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Old 11th December 2004, 06:14   #3
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Join Date: Dec 2003
Posts: 21
HE-AAC (AACPlus) M4A files not playing back in WinAmp

I am trying to play back M4A files created with Nero 6 Ultra's HE-AAC (AACPlus) encoder. It seems that WinAmp will play back Nero's files ONLY if they are encoded using AAC LC and will "choke" (freeze/crash) if WinAmp 5.07 is launched to play one of these files. Attempted playback of an AACPlus M4A file causes WinAmp to play a short tone and then either hang or crash and ask you to send a problem report to Microsoft.

I am using WinAmp 5.07 Pro [Fresh Install] under Win XP SP 2 on a Dell Dimension 2400 2.4Ghz Celeron with the latest drivers for a M-Audio MobilePre USB sound card. This problem has been seen by other users as well, so I do not believe it is my system/configuration.

As AACPlus (HE-AAC) files are part of the the new MPEG 4 Audio standard and are becoming quite popular, I believe WinAmp should play them without the need for a 3rd party in_mp4.dll replacement plug-in. Also, since WinAmp does correctly support and play M4A files currently (normal AAC LC ones), it should not crash when presented with a M4A file in HE-AAC/AACPlus format. WinAmp doiesn't crash when presented with a MP3PRO file, but plays it in using the standrd MP3 decoder if the Thompson plug-in is not installed. The same should (at least) happen when playing back M4A AACPlus files, and WinAmp shouldn't crash/hang when playing them.

Since AOL/WinAmp has already paid for a license to use the Coding Technolgies AACPlus decoder, there is no reason to not use that decoder for playback of HE-AAC/AACPlus M4A files just the same way WinAmp currently using the Coding Technolgies AACPlus decoder for .aac files and .aac Internet radio streams.

WinAmp does correctly play AACPlus files without the MP4 container file (i.e. straight .aac files), but this does no good for .M4A files which are the standard packaging/file format for RealPlayer 10.5, iTunes 4.7, iPod, and other audio encoder/decoder software. Since iTunes and the iPod is widely rumoured to support AACPlus shortly, I think it would be nice for WinAmp to play back AACPlus/HE-AAC files in a .M4A container file without the need to find and download the replacement FAAD WinAmp plug-in. Thanks!

I have started a thread discussing this on and a Nero developer replied that it was bug in WinAmp that is causing this crash/bug for playback of HE-AAC/AACPlus M4A/MP4 files in WinAmp's decoder. Something about WinAmp using an older Dolby based decoder for playback of .M4A/.MP4 audio files in WinAmp, even though WinAmp/AOL has paid for, licensed and uses the newer (and properly working) Coding Technolgies AACPlus decoder for .aac files.

Take a look at that thread about this topic with WinAmp at:

[Edit --> DJ Egg]
Known issue.
Nullsoft in_mp4 is just a demuxer. The feature to send he-aac content in .m4a container to the aac+ decoder in in_mp3.dll has not yet been implemented (ie. it currently sends ALL aac content to the lc-aac dolby decoder in in_mp3). If you want this to be fixed/implemented sooner, please start by posting the crash error details and a link to a zipped .m4a file with he-aac content, so we can reproduce the problem and try get someone to fix it (again).

[Edit #2 --> DJ Egg]
This will hopefully be fixed for Winamp 5.1

Last edited by woeger; 11th December 2004 at 06:30.
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