</p></li><li><p>
  </p><pre class="screen">make &amp;&amp; make install</pre><p>
</p></li><li><p>
  If you specified <tt class="option">--enable-divxcompat</tt>,
  copy <tt class="filename">../../src/divx4.h</tt> to
  <tt class="filename">/usr/local/include/</tt>.
</p></li><li><p>
  Recompile <span class="application">MPlayer</span> with
  <tt class="option">--with-xvidlibdir=<em class="replaceable"><code>/path/to/</code></em>libxvidcore.a</tt>
  <tt class="option">--with-xvidincdir=<em class="replaceable"><code>/path/to/</code></em>xvid.h</tt>.
</p></li></ol></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="codec-x264"></a>7.1.3.聽<code class="systemitem">x264</code></h3></div></div></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="codec-x264-whatis"></a>7.1.3.1.聽What is <code class="systemitem">x264</code>?</h4></div></div></div><p>
<a class="ulink" href="http://developers.videolan.org/x264.html" target="_top"><code class="systemitem">x264</code></a>
is a library for creating H.264 video streams.
It is not 100% complete, but currently it has at least some kind
of support for most of the H.264 features which impact quality.
There are also many advanced features in the H.264 specification
which have nothing to do with video quality per se; many of these
are not yet implemented in <code class="systemitem">x264</code>.
</p><div class="itemizedlist"><p class="title"><b>Encoder features</b></p><ul type="disc"><li><p>CAVLC/CABAC</p></li><li><p>Multi-references</p></li><li><p>
  Intra: all macroblock types (16x16, 8x8, and 4x4 with all predictions)
  </p></li><li><p>
  Inter P: all partitions (from 16x16 down to 4x4)
  </p></li><li><p>
  Inter B: partitions from 16x16 down to 8x8 (including SKIP/DIRECT)
  </p></li><li><p>
  Ratecontrol: constant quantizer, constant bitrate, single or multipass ABR,
  optional VBV
  </p></li><li><p>Scene cut detection</p></li><li><p>Adaptive B-frame placement</p></li><li><p>
  B-frames as references / arbitrary frame order
  </p></li><li><p>8x8 and 4x4 adaptive spatial transform</p></li><li><p>Lossless mode</p></li><li><p>Custom quantization matrices</p></li><li><p>Parallel encoding of multiple slices</p></li><li><p>Interlacing</p></li></ul></div></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="codec-h264-whatis"></a>7.1.3.2.聽What is H.264?</h4></div></div></div><p>
H.264 is one name for a new digital video codec jointly developed
by the ITU and MPEG.
It can also be correctly referred to by the cumbersome names of
"ISO/IEC 14496-10" or "MPEG-4 Part 10".
More frequently, it is referred to as "MPEG-4 AVC" or just "AVC".
</p><p>
Whatever you call it, H.264 may be worth trying because it can typically match
the quality of MPEG-4 ASP with 5%-30% less bitrate.
Actual results will depend on both the source material and the encoder.
The gains from using H.264 do not come for free: Decoding H.264
streams seems to have steep CPU and memory requirements.
For instance, on a 1733 MHz Athlon, a DVD-resolution 1500kbps H.264
video requires around 35% CPU to decode.
By comparison, decoding a DVD-resolution 1500kbps MPEG-4 ASP stream
requires around 10% CPU.
This means that decoding high-definition streams is almost out of
the question for most users.
It also means that even a decent DVD rip may sometimes stutter on
processors slower than 2.0 GHz or so.
</p><p>
At least with <code class="systemitem">x264</code>,
encoding requirements are not much worse than what you are used to
with MPEG-4 ASP.
For instance, on a 1733 MHz Athlon a typical DVD encode would run
at 5-15fps.
</p><p>
This document is not intended to explain the details of H.264,
but if you are interested in a brief overview, you may want to read
<a class="ulink" href="http://www.cdt.luth.se/~peppar/kurs/smd151/spie04-h264OverviewPaper.pdf" target="_top">The H.264/AVC Advanced Video Coding Standard: Overview and Introduction to the Fidelity Range Extensions</a>.
</p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="codec-x264-playback"></a>7.1.3.3.聽How can I play H.264 videos with
  <span class="application">MPlayer</span>?</h4></div></div></div><p>
<span class="application">MPlayer</span> uses
<code class="systemitem">libavcodec</code>'s H.264 decoder.
<code class="systemitem">libavcodec</code> has had at
least minimally usable H.264 decoding since around July 2004,
however major changes and improvements have been implemented since
that time, both in terms of more functionalities supported and in
terms of improved CPU usage.
Just to be certain, it is always a good idea to use a recent Subversion
checkout.
</p><p>
If you want a quick and easy way to know whether there have been
recent changes to <code class="systemitem">libavcodec</code>'s
H.264 decoding, you might keep an eye on 
<a class="ulink" href="http://svn.mplayerhq.hu/ffmpeg/trunk/libavcodec/h264.c?view=log" target="_top">FFmpeg Subversion repository's web interface</a>.
</p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="codec-x264-encode"></a>7.1.3.4.聽How can I encode videos using <span class="application">MEncoder</span>
  and <code class="systemitem">x264</code>?</h4></div></div></div><p>
If you have the subversion client installed, the latest x264
sources can be gotten with this command:
</p><pre class="screen">svn co svn://svn.videolan.org/x264/trunk x264</pre><p>
<span class="application">MPlayer</span> sources are updated whenever
an <code class="systemitem">x264</code> API change
occurs, so it is always suggested to use
<span class="application">MPlayer</span> from Subversion as well.
Perhaps this situation will change when and if an
<code class="systemitem">x264</code> "release" occurs.
Meanwhile, <code class="systemitem">x264</code> should
be considered very unstable, in the sense that its programming
interface is subject to change.
</p><p>
<code class="systemitem">x264</code> is built and
installed in the standard way:
</p><pre class="screen">./configure &amp;&amp; make &amp;&amp; sudo make install</pre><p>
This installs libx264.a in /usr/local/lib and x264.h is placed in
/usr/local/include.

With the <code class="systemitem">x264</code> library
and header placed in the standard locations, building
<span class="application">MPlayer</span> with
<code class="systemitem">x264</code> support is easy.
Just run the standard:
</p><pre class="screen">./configure &amp;&amp; make &amp;&amp; sudo make install</pre><p>
The <tt class="filename">./configure</tt> script will autodetect that you have
satisfied the requirements for <code class="systemitem">x264</code>.
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