VBR MP3 and AVIMux

[valnar]

I've searched all through these forums and didn't quite find the answer I was looking for.

Coming into the DivX game a little late, I have not had the opportunity to follow all the developments.

I have been making DivX files with CBR MP3 audio out of laziness and desire for perfect compatibility. I now want to try a VBR/ABR MP3 file and mux it with AVIMux, which I believe to be the best AVI muxing application.

Are we at a point where a "wav" header is no longer required on the MP3 file before muxing? Does it still need it? And if so, which applications do this the best?

Thanks,
Robert

[alexnoe]

A WAV header is not required for CBR or VBR ("ABR" is VBR).

If you feed AVI-Mux GUI with a WAV-file with MP3-VBR contents, it will make crap actually...

[iago]

alexnoe,

First, many thanks again for this great tool. I have one question: when muxing VBR MP3, should "MP3 CBR frame mode" (which comes ticked by default) in the output options be unchecked or kept as it is?

So far, I haven't encountered any synch problems by leaving it checked when muxing VBR MP3 and the muxing overhead decreases by ~3mb compared with Nandub/VirtualDubMod muxing.

Anyway I just wanted to make sure by asking you, the author of this powerful tool ;).

Sorry if I'm missing something that was already answered before.

best regards,
iago

[alexnoe]

It is called "MP3 CBR frame mode" because it influences the way MP3 CBR is handled...this option is not even looked at when muxing MP3-VBR :D

With 1.14, there is even a chance that WAVs containing AC3, DTS or MP3-VBR work.

[iago]

Oh, thanks for the quick reply. Glad to hear that, it's a relief! ;)

[iago]

Dear Alexnoe,

I thought this might be the suitable place to discuss the issue since I didn't know exactly on which board to post this problem:

I muxed a DivX 5.0.5 video with 128kbps abr-mp3 (created with BeSweet v1.5b25) into avi container using AVI-Mux GUI 1.15.6. When I try to play the resulting avi file with Media Player Classic 6.4.7.5, I get the following message:

"This AVI file was not prepared for sequential reading, the alternative 'Avi Splitter' will now let the default one handle it. The complete reinterleaving of this file is strongly recommended before burning it onto a slow media like cd-rom."

Any ideas why?

regards,
iago


edit-> one more question just out of curiosity: Is it safe to mux cbr-mp3 into avi using AVI-Mux GUI (1.15.6)? When I check a cbr-mp3 audio file before muxing, the verification result always displays it as "vbr-mp3"...?

[alexnoe]

There is a problem with some later versions of lame encoder, so that CBR files are not detected properly by avi-mux gui. I'll have to look into this.

This MPC message means that a certain header flag is not set. Actually, this should not really matter...and I *thought* I had set that flag, beginning with 1.15.6 ...

[iago]

alexnoe,

Thanks for the explanations. Now, things have become clearer for me.

Regarding the cbr-mp3 issue:

There is a problem with some later versions of lame encoder, so that CBR files are not detected properly by avi-mux gui. (alexnoe)Now, that's really interesting since I believe the "lame_enc.dll" that comes with BeSweet v1.5b25 is from "lame-3.90.3" package, the lame version which is still the recommended one (by Hydrogenaudio) and considered most reliable afaik...

Anyway, once again thanks for your great tool!..

best regards,
iago

[alexnoe]

Maybe the problem only affects AVI-Mux GUI :p
i'll have to look at this when i have time (meaning when there are no exams...)