/etc/syconfig/prelink</filename> and change
    <programlisting>PRELINK_OPTS=-mR</programlisting> to
    <programlisting>PRELINK_OPTS="-mR --no-exec-shield"</programlisting>
  </para></step>
  <step><para>
    <command>touch /var/lib/misc/prelink.force</command>
  </para></step>
  <step><para>
    <command>/etc/cron.daily/prelink</command>
    (This relinks all the applications, and it takes quite a while.)
  </para></step>
  <step><para>
    <command>execstack -s <replaceable>/path/to/</replaceable>mplayer</command>
    (This turns off exec-shield for the
    <application>MPlayer</application> binary.)
  </para></step>
  </procedure>
</listitem>
</itemizedlist>
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
<application>MPlayer</application> dies with
<screen>MPlayer interrupted by signal 4 in module: decode_video</screen>
</para></question>
<answer><para>
Don't use <application>MPlayer</application> on a CPU different from the one
it was compiled on or recompile with runtime CPU detection
(<command>./configure --enable-runtime-cpudetection</command>).
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
When I try to grab from my tuner, it works, but colors are strange.
It's OK with other applications.
</para></question>
<answer><para>
Your card probably reports some colorspaces as supported when in fact
it does not support them. Try with YUY2 instead of the
default YV12 (see the <link linkend="tv-input">TV</link> section).
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I get very strange percentage values (way too big)
while playing files on my notebook.
</para></question>
<answer><para>
It's an effect of the power management / power saving system of your notebook
(BIOS, not kernel). Plug the external power connector in
<emphasis role="bold">before</emphasis> you power on your notebook. You can
also try whether
<ulink url="http://www.kernel.org/pub/linux/utils/kernel/cpufreq/cpufreq.html">cpufreq</ulink>
(a SpeedStep interface for Linux) helps you.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
The audio/video gets totally out of sync when I run
<application>MPlayer</application> as
<systemitem class="username">root</systemitem> on my notebook.
It works normal when i run it as a user.
</para></question>
<answer><para>
This is again a power management effect (see above). Plug the external power
connector in <emphasis role="bold">before</emphasis> you power on your notebook
or make sure you do not use the <option>-rtc</option> option.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
While playing a movie it suddenly gets jerky and I get the following message:
<screen>Badly interleaved AVI file detected - switching to -ni mode...</screen>
</para></question>
<answer><para>
Badly interleaved files and <option>-cache</option> don't work well together.
Try <option>-nocache</option>.
</para></answer>
</qandaentry>
</qandadiv>

