[MPlayer-users] Re: Question on "trans-coding" with mencoder...

Jonathan Rogers jonner at teegra.net
Tue Aug 19 08:15:18 CEST 2003

Rainer Hantsch wrote:
> | I've had to run AVIs through mencoder twice when concatenating to get
> | everything straightened out. That is, cat the AVIs into mencoder with
> | -noidx, then run the result through mencoder again with -forceidx.
> | Mencoder can enode MPEG-1 video using libavcodec (I don't know about
> | MPEG-2), but it can only make AVIs.
> I concatenated both parts of a film with doing a
> cat 1.avi 2.avi | mencoder ...........
> as shown in the manual. The result is one big avi, which causes 10 times more
> activity on my dvd-rom as when I play 1.avi or 2.avi. I do not know what
> mencoder does, but it increases the system load extremely. And this shall
> become better with a second run? Why is this not mentioned in the manual?

If you're seeing a lot of drive activity, it's probably because the AVI 
has broken interleaving, which is mentioned. The manual isn't perfect 
and the maintainer will probably listen to well written suggestions.

Before asking the same question again, why don't you try my suggestion? 
Actually it is probably better to concatenate the MPEGs before encoding, 
as others have suggested.

> | Mencoder definitely does allow one to encode or copy an arbitrary
> | segment out of a source video. Check out the manual for the "-ss" and
> | "-endpos" options. The latter is unfortunately misnamed, since it
> | actually determines the total time of the output video, not the
> | timestamp to stop at.
> I never saw something about these option(s) in the German manual. As I said:
> The manual is definitely weak. Good meant, but incomplete and weak.

Did you read the manpage, or just the HTML docs? Those options are 
definitely in the English manpage, so if they're missing in the German 
one, that's a bug. Submit a bug report and it will probably be fixed.

> | There are several video editing tools, though I don't have much
> | experience with them. I have used GOPChop for cutting MPEG-2 Program
> | Streams.
> | <URL:http://fixounet.free.fr/avidemux/>
> | <URL:http://heroinewarrior.com/cinelerra.php3>
> | <URL:http://outflux.net/unix/software/GOPchop/>
> | <URL:http://kino.schirmacher.de/article/static/2>
> You are right, avidemux looks VERY interesting and should do what I wish. In
> theory -- practically, I tried to get avidemux working and found out that it
> does not compile on SuSE 8.0 because it needs so many different versions of
> libraries and (additional) tool(kits), that you have to change nearely the
> whole system! (Not that what I want to do on my stable running workstation.)
> Therefore I prefer binary rpm's for SuSE 8.0 (because I use SuSE 8.0), but
> they are relatively seldom.

You can always install libraries in alternate locations from the SuSE 
ones, like /usr/local, or somewhere in your $HOME. That can make 
configuring more tricky, but it allows one to have several versions 
installed simultaneously.

Jonathan Rogers

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