The New Container MP4

[Cunhambebe]

Please take a look at this post first:
https://forum.videohelp.com/viewtopic.php?p=1456477#1456477
Now, some questions:

1.
When I produce (render) an Xvid file, (let's say with VirtualDub Mod, compressing with Xvid) the extension is already **.AVI.
-How can I render the same way to Xvid (using VD) with the new extension **.MP4? If it's impossible, I'll really have to use those applications mentioned on the topic above?

OR

2.
Will I have to use VD first to create the Xvid file and AVI container and only then those already mentioned applications to create the MP4 container? is that the correct way or I'll have to use those applications compressing directly to Xvid with the extension MP4?

3.
-Can I use my own Xvid videos already muxed with AC-3 files in an AVI container to create an MP4?;
-Can I mux an Xvid (already in an MP4) with AC-3 files?

Thanks so much in advance :@)

[celtic_druid]

I wouldn't call mp4 new. The specs have been finalised for ages now.

VirtualDubMod can't output mp4 and VfW isn't really designed for it. If you weren't encoding with bframes I guess it would be possible. Like in the old DivX4 codec. Not that its output was spec compliant I don't think.

Just take your avi and use mp4box/yamb to remux.

mp4 specs don't allow for AC3. It would be possible as a private stream (as everything is) however there is no tools to do it and it is a bad idea anytway. If you want multichannel audio, you need to convert to aac.

[Cunhambebe]

Thanks for the input, so I guess I'd better keep my old and good AVIs for my Xvids.
Sorry for my ignorance, but what's aac?

If you want multichannel audio, you need to convert to aac.

[guns1inger]

aac

[Cunhambebe]

Thanks - BTW, which one do you prefer? AVI or MP4?

[celtic_druid]

Tricky question. I have a hardware player that supports avi only. mp4 is definatly the better container though. It is also the official MPEG-4 container.

[Cunhambebe]

Thanks again for the input. Anyway, since I prefer to mux my own Xvid video with AC-3 files, I guess I'd better keep rendering to Xvid with VirtualDub (and the AVI container). About your remark on the MP4 container: I was reading a post on an Brazilian Video Community at Orkut; the person said exactly this, that MP4 is better than AVI.
Cheers!