[MPlayer-DOCS] CVS: main/DOCS/xml/en encoding-guide.xml,1.36,1.37
Guillaume Poirier CVS
syncmail at mplayerhq.hu
Tue Dec 27 10:35:00 CET 2005
CVS change done by Guillaume Poirier CVS
Update of /cvsroot/mplayer/main/DOCS/xml/en
In directory mail:/var2/tmp/cvs-serv20612/DOCS/xml/en
New section: choosing the video codec for your encode: what to consider before picking it.
RCS file: /cvsroot/mplayer/main/DOCS/xml/en/encoding-guide.xml,v
retrieving revision 1.36
retrieving revision 1.37
diff -u -r1.36 -r1.37
--- encoding-guide.xml 6 Dec 2005 00:45:15 -0000 1.36
+++ encoding-guide.xml 27 Dec 2005 09:34:57 -0000 1.37
@@ -1350,6 +1350,111 @@
+<title>Choosing the video codec</title>
+ Choosing the video codec to use depends on several factors, some of
+ which widely depend on personal taste and technical constraints.
+ <emphasis role="bold">Compression efficiency</emphasis>:
+ It's quite easy to understand that newer-generation codecs are made
+ to yield better picture quality than previous generations.
+ Therefore, you cannot be wrong
+ <footnote id='fn-menc-feat-dvd-mpeg4-codec-cpu'>
+ <para>Be careful, however: decoding DVD-resolution MPEG-4 AVC videos
+ requires a fast machine (i.e. a Pentium 4 over 1.5Ghz or a Pentium M
+ over 1Ghz).
+ by choosing MPEG-4 AVC codecs like
+ <systemitem class="library">x264</systemitem> instead of MPEG-4 ASP codecs
+ such as <systemitem class="library">libavcodec</systemitem> MPEG-4 or
+ <systemitem class="library">XviD</systemitem>.
+ (To get a better grasp of what the fundamental differences between
+ MPEG-4 ASP and MPEG-4 AVC are, you would be well advised to read the entry
+ "<ulink url="http://guru.multimedia.cx/?p=10">15 reasons why MPEG4 sucks</ulink>"
+ from Michael Niedermayer's blog.)
+ Likewise, you should get better quality using MPEG-4 ASP instead
+ of MPEG-2 codecs.
+ However, newer codecs which are in heavy development can suffer from
+ bugs which have not yet been noticed and which can ruin an encode.
+ This is simply the tradeoff for using bleeding-edge technology.
+ What's more, beginning to use a new codec requires that you spend some
+ time becoming familiar with its available options, so that you know what
+ to adjust to achieve a desired picture quality.
+ <emphasis role="bold">Hardware compatibility</emphasis>:
+ It usually takes a long time for standalone video players to begin to
+ include support for the latest video codecs.
+ As a result, most only support MPEG-2 and MPEG-4 ASP
+ (beware: usually, not all MPEG-4 ASP features are supported).
+ Please refer to the technical specs of your player (if they are available),
+ or Google around for more information.
+ <emphasis role="bold">Best quality per encoding time</emphasis>:
+ Codecs that have been around for some time (such as
+ <systemitem class="library">libavcodec</systemitem> MPEG-4 and
+ <systemitem class="library">XviD</systemitem>) are usually heavily
+ optimized with all kinds of smart algorithms and SIMD assembly code.
+ That's why they tend to yield the best quality per fps.
+ However, they may have some very advanced options that, if enabled,
+ will make the encode really slow for marginal gains.
+ If you are after blazing speed you should stick around the default
+ settings of the video codec (which doesn't mean you should not experiment
+ with some of the options which are mentioned in other sections
+ of this guide).
+ You may also consider choosing a codec which can do multi-threaded
+ <systemitem class="library">libavcodec</systemitem> MPEG-4 does
+ allow that, resulting in small speed gains at the price of lower
+ picture quality.
+ <systemitem class="library">XviD</systemitem> has some experimental
+ patches available to boost encoding speed, by about 40-60% in typical
+ cases, with low picture degradation.
+ <systemitem class="library">x264</systemitem> also allows multi-threaded
+ encoding, which currently speeds-up encoding by 15-30% while lowering
+ PSNR by about 0.05dB.
+ <emphasis role="bold">Personal taste</emphasis>:
+ This is where it gets almost irrational: For the same reason that some
+ hung on to DivX 3 for years when newer codecs were already doing wonders,
+ some folks will prefer <systemitem class="library">XviD</systemitem>
+ or <systemitem class="library">libavcodec</systemitem> MPEG-4 over
+ <systemitem class="library">x264</systemitem>.
+ Make your own judgment, and don't always listen to what some people will
+ tell you to do or think: The best codec is the one you master the best,
+ and the one that looks best to your eyes on your display
+ <footnote id='fn-menc-feat-dvd-mpeg4-codec-playback'>
+ <para>The same encode may not look the same on someone else's monitor or
+ when played back by a different decoder, so future-proof your encodes by
+ playing them back on different setups.</para></footnote>!
+ Please refer to the section
+ <link linkend="menc-feat-selecting-codec">selecting codecs and container formats</link>
+ to get a list of supported codecs.
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