I encoded some stuffs with FAAC 1.24 main profile but iTunes can't play them. I think iTunes will support it someday, right?

Currently, it only supports LC profile

I personally think that is doubtful. Neither QT or iTunes offer Main or LTP profiles for encoding, and you have to wonder why they would: the increase in efficiency is quite small for all the extra resources used. Thus, they probably won't support it for decoding, either. Apple needs to get the decoder and encoder problems fixed with QT 6.5.1 LC-AAC before they go poking their nose into playback of the other profiles. iTunes 4.6 slaughters the decoding of a castanets sample at 320kbps, and chokes on all of my Psy-Tel encoded VBR AAC.

So, waiting is the only thing I can do. Hope they will improve on it.

Almost nothing supports AAC Main profile. Even more so because it was obsoleted by the LTP profile.

Decoding speed is seriously lowered in return for a very modest efficiency gain.

FAAD can decode both Main and LTP profile but almost nothing encodes it correctly. (Neither does FAAC!)

I am currently working on a MPEG4 AAC encoder that supports both Main and LC profiles.. I think you are right about the Main Profile. Not only is it computationally expensive, it also requires 6 x channels x 672 x 4 bytes of memory to store its predictors' states..

My guess is that LTP is much better than Main Profile though I have not tried out the LTP profile yet..

Thanks for all your reply. And I'd like to know which profile is technically better, LC or LTP? (or Main? If you are willing to count it in)

Moreover, I think I'd better use LC profile currently. Actually, I use Nero AAC (LC) for most stuffs.

LTP is technically the best, but forget about it ever being widely supported.

I see. Thanks, Garf.