Change container mp4 -> m4a

[Yayita]

What is the easiest way to change an audio mp4 to m4a without tampering with the aac audio track??

I have a player that only recognizes m4a, and most of my files are mp4...

[KpeX]

rename file.mp4 file.m4a
Mp4 and M4A are the same container, M4A is just generally used to indicate an audio only file. But the container format is identical.

[tedgo]

If you want to change the extension of all tracks in one folder at once, try the little program "sweep" (the "Sweep.zip")
http://www.saunalahti.fi/~cse/files/
Just copy the sweep.exe to your WINDOWS/system32-folder, open a Command Window in the folder with the *.mp4s and type:
sweep.exe ren *.mp4 *.m4a

Btw. the easiest way to open a command window in a specific folder is the "Cmdhere.exe" (Open Command Window Here)-Powertoy from Microsoft (only for XP)
http://www.microsoft.com/windowsxp/downloads/powertoys/xppowertoys.mspx

[celtic_druid]

If all the files are in one folder, then why bother with sweep?
ren *.mp4 *.m4a will do the job.

[tedgo]

Sorry, i forgot that its possible without sweep.
I usually used sweep to rename the files in different folders (by creating a *.reg-file) as posted here:
http://www.hydrogenaudio.org/forums/index.php?showtopic=21351&view=findpost&p=208778
But this will rename video.mp4s too...

[Yayita]

Thanks guys for the help.

Encoding with Nero went nice'n'easy. Renaming was not a problem thanks for the suggestions.

However my player a '05 Kenwood car player (most '05 models play supposedly AAC) will not play my m4a files.

The manual is a joke and the customer service has no idea of what's going on.

They suggested that I use their own media manager which creates an m4a file. I used it to test and it creates a file that mp4UI can not read it crashes. While, it does not crash with the nero mp4 / m4a files.

So obviously there is a difference with what kenwood calls an m4a and the rest of the world calls m4a.

My intuition is that kenwood media manager creates an aac file without container and uses the extension m4a.
How can I prove this?

I also used mkvtoolnix and it recognizes (the kenwood file) as mp4a.
I merged it into an mkv and MPC says its aac audio track when it plays it.

I would like to know what type of file this is so I can replicate it with the much more user controllable nero aac encoder.

help appreciated, and i'll keep you posted if I solve this...

[bond]

can you upload such a kenwood file plz :)

[SeeMoreDigital]

Originally posted by bond
can you upload such a kenwood file plz :) Yes please to this too!

[Yayita]

Thanks guys for your interest.

Heres is a 77kb, 5 second kenwood m4a sample. It will appear once a board moderator approves it.

Please let me know what this is.

[bond]

the files is a little bit strange, if the stream where a video stream it would be variable framerate and include b-frames (as signalled in the stts and ctts atoms) :D

but its definitely aac-in-mp4, no idea what the difference to "normal" mp4 files is :confused:

[SeeMoreDigital]

Firstly the file crashed mp4UI...

But after playing the file in Foobar2000 and looking at its properties, I noticed that no information had been allocated against "DATE" Metadata: -

http://img233.echo.cx/img233/8287/snap17wa.gif

However, as soon as the "DATE" Metadata line is deleted or if a year date is added, the file appears to work fine.


Cheers

[eb]

Sample can played in VLC or MPlayer.
Below information from MPlayer can be useful

http://img177.echo.cx/img177/9759/m4asample3da.jpg (http://www.imageshack.us)

eb

[eb]

To convert to .mp3 use GraphEdit as below"

http://img177.echo.cx/img177/1826/m4asample18bm.jpg (http://www.imageshack.us)

sample converted to .mp3

ftp://www.eb.enterpol.pl:eb@www.eb.enterpol.pl/mp4_2_mp3.mp3

sample converted to .aac

ftp://www.eb.enterpol.pl:eb@www.eb.enterpol.pl/mp4a_2_aac.aac

eb

EDIT sample .mp3 with 48kHz

ftp://www.eb.enterpol.pl:eb@www.eb.enterpol.pl/mp4a_2_mp3_48kHz.mp3

[Yayita]

So besides the missing date value in the metadata there is no difference between the attached m4a and a normal nero mp4 ?

Why is my player playing the first and not nero files?

I really would like to know, I would really like to use nero encoder and trash kenwood's "phat media manager".

Help Please.

:rolleyes:

[SeeMoreDigital]

Have you considered using Apple's iTunes?

It provides a free AAC (as well as MP3 and WAV) encoder!


Cheers

[Yayita]

I finally figured it out.

Look at this mp4ui screen from a nero file:

The tracks 2 and 3 in the "Other" section are not there in the kenwood's mp4s. So if I delete these two tracks with mp4ui they are played by my player.

Tarack 2 is OD and track 3 is BIFS, I do not know what these are.

So I know now how to play the files. Now if I knew how to tell nero not to include these tracks, or to batch delete these extra tracks my life would be saved...

:sly:

[bond]

omg, how crappy, a player that crashes because of the bifs/od streams :D

tell kenwood to fix that

[Yayita]

I forgot to mention it in my previous post, I am absolutely letting kenwood know my opinion, hopefullly there will be firmware updates.

What are those BIFS/ OD streams?

[SeeMoreDigital]

Originally posted by bond
omg, how crappy, a player that crashes because of the bifs/od streams :D Agreed....

That said, iTunes does not generate AAC streams with BIFF and OD data either: -

http://img124.echo.cx/img124/9265/itunesmetadata0uq.gif

I wonder whether the iPod will crash when presented with AAC streams containing BIFF's and OD's?


Cheers