Converting .m4a to .wav?

dowhatnow · Post by **dowhatnow** » Mon May 28, 2007 2:39 am

How is this done? I'm not at all sure.

Willen · Post by **Willen** » Mon May 28, 2007 9:18 am

You can use Winamp to convert the .m4a file to a .wav, the same way you would use it to convert a mp3: http://www.animemusicvideos.org/guides/ ... dio3c.html.

dowhatnow · Post by **dowhatnow** » Mon May 28, 2007 3:14 pm

Awesome. Thanks.

Now the more difficult question: How do you extract a .m4a stream from a .mov? I tried opening it in VirtualDub, but it just doesn't. It tells me "Cannot detect file type of 'filepathandname.mov'" whenever I try to do so.

Willen · Post by **Willen** » Tue May 29, 2007 5:52 am

Opening it with DirectShowSource() via AviSynth and VirualDub(Mod) should work. Ex.: DirectShowsource("C:\path\video.mov").

The audio will be listed under Streams > Streams list as an AVI audio stream (PCM) which should allow you to use the Save WAV function.

Unfortunately, I'm unable to tell you how to extract the .m4a (AAC) audio file directly.

Qyot27 · Post by **Qyot27** » Tue May 29, 2007 2:18 pm

dBPowerAMP Music Converter (even the new MP3-crippled versions, I'm sure) will decode from MP4 - that includes M4A - and AAC* files to Wave, as long as you've installed the proper plugin from their website.

*provided the AAC file has ADTS headers, that is. Another note: I think it also only works when the MP4 file contains AAC, not MP3.

It's possible to extract AAC streams from MOV (or MP4) files with MP4Box (or YAMB, if you prefer - it's just an MP4Box frontend, makes things simpler - just remember to get the 1.6 version of YAMB, I feel the newer one is actually less intuitive).