[MPlayer-DOCS] CVS: main/DOCS/xml/en encoding-guide.xml,1.45,1.46
Guillaume Poirier CVS
syncmail at mplayerhq.hu
Mon Mar 6 08:19:03 CET 2006
CVS change done by Guillaume Poirier CVS
Update of /cvsroot/mplayer/main/DOCS/xml/en
In directory mail:/var2/tmp/cvs-serv17223/DOCS/xml/en
Modified Files:
encoding-guide.xml
Log Message:
various improvements of the section "Choosing the video codec"
Index: encoding-guide.xml
===================================================================
RCS file: /cvsroot/mplayer/main/DOCS/xml/en/encoding-guide.xml,v
retrieving revision 1.45
retrieving revision 1.46
diff -u -r1.45 -r1.46
--- encoding-guide.xml 5 Mar 2006 22:50:56 -0000 1.45
+++ encoding-guide.xml 6 Mar 2006 07:19:00 -0000 1.46
@@ -1356,15 +1356,17 @@
<title>Choosing the video codec</title>
<para>
- Choosing the video codec to use depends on several factors, some of
+ Which video codec is best to choose depends on several factors,
+ like size, quality, streamability, usability and popularity, some of
which widely depend on personal taste and technical constraints.
</para>
<itemizedlist>
<listitem><para>
<emphasis role="bold">Compression efficiency</emphasis>:
- It is quite easy to understand that newer-generation codecs are made
- to yield better picture quality than previous generations.
- Therefore, you cannot go wrong
+ It is quite easy to understand that most newer-generation codecs are
+ made to increase quality and compression.
+ Therefore, the authors of this guide and many other people suggest that
+ you cannot go 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
@@ -1374,12 +1376,11 @@
<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.
+ (Advanced codec developers may be interested in reading Michael
+ Niedermayer's opinion on
+ "<ulink url="http://guru.multimedia.cx/?p=10">why MPEG4-ASP sucks</ulink>".)
+ Likewise, you should get better quality using MPEG-4 ASP than you
+ would with MPEG-2 codecs.
</para>
<para>
However, newer codecs which are in heavy development can suffer from
@@ -1417,22 +1418,23 @@
</para>
<para>
If you are after blazing speed you should stick around the default
- settings of the video codec (which does not mean you should not experiment
- with some of the options which are mentioned in other sections
- of this guide).
+ settings of the video codec (although you should still try the other
+ options which are mentioned in other sections of this guide).
</para>
<para>
You may also consider choosing a codec which can do multi-threaded
- processing.
+ processing, though this is only useful for users of machines with
+ several CPUs.
<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.
+ allow that, but speed gains are limited, and there is a slight
+ negative effect on picture quality.
+ <systemitem class="library">XviD</systemitem>'s multi-threaded encoding,
+ activated by the <options>threads</option> option, can be used to
+ boost encoding speed — by about 40-60% in typical cases —
+ with little if any 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.
+ encoding, which currently speeds up encoding by 15-30% (depending on
+ the encoding settings) while lowering PSNR by about 0.05dB.
</para></listitem>
<listitem><para>
@@ -1444,9 +1446,12 @@
<systemitem class="library">x264</systemitem>.
</para>
<para>
- Make your own judgment, and do not 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
+ You should make your own judgement; do not take advice from people who
+ swear by one codec.
+ Take a few sample clips from raw sources and compare different
+ encoding options and codecs to find one that suits you best.
+ The best codec is the one you master, 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
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