path: root/DOCS/xml/en/codecs.xml

<?xml version="1.0" encoding="utf-8"?>
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<chapter id="codecs">
<title>Codecs</title>

<para>
The <ulink url="../../codecs-status.html">codec status table</ulink> is a
complete list of all supported codecs, regenerated daily.
Some binary codecs for use with MPlayer are available in the
<ulink url="http://www.mplayerhq.hu/design7/dload.html#binary_codecs">download section</ulink>
of our homepage.
</para>

<para>
If you have a Win32 codec which is not supported yet,
please read the <link linkend="codec-importing">codec importing HOWTO</link>
and help us add support for it.
</para>


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<sect1 id="audio-codecs">
<title>Audio codecs</title>


<sect2 id="swac3">
<title>Software AC-3 decoding</title>

<para>
This is the default decoder used for files with AC-3 audio.
</para>

<para>
The AC-3 decoder can create audio output mixes for 2, 4, or 6 speakers.
When configured for 6 speakers, this decoder provides separate output of
all the AC-3 channels to the sound driver, allowing for full "surround
sound" experience without the external AC-3 decoder required to use the
hwac3 codec.
</para>

<para>
Use the <option>-channels</option> option to select the number of output
channels.  Use <option>-channels 2</option> for a stereo downmix.  For a 4
channel downmix (Left Front, Right Front, Left Surround and Right Surround
outputs), use <option>-channels 4</option>.  In this case, any center
channel will be mixed equally to the front channels.
<option>-channels 6</option> will output all the AC-3 channels as they are
encoded - in the order Left, Right, Left Surround, Right Surround, Center and
LFE.
</para>

<para>
The default number of output channels is 2.
</para>

<para>
To use more than 2 output channels, you will need to use OSS, and have a
sound card that supports the appropriate number of output channels via the
SNDCTL_DSP_CHANNELS ioctl.  An example of a suitable driver is emu10k1
(used by Soundblaster Live! cards) from August 2001 or newer (ALSA CVS is
also supposed to work).
</para>
</sect2>

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<sect2 id="hwac3">
<title>Hardware AC-3 decoding</title>

<para>
You need an AC-3 capable sound card, with digital out (S/PDIF). The card's
driver must properly support the AFMT_AC3 format (C-Media does).  Connect
your AC-3 decoder to the S/PDIF output, and use the <option>-ac
hwac3</option> option. It is experimental but known to work with C-Media
cards and Soundblaster Live! + ALSA (but not OSS) drivers and DXR3/Hollywood+
MPEG decoder cards.
</para>
</sect2>

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<sect2 id="hwmpa">
<title>Hardware MPEG audio codec</title>

<para>
This codec (selected by <option>-ac hwmpa</option>) passes through MPEG audio
packets to hardware decoders, such as the ones found in full-featured DVB cards 
and DXR2 adapters.
Don't use it in combination with any other audio output device
(such as OSS and ALSA) that isn't able to decode it (you will hear
only white noise).
</para>
</sect2>

</sect1>


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<sect1 id="codec-importing">
<title>Win32 codecs importing HOWTO</title>

<!-- TODO: a short paragraph of text would be nice here... -->

<sect2 id="vfw-codecs">
<title>VFW codecs</title>

<para>
VFW (Video for Windows) is the old Video API for Windows. Its codecs have
the <filename>.DLL</filename> or (rarely) <filename>.DRV</filename>
extension.  If <application>MPlayer</application> fails at playing your AVI
with this kind of message:
<screen>UNKNOWN video codec: HFYU (0x55594648)</screen>
It means your AVI is encoded with a codec which has the HFYU fourcc (HFYU =
HuffYUV codec, DIV3 = DivX Low Motion, etc.). Now that you know this, you
have to find out which DLL Windows loads in order to play this file. In our
case, the <filename>system.ini</filename> contains this information in a
line that reads:
<programlisting>VIDC.HFYU=huffyuv.dll</programlisting>
</para>

<para>
So you need the <filename>huffyuv.dll</filename> file. Note that the audio
codecs are specified by the MSACM prefix:
<programlisting>msacm.l3acm=L3codeca.acm</programlisting>
</para>

