[Matroska-users] RE: [Matroska-general] how can I covert mkv files into to avi?

Rolf Ernst rolf.ernst at 24hourloop.com
Mon Jan 21 20:46:02 CET 2008

Pretty much agree with everything that was said here. I am not sure whether you are working under Windows/Mac/Linux but I assume you are using Windows. 

Install the mkvmerge-gui. Run it and drop your mkv file onto it. It will tell you what sort of streams you have in there. (mkvinfo tells you, too, but probably way too much information than you need). 

If it is stuff that can be muxed into an avi container you simply use mkvextract (or the gui), split it into it's elementary streams and use something like avisynth or virtualdub to mux it back together. If you want, you can re-encode the audio to mp3 in the process. 

Your first step should be to find out what you have. 

I very much recommend against a two-step recompression process. If at all possible you should leave it at that ratio but if you have to, choose soome high qualityt codec and only do it obnce (h.264 or VC1 comes to mind). VC1 can be muxed into a wmv file with wma audio and played on most windows computers. H.264 with AAC can be played on pretty much every operating system, but you might have to download the free directshow filter for windows. 

But then again, why not stay with mkv altogether as it gives you the least muxing overhead? 


----- Original Message ----- 
From: "Ivan Kowalenko" <ivan.kowalenko at gmail.com> 
To: "help Questions, instructions, talk about Matroska" <matroska-users at lists.matroska.org>, "Fermin Quant" <ferminquant at hotmail.com> 
Sent: Monday, January 21, 2008 1:11:37 PM (GMT-0600) America/Chicago 
Subject: Re: [Matroska-users] RE: [Matroska-general] how can I covert mkv files into to avi? 

On Jan 21, 2008, at 12.54, Fermin Quant wrote: 

> Actually, the reason I want to turn them into avi was because I want 
> to make them smaller, and I don't know how to manipulate the mkv 
> files. 

The best program for that is, in my opinion, ffmpeg. It'll do 
everything you could ever want, with a high degree of precision and 
efficiency. Plus it has native support for almost everything on the 
planet (except that super-proprietary Windows Media stuff, but that 
can be hacked in, kinda) 

> Becuase I have 24 minutes episodes of 250-300 MB, and I want to turn 
> them to about 90 MB, by turning them into 170MB avi then into 90MB 
> RMVB, that was my original plan. 

OK, this is a very very bad idea. First, likely if it's 24 minutes at 
300 MB, it's probably high definition, maybe 720p. I don't *know* but 
I'm guessing. So you'll lose a lot of graphical detail just by 
downscaling. Second, you're talking about going from lossy (MKV 
unknown codec @ 300MB) to lossy (AVI unknown codec @ 170MB) to lossy 
(RMVB @ 90MB). You're going to lose ten tons of quality in your first 
step. Plus RMVB is, relatively speaking, a rather low quality codec, 
compared to something like H.264/x264/AVC (same thing, three different 
names), which is what your source video probably is already. If you 
REALLY REALLY need it, try and reduce that all to one step (MKV -> 
RMVB), or at least use a lossless codec for your middle step (maybe 
DV, but that's got some rather picky requirements, and it's usually 
highly impractical). 

> But since its not possible because of the VFR, could you tell me how 
> to make the mkv files smaller? 

It's rare to find variable framerate material. Most of the time, 
people just use MKV because it's friendly with H.264 and AC3/Dolby 
Digital/A52 (again, same codec, three different names) in the same 
file. Those two codecs happen to be the codecs of choice when it comes 
to distributing high definition content on the tubes these days. My 
advice, if you absolutely need to do this (remember, you might lose 
additional data, like subtitles, additional audio tracks, chapter 
points, etc.) is to look into ffmpeg (open source, cross platform, has 
tons of GUIs for Windows, Linux and Mac OS X) and MEncoder (sister 
project of MPlayer, open source, cross platform, not as many nice GUIs 
and ffmpeg, but it does some nicer stuff, http://mplayerhq.hu). If you 
can't keep the content in the MKV file (some set-top box won't play 
it, your computer can't decode high def content in real time, etc) 
then at least cut out the RMVB stuff, since that's got less support 
than MKV and the quality will be (after your three step process) about 
ten times worse than your source. Both ffmpeg and MPlayer/MEncoder 
have incredibly responsive and helpful mailing lists if you need help, 
and there's tons of tutorials for both on the web. 

> > Date: Mon, 21 Jan 2008 14:33:04 +0100 
> > From: chris at matroska.org 
> > To: matroska-users at lists.matroska.org; ferminquant at hotmail.com 
> > Subject: Re: [Matroska-general] how can I covert mkv files into to 
> avi? 
> > 
> > Fermin Quant schrieb: 
> > > I've been trying with an mkv file I found on the internet to 
> extract 
> > > the video and audio separately and rejoining them into avi, but 
> with 
> > > no succes. 
> > > I tried with most of the tools you have on your site, but none of 
> > > those are able to get the video out properly or even convert the 
> audio 
> > > to mp3. 
> > > From your experiences, which is the best way to convert mkv 
> files into 
> > > avi files? 
> > 
> > This email belongs into matroska-users, not matroska-general. 
> Please try 
> > to respect that for future communication. 
> > 
> > Trying to convert MKV files into AVI files is big nonsense, to start 
> > with. MKV was created to overcome the limitations of the old, 
> redundant 
> > AVI container. AVI was created about 20 years ago by Microsoft, 
> and then 
> > abandoned for their own, better (but closed) WMV/ASF format/ 
> container. 
> > All the extensions to AVI which were added lateron were never really 
> > successful, mainly because most existing tools/apps for AVI 
> handling, 
> > with Virtualdub being the most important, couldnt make use of 
> them. AVI 
> > by itself is not even VBR MP3 capable, at least not in a clear 
> manner. 
> > 
> > I recommend to convert your MKV files into DVDs if you would like 
> to see 
> > them in your saloon/living room on your DVD player, thats the 
> safest way 
> > and will preserve most of the quality of the MKV file (of course, 
> > depending on what video/audio codecs were used in your MKV). Some 
> video 
> > streams in MKVs, especially anime material, are VFR (Variable 
> Framerate) 
> > and these video streams can no way be put into AVI, no matter what 
> video 
> > codec you are using to recompress it, as AVI is bound to have a 
> dixed 
> > time delay from one frame to the next (CFR = Constant Framerate). 
> > DVDs/MPEG on the other hand is VFR capable (in principle, not sure 
> if 
> > thats true for every DVD player out there), as its younger and more 
> > modern than AVI. 
> > 
> > The best tools to convert MKVs into DVDs are probably S.U.P.E.R. and 
> > Convert-X-to-DVD. For the latter there is a link on our homepage, 
> > technical/guide section, bringing you to a guide on how to use this 
> > tool. Using DVDSanta - as described on our homepage - is not 
> recommended 
> > anylonger, as its developers are too stupid or not interested to fix 
> > even some of the more important bugs this program has, especially 
> when 
> > trying to open MKV files. 
> > 
> > Best Regards 
> > 
> > Christian 
> > matroska project admin 
> > 
> > 
> > 
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