<!-- ********** -->

<qandadiv id="faq-driver">
<title>Video/audio driver problems (vo/ao)</title>

<qandaentry>
<question><para>
When I go into fullscreen mode I just get black borders around the image
and no real scaling to fullscreen mode.
</para></question>
<answer><para>
Your video output driver does not support scaling in hardware and since
scaling in software can be incredibly slow <application>MPlayer</application>
does not automatically enable it. Most likely you are using the
<systemitem>x11</systemitem> instead of the <systemitem>xv</systemitem>
video output driver. Try adding <option>-vo xv</option> to the command
line or read the <link linkend="video">video section</link> to find out
about alternative video output drivers. The <option>-zoom</option>
option explicitly enables software scaling.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I've just installed <application>MPlayer</application>. When I want to
open a video file it causes a fatal error:
<screen>Error opening/initializing the selected video_out (-vo) device.</screen>
How can I solve my problem?
</para></question>
<answer><para>
Just change your video output device. Issue the following command to get
a list of available video output drivers:
<screen>mplayer -vo help</screen>
After you've chosen the correct video output driver, add it to
your configuration file. Add
<programlisting>
vo = <replaceable>selected_vo</replaceable>
</programlisting>
to <filename>~/.mplayer/config</filename> and/or
<programlisting>
vo_driver = <replaceable>selected_vo</replaceable>
</programlisting>
to <filename>~/.mplayer/gui.conf</filename>.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I have problems with <replaceable>[your window manager]</replaceable>
and fullscreen xv/xmga/sdl/x11 modes ...
</para></question>
<answer><para>
Read the <link linkend="bugreports">bug reporting guidelines</link> and send us
a proper bug report.
Also try experimenting with the <option>-fstype</option> option.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
Audio goes out of sync playing an AVI file.
</para></question>
<answer><para>
Try the <option>-bps</option> or <option>-nobps</option> option. If it does not
improve, read the
<link linkend="bugreports">bug reporting guidelines</link>
and upload the file to FTP.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I use <application>dmix</application> with
<application>MPlayer</application>?
</para></question>
<answer><para>
After setting up your
<ulink url="http://alsa.opensrc.org/index.php?page=DmixPlugin">asoundrc</ulink>
you have to use <option>-ao alsa:device=dmix</option>.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I have no sound when playing a video and get error messages similar to this one:
<screen>
AO: [oss] 44100Hz 2ch Signed 16-bit (Little-Endian)
[AO OSS] audio_setup: Can't open audio device /dev/dsp: Device or resource busy
Could not open/initialize audio device -> no sound.
Audio: no sound
Starting playback...
</screen>
</para></question>
<answer><para>
Are you running KDE or GNOME with the aRts or ESD sound daemon? Try disabling
the sound daemon or use the <option>-ao arts</option> or
<option>-ao esd</option> option to make <application>MPlayer</application> use
aRts or ESD.
You might also be running ALSA without OSS emulation, try loading the ALSA OSS
kernel modules or add <option>-ao alsa</option> to your command line to
directly use the ALSA audio output driver.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
When starting <application>MPlayer</application> under KDE I just get a black
screen and nothing happens. After about one minute the video starts playing.
</para></question>
<answer><para>
The KDE aRts sound daemon is blocking the sound device. Either wait until the
video starts or disable the aRts daemon in control center. If you want to use
aRts sound, specify audio output via our native aRts audio driver
(<option>-ao arts</option>). If it fails or isn't compiled in, try SDL
(<option>-ao sdl</option>) and make sure your SDL can handle aRts sound. Yet
another option is to start <application>MPlayer</application> with artsdsp.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I have A/V sync problems.
Some of my AVIs play fine, but some play with double speed!
</para></question>
<answer><para>
You have a buggy sound card/driver. Most likely it's fixed at 44100Hz, and you
try to play a file which has 22050Hz audio. Try the
<systemitem>resample</systemitem> audio filter.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
When I play this movie I get video-audio desync and/or
<application>MPlayer</application> crashes with the following message:
<screen>
Too many (945 in 8390980 bytes) video packets in the buffer!
</screen>
</para></question>
<answer><para>
This can have multiple reasons.
<itemizedlist>
<listitem><para>
  Your CPU <emphasis>and/or</emphasis> video card <emphasis>and/or</emphasis>
  bus is too slow. <application>MPlayer</application> displays a message if
  this is the case (and the dropped frames counter goes up fast).
</para></listitem>
<listitem><para>
  If it is an AVI, maybe it has bad interleaving, try the
  <option>-ni</option> option to work around this.
  Or it may have a bad header, in this case <option>-nobps</option>
  and/or <option>-mc 0</option> can help.
</para></listitem>
<listitem><para>
  Many FLV files will only play correctly with <option>-correct-pts</option>.
  Unfortunately <application>MEncoder</application> does not have this option,
  but you can try setting <option>-fps</option> to the correct value manually
  if you know it.
</para></listitem>
<listitem><para>
  Your sound driver is buggy.
</para></listitem>
</itemizedlist>
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I get rid of A/V desynchronization
while seeking through RealMedia streams?
</para></question>
<answer><para>
<option>-mc 0.1</option> can help.
</para></answer>
</qandaentry>
</qandadiv>