<para>
This is the MP3 codec.  Now that you have all the necessary information
(fourcc, codec file, sample AVI), submit your codec support request by
mail, and upload these files to the FTP site:
<systemitem role="url">ftp://upload.mplayerhq.hu/MPlayer/incoming/<replaceable>&lt;codecname&gt;</replaceable>/</systemitem>
</para>

<note><para>
On Windows NT/2000/XP search for this info in the registry,
e.g. search for "VIDC.HFYU". To find out how to do this, look at
the old DirectShow method below.
</para></note>
</sect2>

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<sect2 id="dshow-codecs">
<title>DirectShow codecs</title>

<para>
DirectShow is the newer Video API, which is even worse than its predecessor.
Things are harder with DirectShow, since
<itemizedlist>
<listitem><para>
  <filename>system.ini</filename> does not contain the needed information,
  instead it is stored in the registry and
</para></listitem>
<listitem><para>
  we need the GUID of the codec.
</para></listitem>
</itemizedlist>
</para>

<procedure>
<title>New Method:</title>
<para>
Using <application>Microsoft GraphEdit</application> (fast)
</para>
<step><para>
  Get <application>GraphEdit</application> from either DirectX SDK or
  <ulink url="http://doom9.net">doom9</ulink>.
</para></step>
<step><para>
  Start <command>graphedit.exe</command>.
</para></step>
<step><para>
  From the menu select
  <menuchoice><guimenu>Graph</guimenu>
  <guisubmenu>Insert Filters</guisubmenu></menuchoice>.
</para></step>
<step><para>
  Expand item <systemitem>DirectShow Filters</systemitem>.
</para></step>
<step><para>
  Select the right codec name and expand item.
</para></step>
<step><para>
  In the entry <systemitem>DisplayName</systemitem> look at the text in
  winged brackets after the backslash and write it down (five dash-delimited
  blocks, the GUID).
</para></step>
<step><para>
  The codec binary is the file specified in the
  <systemitem>Filename</systemitem> entry.
</para></step>
</procedure>

<note><para>
If there is no <systemitem>Filename</systemitem> and
<systemitem>DisplayName</systemitem> contains something like
<systemitem>device:dmo</systemitem>, then it is a DMO-Codec.
</para></note>

<procedure>
<title>Old Method:</title>
<para>
Take a deep breath and start searching the registry...
</para>
<step><para>
  Start <command>regedit</command>.
</para></step>
<step><para>
  Press <keycombo><keycap>Ctrl</keycap><keycap>F</keycap></keycombo>, disable
  the first two checkboxes, and enable the third. Type in the fourcc of the
  codec (e.g. <userinput>TM20</userinput>).
</para></step>
<step><para>
  You should see a field which contains the path and the filename (e.g.
  <filename>C:\WINDOWS\SYSTEM\TM20DEC.AX</filename>).
</para></step>
<step><para>
  Now that you have the file, we need the GUID. Try searching again, but
  now search for the codec's name, not the fourcc. Its name can be acquired
  when Media Player is playing the file, by checking
  <menuchoice><guimenu>File</guimenu> <guisubmenu>Properties</guisubmenu>
  <guimenuitem>Advanced</guimenuitem></menuchoice>.
  If not, you are out of luck. Try guessing (e.g. search for TrueMotion).
</para></step>
<step><para>
  If the GUID is found you should see a <guilabel>FriendlyName</guilabel>
  and a <guilabel>CLSID</guilabel> field. Write down the 16 byte CLSID,
  this is the GUID we need.
</para></step>
</procedure>

<note><para>
If searching fails, try enabling all the checkboxes. You may have
false hits, but you may get lucky...
</para></note>

<para>
Now that you have all the necessary information (fourcc, GUID, codec file,
sample AVI), submit your codec support request by mail, and upload these files
to the FTP site:
<systemitem role="url">ftp://upload.mplayerhq.hu/MPlayer/incoming/<replaceable>&lt;codecname&gt;</replaceable>/</systemitem>
</para>

<para>
If you want to add a codec yourself, read
<ulink url="http://www.mplayerhq.hu/MPlayer/DOCS/tech/codecs.conf.txt">DOCS/tech/codecs.conf.txt</ulink>.
</para>

</sect2>
</sect1>

</chapter>