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Topic: Nero AAC Encodes - MPEG-2 or MPEG-4? (Read 13878 times) previous topic - next topic
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Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #25 –
maybe no one noticed my last post before...
WARNING:  Changing of advanced parameters might degrade sound quality.  Modify them only if you are expirienced in audio compression!

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #26 –
Do you notice any difference between these files?

I wonder what are those mismatches, but, if they don't f*ck up your file, I think you don't need to worry.

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #27 –
Quote
Do you notice any difference between these files?

I wonder what are those mismatches, but, if they don't f*ck up your file, I think you don't need to worry.

Yeah, I'm sure it would play fine in an Expanium lol, but that isn't what I am going for.  I guess I am one of those guys who is anal about offsets and file differences, regardless of what little perceptible difference there is.  I'd like to know whether this sound stream IS what is being affected, and if not, thats great, but then what is?  The files are the same size, but one has 31 bit differences.  One is "Nero ISO standard" and one is converted through a hack.  I'd like to see this process improved until we know what these differences are, and until we can do a perfect conversion.  I don't know enough about the container or the audio encoding formats to tell what the differences between these two files are, I can just tell you what I did to get both of them.
WARNING:  Changing of advanced parameters might degrade sound quality.  Modify them only if you are expirienced in audio compression!

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #28 –
Seems all the confusion here is direct result of a short-sighted Mpeg4 standards commitee changing a long existing standard, breaking backwards compatability with existing hardware/software.  Software (QT6, Envivio, DSS, MPEG4ip, etc) must be updated to reflect this corrigendum and ensure interoperability.  Seems we will have to wait for MPEG4 Standard to regain acceptance and propagate to software.

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #29 –
There is no need to change QT6, Envivio, etc.. as none of that software supports ADTS AAC files - the only part of the MPEG-4 standard that was changed was the ADTS header,  which is not good IMO (I would oppose this and offer reasons to back that up, but in that time we weren't MPEG members)  but it certainly doesn't ruin any compatibility if the MPEG-4 file format is used - which I strongly recommend.

Please send those two files to (idimkovic _AT_ nero dot com) and I'll try to investigate what is causing differences - maybe ADTS headers are just different and there is no spectral difference (try opening these two files in CoolEdit and do copy/mixed paste with the second file on first  to get difference signal)

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #30 –
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But mp4ui has no batch processing, AFAIK.

Yes, it has, but only for AAC->MP4, not the other way round. The developer wrote in a mail that he might modify his app when he's back from Hawaii at the end of March.

Quote
So modified mp4creator would have possibility to change object id (or ignore it and select output type, say, depending on some switch)? Did I get it right?


No, the modification that Ivan suggested is a "hardcoded" hack that would always put out MPEG-2 AAC files, as far as I've understood it.
ZZee ya, Hans-Jürgen
BLUEZZ BASTARDZZ - "That lil' ol' ZZ Top cover band from Hamburg..."
INDIGO ROCKS - "Down home rockin' blues. Tasty as strudel."

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #31 –
Quote
Next, I used Ivan & Menno to convert the file.
[...]
Edit:  btw, file 1 is the original mp4 mpeg-4 AAC LC file (created by Nero) converted to mpeg-2 AAC LC with mp4UI and Ivan & Menno.  File 2 is the original mpeg-2 AAC LC from Nero.

There's something wrong here: when you write "Ivan & Menno", you mean mp4creator, right? So maybe you should use mp4UI for the reconversion, too (not only for changing the ObjectType ID), and not mp4creator, because these two might behave differently.

Another possibility: did you tag this MP4 file with foobar2000 maybe, before you changed it with mp4UI and mp4creator?
ZZee ya, Hans-Jürgen
BLUEZZ BASTARDZZ - "That lil' ol' ZZ Top cover band from Hamburg..."
INDIGO ROCKS - "Down home rockin' blues. Tasty as strudel."

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #32 –
Quote
So maybe you should use mp4UI for the reconversion, too (not only for changing the ObjectType ID), and not mp4creator, because these two might behave differently.

Unfortunately, mp4ui can only extract 'raw mpeg-4 audio file (.bin)', which has no header at all, I assume.

Quote
I wonder what are those mismatches, but, if they don't f*ck up your file, I think you don't need to worry.

Yeah (jus' kiddin'  )

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #33 –
Quote
Unfortunately, mp4ui can only extract 'raw mpeg-4 audio file (.bin)', which has no header at all, I assume.

Right.

If you want to extract ADTS AAC files, you need MP4creator.

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #34 –
Quote
Quote
Unfortunately, mp4ui can only extract 'raw mpeg-4 audio file (.bin)', which has no header at all, I assume.

Right.

If you want to extract ADTS AAC files, you need MP4creator.

Hmm, Markus Brenner (the developer) wrote in his mail that mp4UI would be able to do everything that mp4creator can do. So inserting ADTS headers in each frame when reconverting to MPEG-2 AAC seems to be another new item on his todo list... 
ZZee ya, Hans-Jürgen
BLUEZZ BASTARDZZ - "That lil' ol' ZZ Top cover band from Hamburg..."
INDIGO ROCKS - "Down home rockin' blues. Tasty as strudel."

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #35 –
I successfully modified mp4creator to output aac files copatible with philips expanium players, even when they contain mpeg-4 objects like (QuickTime6 ones). If you wish, I can send you a copy of my modified mp4creator.
Regards

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #36 –
I just bought a Philips Expanium EXP401 and the audio level playing AAC is about half the volume as MP3s. I've encoded the AAC directly from WAV (ripped from CD) with both Nero AAC plugin and PsyTel encoder. I suspect my unit is bad, so what I would like to know is if anyone here has this unit and has encoded with Nero, if you've experiened the same. Or is the audio level in the EXP401 identical when playing AAC and MP3 ( It should be the same, right? ) And I mean low, because with the volume level all the way to the max, it's about 3 to 4 DB lower than when playing an MP3. I've tested encoding different WAV files, and the same thing happens. If I play the AAC in WinAmp, it sounds exactly the same (audio level ) as the MP3!, so I know the AAC file is correct.


Appreciate any response, because I just bought this player yesterday, so I have time to go and change it for another unit  B)

Thanks,
-kwag

www.kvcd.net

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #37 –
I had the same problems with test expaniums, so I guess it is related to all of them.
 

Nero AAC Encodes - MPEG-2 or MPEG-4?

Reply #38 –
Quote
I had the same problems with test expaniums, so I guess it is related to all of them.

Thanks Ivan.
So I guess it means a trip back to the store to return the item 
Pity, it's such a nice little unit!

-kwag