<!-- ********** -->

<qandadiv id="faq-dvd">
<title>DVD playback</title>

<qandaentry>
<question><para>
What about DVD navigation/menus?
</para></question>
<answer><para>
<application>MPlayer</application> should support DVD menus nowadays.
Your mileage may vary.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
What about subtitles? Can <application>MPlayer</application> display them?
</para></question>
<answer><para>
Yes. See the <link linkend="dvd">DVD chapter</link>.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I set the region code of my DVD-drive? I don't have Windows!
</para></question>
<answer><para>
Use the
<ulink url="http://linvdr.org/projects/regionset/">regionset tool</ulink>.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I can't play a DVD, MPlayer hangs or outputs "Encrypted VOB file!" errors.
</para></question>
<answer><para>
CSS decryption code does not work with some DVD drives unless you set
the region code appropriately. See the answer to the previous question.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
Do I need to be (setuid) root to be able to play a DVD?
</para></question>
<answer><para>
No. However you must have the proper rights
on the DVD device entry (in <filename class="directory">/dev/</filename>).
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
Is it possible to play/encode only selected chapters?
</para></question>
<answer><para>
Yes, try the <option>-chapter</option> option.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
My DVD playback is sluggish!
</para></question>
<answer><para>
Use the <option>-cache</option> option (described in the man page) and try
enabling DMA for the DVD drive with the <command>hdparm</command> tool.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I copied a DVD using vobcopy. How do I play/encode it from my hard disk?
</para></question>
<answer><para>
Use the <option>-dvd-device</option> option to refer to the directory
that contains the files:
<screen>
mplayer dvd://1 -dvd-device <replaceable>/path/to/directory</replaceable>
</screen>
</para></answer>
</qandaentry>
</qandadiv>


<qandadiv id="faq-features">
<title>Feature requests</title>

<qandaentry>
<question><para>
If <application>MPlayer</application> is paused and I try to seek or press any
key at all, <application>MPlayer</application> ceases to be paused.
I would like to be able to seek in the paused movie.
</para></question>
<answer><para>
This is very tricky to implement without losing A/V synchronization.
All attempts have failed so far, but patches are welcome.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I'd like to seek +/- 1 frame instead of 10 seconds.
</para></question>
<answer><para>
You can step forward one frame by pressing <keycap>.</keycap>.
If the movie was not paused it will be paused afterwards
(see the man page for details).
Stepping backwards is unlikely to be implemented anytime soon.
</para></answer>
</qandaentry>
</qandadiv>

