[MEncoder-users] How to repackage MP4 files to avi container?

Grozdan neutrino8 at gmail.com
Sat May 15 14:53:29 CEST 2010

On Sat, May 15, 2010 at 7:23 AM, Miroslav Rovis <m.rovis at inet.hr> wrote:
> Hash: SHA1
>> Yes, intermediate, which means you mux it to another container right
>> away and don't let it rot somewhere in a folder for many months, or
>> even years.
> ...
>> mplayer doesn't only deal well with avi files, it deals well with mp4,
>> mkv, ts, ogm, you name it.
> ...
>> > Sure. You're right. The problem, Grozdan, that I often have with mp4,
>> > is bad sync, and when I store h264/aac into avi files, the sync is
>> > just right, or not too bad...
>> That's not related to the mp4 container itself, but to crappy muxing
>> and/or encoding. Remuxing it to avi won't magically fix the sync,
>> unless you manually adjust it
> Of course not. I didn't mean that it would.
> The "intermediate" avi had the sync right in most of the cases...
>> > So that is what made me think about using avi. For another thing,
> here:
>> >> Avi is a very basic container and it doesn't even support some
>> >> important parts of modern video codecs. This combined with some ugly
>> >> hacks added to support modern stuff, makes it even more shitty.
> Not to
>> >> mention its overhead compared to more modern containers like mkv
> & mp4
>> > I know now more or less that it is so. The problem is, I am not at all
>> > yet familiar with so many other issues in the encoding business, and I
>> > haven't learned how to use Matroska properly....
>> It's no different than mp4. If you want to remux your mp4s to mkvs,
> just do
>> mkvmerge file.mp4 -o output.mkv
> With the bad sync... Oh, well, I can cut-n-paste patch the streams and
> mux them synced with MP4Box...

As I said, both mkvmerge and mp4box have options to adjust delay of
audio during muxing and if you do it right, you can get rid of the

>> Again, if the original has sync issues, remuxing to another container
>> won't magically fix it unless you manually adjust the sync, which
>> mkvmerge and mp4box allow to do that
> Ah, there's another way to do it! I'll be taking a look at the docs
> and manuals (sigh).
>> > 1) Can MPlayer manipulate/reencode/whater mkv files as potently as it
>> > does with avi files?
>> No, mplayer is a video player. It has no encoding capabilities. Use
>> mencoder or ffmpeg for that
> I didn't think it did. It's the same program I think... mplayer and
> mencoder also have same man page. Likewise, I meant mencoder in fact.

Not the same program. Mencoder is mplayer's encoder and while it uses
mplayer's codebase (libavcodec, demuxers, muxers, filters, etc) it
can't visually render video so you can't use it to watch video but you
can to encode it. They have the same man page because they both share
the same demuxers, muxers, filters, etc. Whatever mplayer can play,
mencoder can encode it

>> > and
>> > 2) Can it do as well with MP4 files? And can the sync problems grow
>> > with these (upon further manipulating), more than with the avi files?
>> > I think you are right... But that's a handful right now, for me, to
>> > plain learn this Matroska business...
>> Yes and yes. Sync can grow is the file is somehow badly encoded and
>> mencoder isn't able to compensate. It depends on the file and its
>> issue
>> > So:
>> > 3) If I keep just the intermediate avi container format, can AAC and
>> > H264 still be put just back into avi file, as they were produced in an
>> > avi file container when mplayer encoded them, like I tried to put them
>> > "back in" in my previous post, or is it really a crap idea and nothing
>> > else...
>> Yes it can, but I wouldn't recommend it. Still, if you want to do
>> that, try avidemux
> I'll just probably move completely to mkv's...
> Thanks. This was useful for me.
> Miro
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