[MPlayer-DOCS] CVS: main/DOCS/xml/en mencoder.xml,1.48,1.49

[Guillaume Poirier CVS]

CVS change done by Guillaume Poirier CVS

Update of /cvsroot/mplayer/main/DOCS/xml/en
In directory mail:/var2/tmp/cvs-serv28737/DOCS/xml/en

Modified Files:
	mencoder.xml 
Log Message:
Add missing <replaceable> tags.


Index: mencoder.xml
===================================================================
RCS file: /cvsroot/mplayer/main/DOCS/xml/en/mencoder.xml,v
retrieving revision 1.48
retrieving revision 1.49
diff -u -r1.48 -r1.49
--- mencoder.xml	11 Apr 2005 22:37:27 -0000	1.48
+++ mencoder.xml	12 Apr 2005 19:35:37 -0000	1.49
@@ -873,7 +873,8 @@
   stream <link linkend="menc-feat-mpeg4">during the encoding</link>.
   You can also extract the AC3 stream in order to mux it into containers such
   as NUT, Matroska or OGM.
-  <screen>mplayer source_file.vob -aid 129 -dumpaudio -dumpfile sound.ac3</screen>
+  <screen>mplayer <replaceable>source_file.vob</replaceable> -aid 129
+  -dumpaudio -dumpfile <replaceable>sound.ac3</replaceable></screen>
   will dump into the file sound.ac3 the audio track number 129 from the file
   source_file.vob (NB: DVD VOB files usually use a different audio numbering,
   which means that the VOB audio track 129 is the 2nd audio track of the file).
@@ -892,7 +893,9 @@
   First of all, you will have to convert the DVD sound into a WAV file that the
   audio codec can use as input.
   For example:
-  <screen>mplayer source_file.vob -ao pcm:file=destination_sound.wav -vc dummy -aid 1 -vo null</screen>
+  <screen>mplayer <replaceable>source_file.vob</replaceable>
+  -ao pcm:file=<replaceable>destination_sound.wav</replaceable>
+  -vc dummy -aid 1 -vo null</screen>
   will dump the second audio track from the file source_file.vob into the file
   destination_sound.wav.
   You may want to normalize the sound before encoding, as DVD audio tracks
@@ -903,10 +906,10 @@
   can do the same job.
   You will compress in either Vorbis or MP3.
   For example:
-  <screen>oggenc -q1 destination_sound.wav</screen>
-  will encode destination_sound.wav with the encoding quality 1, which is
-  roughly equivalent to 80Kb/s, and is the minimum quality at which you
-  should encode if you care about quality.
+  <screen>oggenc -q1 <replaceable>destination_sound.wav</replaceable></screen>
+  will encode <replaceable>destination_sound.wav</replaceable> with the
+  encoding quality 1, which is roughly equivalent to 80Kb/s, and is the
+  minimum quality at which you should encode if you care about quality.
   Please note that MEncoder currently cannot mux Vorbis audio tracks
   into the output file because it only supports AVI and MPEG
   containers as an output, each of which may lead to audio/video
@@ -1290,6 +1293,77 @@
 </para>
 </sect2>
 
+<sect2 id="menc-feat-dvd-mpeg4-muxing">
+<title>Muxing</title>
+
+<para>
+  Now that you have you encoded video, you will more than likely want
+  to mux it with one or more audio tracks into a movie container, such
+  as AVI, OGM, Matroska, or NUT.
+  <application>MEncoder</application> is currently only able to output
+  a video bitstream into MPEG (which is limited to MPEG-1 and -2 video
+  streams) and AVI containers.
+  Unfortunately, there are issues with the AVI container.
+</para>
+
+<para>Limitations of the AVI container</para>
+
+<para>
+  Although it's the most widely-supported container format after MPEG-1,
+  AVI also has some major drawbacks.
+  Perhaps the most obvious is the overhead.
+  For each chunk of the AVI file, 24 bytes are wasted on headers and
+  index.
+  This translates into a little over 5 MB per hour, or 1-2.5%
+  overhead for a 700 MB movie. This may not seem like much, but it could
+  mean the difference between being able to use 700 kbit/sec video or
+  714 kbit/sec, and every bit of quality counts.
+</para>
+
+<para>
+  In addition to gross inefficiency, AVI also has the following major
+  limitations:
+</para>
+
+<orderedlist>
+<listitem>
+<para>
+  Only fixed-fps content can be stored. This is particularly limiting
+  if the original material you want to encode is mixed content, for
+  example a mix of NTSC video and film material.
+  Actually there are hacks that can be used to store mixed-framerate
+  content in AVI, but they increase the (already huge) overhead
+  fivefold or more so they are not practical.
+</para>
+</listitem>
+
+<listitem>
+<para>
+  Audio in AVI files must be either constant-bitrate (CBR) or
+  constant-framesize (i.e. all frames decode to the same number of
+  samples).
+  Unfortunately, the most efficient codec, Vorbis, does not meet
+  either of these requirements.
+  Therefore, if you plan to store your movie in AVI, you'll have to
+  use a less efficient codec such
+  as MP3 or AC3.
+</para>
+</listitem>
+</orderedlist>
+
+<para>
+  With all of that said, <application>MEncoder</application> does not
+  support variable-fps output or Vorbis encoding.
+  Therefore, you may not see these as limitations if
+  <application>MEncoder</application> is the
+  only tool you will be using to produce your encodes.
+  However, it is possible to use <application>MEncoder</application>
+  only for the video encoding, and then use external tools to encode
+  the audio and mux it into another container format.
+</para>
+
+</sect2>
+
 </sect1>
 
 <sect1 id="menc-feat-telecine">