<!-- ********** -->

<qandadiv id="faq-encoding">
<title>Encoding</title>

<qandaentry>
<question><para>
How can I encode?
</para></question>
<answer><para>
Read the <link linkend="mencoder"><application>MEncoder</application></link>
section.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I dump a full DVD title into a file?
</para></question>
<answer><para>
Once you have selected your title, and made sure it plays fine with
<application>MPlayer</application>, use the option <option>-dumpstream</option>.
For example:
<screen>
mplayer dvd://5 -dumpstream -dumpfile <replaceable>dvd_dump.vob</replaceable>
</screen>
will dump the 5th title of the DVD into the file
<replaceable>dvd_dump.vob</replaceable>
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I create (S)VCDs automatically?
</para></question>
<answer><para>
Try the <filename>mencvcd.sh</filename> script from the
<filename class="directory">TOOLS</filename> subdirectory.
With it you can encode DVDs or other movies to VCD or SVCD format
and even burn them directly to CD.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I create (S)VCDs?
</para></question>
<answer><para>
Newer versions of <application>MEncoder</application> can directly
generate MPEG-2 files that can be used as a base to create a VCD or SVCD and
are likely to be playable out of the box on all platforms (for example,
to share a video from a digital camcorder with your computer-illiterate
friends).
Please read
<link linkend="menc-feat-vcd-dvd">Using MEncoder to create VCD/SVCD/DVD-compliant files</link>
for more details.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I join two video files?
</para></question>
<answer><para>
MPEG files can be concatenated into a single file with luck.
For AVI files, you can use <application>MEncoder</application>'s
multiple file support like this:
<screen>
mencoder -ovc copy -oac copy -o <replaceable>out.avi</replaceable> <replaceable>file1.avi</replaceable> <replaceable>file2.avi</replaceable>
</screen>
This will only work if the files are of the same resolution
and use the same codec.
You can also try
<ulink url="http://fixounet.free.fr/avidemux/">avidemux</ulink> and
<application>avimerge</application> (part of the
<ulink url="http://www.transcoding.org/">transcode</ulink>
tool set).
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I fix AVI files with a broken index or bad interleaving?
</para></question>
<answer><para>
To avoid having to use <option>-idx</option> to be able to seek in
AVI files with a broken index or <option>-ni</option> to play AVI
files with bad interleaving, use the command
<screen>
mencoder <replaceable>input.avi</replaceable> -idx -ovc copy -oac copy -o <replaceable>output.avi</replaceable>
</screen>
to copy the video and audio streams into a new AVI file while
regenerating the index and correctly interleaving the data.
Of course this cannot fix possible bugs in the video and/or audio streams.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I fix the aspect ratio of an AVI file?
</para></question>
<answer><para>
You can do such a thing thanks to <application>MEncoder</application>'s
<option>-force-avi-aspect</option> option, which overrides the aspect
stored in the AVI OpenDML vprp header option. For example:
<screen>
mencoder <replaceable>input.avi</replaceable> -ovc copy -oac copy -o <replaceable>output.avi</replaceable> -force-avi-aspect 4/3
</screen>
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I backup and encode a VOB file with a broken beginning?
</para></question>
<answer><para>
The main problem when you want to encode a VOB file which is corrupted
<footnote id='fn-corrupted-files-or-copy-protection'><para>
To some extent, some forms of copy protection used in DVDs can be
assumed to be content corruption.
</para></footnote>
is that it will be hard to get an encode with perfect A/V sync.
One workaround is to just shave off the corrupted part and encode just the
clean part.
First you need to find where the clean part starts:
<screen>
mplayer <replaceable>input.vob</replaceable> -sb <replaceable>nb_of_bytes_to_skip</replaceable>
</screen>
Then you can create a new file which contains just the clean part:
<screen>
dd if=<replaceable>input.vob</replaceable> of=<replaceable>output_cut.vob</replaceable> skip=1 ibs=<replaceable>nb_of_bytes_to_skip</replaceable>
</screen>
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I can't encode DVD subtitles into the AVI!
</para></question>
<answer><para>
You have to properly specify the <option>-sid</option> option.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I encode only selected chapters from a DVD?
</para></question>
<answer><para>
Use the <option>-chapter</option> option correctly,
like: <option>-chapter 5-7</option>.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I'm trying to work with 2GB+ files on a VFAT file system. Does it work?
</para></question>
<answer><para>
No, VFAT doesn't support 2GB+ files.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
What is the meaning of the numbers on the status line
during the encoding process?
</para></question>
<answer><para>
Example:
<screen>
Pos: 264.5s   6612f ( 2%)  7.12fps Trem: 576min 2856mb  A-V:0.065 [2126:192]
</screen>
<variablelist>
  <varlistentry>
  <term><systemitem>Pos: 264.5s</systemitem></term>
  <listitem><para>time position in the encoded stream</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>6612f</systemitem></term>
