I was wondering.. How many file format does AAC has?
ADIF, ADTS, MP4 ? Can anyone explain the differences ?
Can aac exists alone with only ADIF / ADTS headers?
Is there any player capable of decoding ADIF / ADTS only streams?
What is the advantage of using MP4 streams when the 2 ADIF & ADTS is sufficient?

There's also LATM and no headers at all.

ADIF and ADTS may be sufficient for audio alone, but ADIF files are hard to seek and ADTS headers are a waste of bits (and ADTS files are also not as easy to seek as MP4).
MP4 files are smaller then the same AAC file with ADTS headers.

ADIF: for archiving
ADTS: for streaming

But LATM and MP4 can be streamed as well.
Another advantage of MP4 is that you can add MPEG-4 video.

Players capable of ADIF/ADTS AAC: Philips Expanium, Nokia phones (???).

Menno

I supposed that the file extension of ADTS / ADIF is NOT .mp4?
Is it .aac ?

there is no .adif or .adts extension

.aac files can be
- raw streams without header
- raw streams with adts header
- raw streams with adif header

when you mux the aac stream into .mp4 the headers get removed

Is there an application to mux aac stream to .mp4 files ?

mp4UI. 3ivx dshow mp4 muxer. foobar2k.

BTW, I noticed that under your nick it says "MPEG4 AAC developer". It seems weird that you ask about this stuff.

regards
echo

the 3ivx muxer might not mux it correctly (at least when muxing together with video) as there seems to be a problem in the available dshow aac parser filter (thats what the 3ivx guys say at least )
i already tried to contact the author of the aac parser but got not replay

I don't have the full ISO specifications with me!

OK then. Anyway you can find info about AAC in the audiocoding wiki.

regards
echo