[MPlayer-DOCS] CVS: main/DOCS/xml/en mencoder.xml,1.74,1.75
Guillaume Poirier CVS
syncmail at mplayerhq.hu
Wed Jul 6 09:56:43 CEST 2005
CVS change done by Guillaume Poirier CVS
Update of /cvsroot/mplayer/main/DOCS/xml/en
In directory mail:/var2/tmp/cvs-serv31128/DOCS/xml/en
Modified Files:
mencoder.xml
Log Message:
Few fixes and suggestions by Jeff and Diego
Index: mencoder.xml
===================================================================
RCS file: /cvsroot/mplayer/main/DOCS/xml/en/mencoder.xml,v
retrieving revision 1.74
retrieving revision 1.75
diff -u -r1.74 -r1.75
--- mencoder.xml 5 Jul 2005 22:11:23 -0000 1.74
+++ mencoder.xml 6 Jul 2005 07:56:41 -0000 1.75
@@ -2726,25 +2726,27 @@
The quality of the encode yielded by this option highly depends
on personal preferences and on the type and monitor settings
used to watch it (typically, it will not look as good if it is
- bright or if it is a TFT monitor.
+ bright or if it is a TFT monitor).
</para></listitem>
<listitem><para>
<emphasis role="bold">qpel</emphasis>
- Increases the precision of the motion estimation from halfpel to
+ Raise the number of candidate motion vectors's by increasing
+ the precision of the motion estimation from halfpel to
quarterpel.
The idea is to find better motion vectors which will in return
reduce bitrate (hence increasing quality).
- However, quarterpel precision motion vectors are coded in the
- bitstream with a few bits, so if the content do not feature
- enough possibilities to find better motion vectors through
- <option>qpel</option>, it will in fact hurt compressibility.
+ However, motion vectors with quarterpel precision require a
+ few extra bits to code, but the candidate vectors do not always
+ give (much) better results.
+ Quite often, the codec still spends bits on the extra precision,
+ but little or no extra quality is gained in return.
Unfortunately, there is no way to foresee the possible gains of
<option>qpel</option>, so you need to actually encode with and
without it to know for sure.
</para><para>
<option>qpel</option> can be almost double encoding time, and
- requires as much as 30-60% more processing power to decode.
+ requires as much as 25% more processing power to decode.
It is not supported by all standalone players.
</para></listitem>
@@ -2752,12 +2754,12 @@
<emphasis role="bold">gmc</emphasis>
Tries to save bits on panning scenes by using a single motion
vector for the whole frame.
- This almost always raise PSNR, but significant slows down
- encoding (and also needs more processing power to decode).
+ This almost always raise PSNR, but significantly slows down
+ encoding (significantly slows down encoding).
Therefore, you should only use it when you have turned
<option>vhq</option> to the maximum.
- <systemitem class="library">XviD</systemitem>'s GMC (which are
- more sophisticated than DivX's are not supported by all
+ <systemitem class="library">XviD</systemitem>'s GMC is more
+ sophisticated than DivX's, but is only supported by few
standalone players.
</para></listitem>
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