  <listitem><para>number of video frames encoded</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>( 2%)</systemitem></term>
  <listitem><para>portion of the input stream encoded</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>7.12fps</systemitem></term>
  <listitem><para>encoding speed</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>Trem: 576min</systemitem></term>
  <listitem><para>estimated remaining encoding time</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>2856mb</systemitem></term>
  <listitem><para>estimated size of the final encode</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>A-V:0.065</systemitem></term>
  <listitem><para>current delay between audio and video streams</para></listitem>
</varlistentry>
<varlistentry>
  <term><systemitem>[2126:192]</systemitem></term>
  <listitem><para>
  average video bitrate (in kb/s) and average audio bitrate (in kb/s)
  </para></listitem>
</varlistentry>
</variablelist>
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
Why is the recommended bitrate printed by <application>MEncoder</application>
negative?
</para></question>
<answer><para>
Because the bitrate you encoded the audio with is too large to fit the
movie on any CD. Check if you have libmp3lame installed properly.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
I can't encode an ASF file to AVI/MPEG-4 (DivX) because it uses 1000 fps.
</para></question>
<answer><para>
Since ASF uses variable framerate but AVI uses a fixed one, you
have to set it by hand with the <option>-ofps</option> option.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I put subtitles in the output file?
</para></question>
<answer><para>
Just pass the <option>-sub &lt;filename&gt;</option> (or <option>-sid</option>,
respectively) option to <application>MEncoder</application>.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How do I encode only sound from a music video?
</para></question>
<answer><para>
It's not possible directly, but you can try this (note the
<emphasis role="bold">&amp;</emphasis> at the end of
<command>mplayer</command> command):
<screen>
mkfifo <replaceable>encode</replaceable>
mplayer -ao pcm -aofile <replaceable>encode</replaceable> dvd://1 &amp;
lame <replaceable>your_opts</replaceable> <replaceable>encode</replaceable> <replaceable>music.mp3</replaceable>
rm <replaceable>encode</replaceable>
</screen>
This allows you to use any encoder, not only <application>LAME</application>,
just replace <command>lame</command> with your favorite audio encoder in the
above command.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
Why do third-party players fail to play MPEG-4 movies encoded by
<application>MEncoder</application> versions later than 1.0pre7?
</para></question>
<answer><para>
<systemitem class="library">libavcodec</systemitem>, the native MPEG-4
encoding library usually shipped with <application>MEncoder</application>,
used to set the FourCC to 'DIVX' when encoding MPEG-4 videos
(the FourCC is an AVI tag to identify the software used to encode and
the intended software to use for decoding the video).
This led many people to think that
<systemitem class="library">libavcodec</systemitem>
was a DivX encoding library, when in fact it is a completely different
MPEG-4 encoding library which implements the MPEG-4 standard much
better than DivX does.
Therefore, the new default FourCC used by
<systemitem class="library">libavcodec</systemitem> is 'FMP4', but you
may override this behavior using <application>MEncoder</application>'s
<option>-ffourcc</option> option.
You may also change the FourCC of existing files in the same way:
<screen>
mencoder <replaceable>input.avi</replaceable> -o <replaceable>output.avi</replaceable> -ffourcc XVID
</screen>
Note that this will set the FourCC to XVID rather than DIVX.
This is recommended as DIVX FourCC means DivX4, which is a very basic
MPEG-4 codec, whereas DX50 and XVID both mean full MPEG-4 (ASP).
Therefore, if you change the FourCC to DIVX, some bad software or
hardware players may choke on some advanced features that
<systemitem class="library">libavcodec</systemitem> supports, but DivX
doesn't; on the other hand <systemitem class="library">Xvid</systemitem>
is closer to <systemitem class="library">libavcodec</systemitem> in
terms of functionality, and is supported by all decent players.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I encode an audio only file?
</para></question>
<answer><para>
Use <filename>aconvert.sh</filename> from the
<filename class="directory">TOOLS</filename>
subdirectory in the MPlayer source tree.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
How can I play subtitles embedded in AVI?
</para></question>
<answer><para>
Use <filename>avisubdump.c</filename> from the
<filename class="directory">TOOLS</filename> subdirectory or read
<ulink url="http://xlife.zuavra.net/curse/0012/">this document about extracting/demultiplexing subtitles embedded in OpenDML AVI files</ulink>.
</para></answer>
</qandaentry>

<qandaentry>
<question><para>
MEncoder won't...
</para></question>
<answer><para>
Have a look at the <filename class="directory">TOOLS</filename>
subdirectory for a collection of random scripts and hacks.
<filename>TOOLS/README</filename> contains documentation.
</para></answer>
</qandaentry>
</qandadiv>

</qandaset>

</chapter>