any free windows-based aac player?

Winamp + plugin, Foobar2000.

CoreAAC 1.0b3 DirectShow filter allows AAC to be decoded in any DirectShow based player.

how about free aac encoders on windows platform?
i just find out my aac file is not compliant to mpeg-4 aac standard, weird......

DBpowerAmp

Is there a decent plugin for WMP9 yet? I tried one (can't remember what it was) but it basically only allowed playback. Seeking, tags, media info etc. were all nonfunctional.

Yup, The best WMA support around.

I've recently added playback for windows to faad.exe which I believe is likely to be added to the CVS soon. I sent the source to Menno about a week ago. If you want a version to use now, it may differ slightly from what ends up in the CVS, you can download form here: http://homepage.ntlworld.com/jfe1205/faad.zip

If you want a GUI based player, aacDECdrop from Rarewares has decode to file and playback.

I just download the easy audio software to evaluate
and i find that the plugin for winamp cannot play aac or mp4 files produced
quicktime can play mp4 files, not aac files

and i find that the bitstream of both formats are not quite the same as what i read in mpeg standard, at least, i cannot see the sync word (FFF) at the start...
anyone can explain that to me? thx

AAC with any DS player (including WMP ):
* impossible, AFAIK.

MP4 with any DS player (including WMP ):
* 3ivx + CoreAAC.

AAC with Winamp:
* nothing to do (with 2.92 or better);
* in_aac.

MP4 with Winamp:
* in_mp4 (with 2.92 or better);
* in_mp4 + in_aac.

EDIT:
Typo.

It is possible, if someone comes up with a filter with file reading routines for AAC.

correct, somebody had to write an AAC source filter for DirectShow .....

Why not Foobar2000? Its a great player with solid MP4 support.

It's being mentioned at the second post.