nero AAC codec not compatible with car deck

[TarkusShakti]

Re: nero AAC codec not compatible with car deck

The new version from 12 Feb still produces bad m4a files.

TS

[jtbse]

Re: nero AAC codec not compatible with car deck

I have no idea if this will be of any help or not, but there is one difference that I know of between files created by the Nero encoder and the iTunes encoder.

The files that Nero creates don't have their metadata optimized for "fast start streaming". Basically there is something called the mdat atom that Nero doesn't put in the correct place for fast-start streaming. I would think that this would only affect the ability to play the file via DAAP, but maybe the Kenwood expects the metadata in the .m4a to be optimized as well.

Basically two ways I know of to "optimize" the file created by Nero. 1) use mp4creator from the mpeg4ip utilities available on Rarewares. Or 2) use the "Optimize MP4" action available in MP3Tag.

Might be worth a try.

[TarkusShakti]

Re: nero AAC codec not compatible with car deck

Using UltraCompare to compare the files I found a lot of similarity and one small difference. The files that can play have a particular chunk of data in the front of the file and the files that don't play have that same chunk at the end of the file. Maybe the Kenwood expects that data to be in the front of the file? This is very nearly the only difference between the two.

Could this problem just be a difference in wrapping up the aac in a m4a container?

If the spec doesn't specify where that data goes; changing it in R12 to in-front would add compatibility with one more player. Since it seems both types work in computer-based environments.

TS

[TarkusShakti]

Re: nero AAC codec not compatible with car deck

I have no idea if this will be of any help or not, but there is one difference that I know of between files created by the Nero encoder and the iTunes encoder.

Thanks for joining the conversation.

But the problem isn't iTunes or nero. They both can create files that work. My problem is the R12 is doing something different with the nero output.

TS

[jtbse]

Re: nero AAC codec not compatible with car deck

Right...that sounds alot like the mdat atom that you're talking about. My understanding is that when the .m4a file is optimized for fast-start streaming, this atom is at the beginning of the file...a requirement for playing via Apple's DAAP protocol.

If you use the mp4dump utility from the mpeg4ip utilities I mentioned before, the metadata will be listed, and you'll probably see that the mdat entry shows up in different spots in the metadata for the two files.

Since I need to stream my .m4a's to Roku Soundbridges via DAAP or RCP, when using the Nero encoder in dmc 11.5, I always added an mp4optimize command as a Powerpack "After conversion run" step to avoid the problem.

Then I discovered I could also optimize the files using MP3Tag, which is a bit more "user friendly".

[Spoon]

Re: nero AAC codec not compatible with car deck

In a day or so we will release an aac >> mp4 codec which moves aac in and out of the mp4 container. This would possibly fix your issues (ie convert to aac, then >> to mp4 and there would be no extra atoms in the m4a file).

[TarkusShakti]

Re: nero AAC codec not compatible with car deck

jtbse -

That utility, mp4dump, really helps see the differences. Thanks for the reference.

And I believe I have solved the problem, because of it.

I saw the word hinttrack in the blob of data that was in the non-playing files. I turned this feature on in the sng front-end and made a file that except for date/time specific info, was identical to the non-playing file.

Is hinttrack required for basic conversion in R12? Can this option be switchable in the R12 interface?

TS

[LtData]

Re: nero AAC codec not compatible with car deck

A quick google search turns up that this is an option in the Nero AAC encoder:

-hinttrack: Generates an RTP hint track in output MP4 file.

There was also many results pointing to Apple or Quicktime Documentation.

Edit: Here's more on hint track: http://developer.apple.com/documenta...ection_36.html

[TarkusShakti]

Re: nero AAC codec not compatible with car deck

A quick google search turns up that this is an option in the Nero AAC encoder:There was also many results pointing to Apple or Quicktime Documentation.

Edit: Here's more on hint track: http://developer.apple.com/documenta...ection_36.html

Yes, I know it's an option for neroAacEnc, I used it when I created the "like file" above.

TS

[LtData]

Re: nero AAC codec not compatible with car deck

I think the option is in there as it solve more problems than it creates. However, this doesn't help you out. If there isn't an easy solution, you might have to use the CLI codec to encode to mp4 to leave out the -hinttrack option.

[TarkusShakti]

Re: nero AAC codec not compatible with car deck

I think the option is in there as it solve more problems than it creates. However, this doesn't help you out. If there isn't an easy solution, you might have to use the CLI codec to encode to mp4 to leave out the -hinttrack option.

Since it is an option and the R12 dMC provides switches for other options, maybe it could also be switchable in the interface (with the default being on, if you think more ppl need it than don't)

would that be reasonable?

TS

[LtData]

Re: nero AAC codec not compatible with car deck

That would be up to Spoon. However, it does sound reasonable if it is behind a "Advanced" button. Again, though, some users might uncheck this when they need it and vice-versa, so we will have to see what Spoon says.

[TarkusShakti]

Re: nero AAC codec not compatible with car deck

That would be up to Spoon. However, it does sound reasonable if it is behind a "Advanced" button. Again, though, some users might uncheck this when they need it and vice-versa, so we will have to see what Spoon says.

I would hope this could be done. I bought the "reference" edition and this was promoted as an expert's edition. Seems like that might be the place to put it. And it would please an existing customer!

TS

[LtData]

Re: nero AAC codec not compatible with car deck

I think there is a way to modify the options.txt file in the same folder as the neroEnc.exe to turn options on or off for your particular install. This might merit some looking into. Currently, I am on a computer without dMC so I cannot directly investigate this myself.

[TarkusShakti]

Re: nero AAC codec not compatible with car deck

It looks like there already is a switch for it in the R12 interface. But it looks turned off while it is really turned on...

Toggling the switch doesn't toggle the option.

TS