RepoMirrors
/
mpv
mirror of https://github.com/mpv-player/mpv
1
0
Fork 0
Code Issues Releases Wiki Activity

Remove 3-pass encoding guide (can break A/V sync), rescaling is not 

necessarily bad, typo.


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@12485 b3059339-0415-0410-9bf9-f77b7e298cf2
This commit is contained in:
diego 2004-05-17 23:35:36 +00:00
parent 8540ef2bb6
commit 193e10d0ab
1 changed files with 20 additions and 73 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

93
DOCS/xml/en/mencoder.xml
View File

@ -15,10 +15,8 @@ encoding with <application>MEncoder</application>.
</para>
<sect1 id="menc-feat-mpeg4">
<title>Encoding 2 or 3-pass MPEG4 (&quot;DivX&quot;)</title>
<title>Encoding 2-pass MPEG4 (&quot;DivX&quot;)</title>
<formalpara>
<title>2-pass encoding</title>
<para>
The name comes from the fact that this method encodes the file <emphasis>twice</emphasis>.
The first encoding (dubbed pass) creates some temporary files
@ -27,82 +25,32 @@ them yet (you can delete the AVI). In the second pass, the 2-pass output
file is created, using the bitrate data from the temporary files. The
resulting file will have much better image quality. If this is the first
time you heard about this, you should consult some guides available on the
Net.
net.
</para>
</formalpara>
<para>
This example shows how to encode a DVD to a 2-pass MPEG4 (&quot;DivX&quot;) AVI.
Just two commands are needed:
<screen>rm frameno.avi</screen>
remove this file, which can come from a previous 3-pass encoding (it interferes
with current one)
<screen>
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac copy -o <replaceable>movie.avi</replaceable>
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac copy -o <replaceable>movie.avi</replaceable>
</screen>
</para>
<formalpara>
<title>3-pass encoding</title>
<para>
This is an extension of 2-pass encoding, where the audio encoding takes
place in a separate pass. This method enables estimation of recommended
video bitrate in order to fit on a CD. Also, the audio is encoded only
once, unlike in 2-pass mode. The schematics:
</para>
</formalpara>
<procedure>
<step><para>
Remove conflicting temporary file:
<screen>rm frameno.avi</screen>
</para></step>
<step><para>
<emphasis>First pass:</emphasis>
<screen>mencoder <replaceable>file/DVD</replaceable> -ovc frameno -oac mp3lame -lameopts vbr=3 -o frameno.avi</screen>
An audio-only avi file will be created, containing
<emphasis role="bold">only</emphasis> the requested audio stream. Don't forget
<option>-lameopts</option>, if you need to set it. If you were encoding a
long movie, <application>MEncoder</application> prints the recommended
bitrate values for 650Mb, 700Mb, and 800Mb destination sizes, after this
pass finishes.
</para></step>
<step><para>
<emphasis>Second pass:</emphasis>
<screen>
mencoder <replaceable>file/DVD</replaceable> -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vpass=1:vbitrate=<replaceable>bitrate</replaceable><!--
--></screen>
This is the first pass of video encoding. Optionally specify the video
bitrate <application>MEncoder</application> printed at the end of the previous pass.
</para></step>
<step><para>
<emphasis>Third pass:</emphasis>
<screen>
mencoder <replaceable>file/DVD</replaceable> -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vpass=2:vbitrate=<replaceable>bitrate</replaceable>
</screen>
This is the second pass of video encoding. Specify the same bitrate
as in the previous pass unless you really know what you are doing.
In this pass, audio from <filename>frameno.avi</filename> will be
inserted into the destination file...and it's all ready!
</para></step>
</procedure>
<example>
<title>Example of 3-pass encoding</title>
<title>copy audio track</title>
<para>
<screen>rm frameno.avi</screen>
remove this file, which can come from a previous 3-pass encoding
(it interferes with current one)
2-pass encode of a DVD to an MPEG4 (&quot;DivX&quot;) AVI while copying
the audio track.
<screen>
mencoder dvd://2 -ovc frameno -o frameno.avi -oac mp3lame -lameopts vbr=3
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac copy -o <replaceable>movie.avi</replaceable>
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac copy -o <replaceable>movie.avi</replaceable>
</screen>
</para>
</example>
<example>
<title>encode audio track</title>
<para>
2-pass encode of a DVD to an MPEG4 (&quot;DivX&quot;) AVI while encoding
the audio track to MP3.
<screen>
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac mp3lame -lameopts vbr=3 -o <replaceable>movie.avi</replaceable>
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac mp3lame -lameopts vbr=3 -o <replaceable>movie.avi</replaceable>
</screen>
</para>
</example>
</sect1>
<sect1 id="menc-feat-mpeg">
@ -142,9 +90,8 @@ mencoder -of mpeg -ovc lavc -lavcopts vcodec=mpeg1video -oac copy <replaceable>o
<para>
Often the need to resize movie images' size emerges. Its reasons can be
many: decreasing file size, network bandwidth,etc. Most people even do
rescaling when converting DVDs or SVCDs to DivX AVI. This is <emphasis role="bold">bad</emphasis>.
Instead of even you doing so, read the <link linkend="aspect">Preserving aspect ratio</link>
section.
rescaling when converting DVDs or SVCDs to DivX AVI. If you wish to rescale,
read the <link linkend="aspect">Preserving aspect ratio</link> section.
</para>
<para>
@ -158,7 +105,7 @@ bilinear.
<para>
Usage:
<screen>
mencoder <replaceable>input.mpg</replaceable> -ovc lavc -lavcopts vcodec=mpeg4 -vf scale=640:480-o <replaceable>output.avi</replaceable>
mencoder <replaceable>input.mpg</replaceable> -ovc lavc -lavcopts vcodec=mpeg4 -vf scale=640:480 -o <replaceable>output.avi</replaceable>
</screen>
</para>
</sect1>