Lossless conversion of AAC to MP4

[aps]

Is lossless conversion of AAC to MP4 available? I can't find it.

-Anders

[Porcus]

Is lossless conversion of AAC to MP4 available? I can't find it.

MP4 is a container format that can contain AAC streams. Do you simply have a &*8220;raw&*8221; .aac file?

My solution is by way of ffmpeg and command line. Download Windows binary (i.e. .zip with an .exe in it). Then a command like

FOR %F IN (*.aac) DO C:\<insert path to ffmpeg.exe here unless you have it in your PATH variable>\ffmpeg.exe -i "%F" -acodec copy "%F.m4a"
will take every .aac file in current directory, and convert to .m4a (replace by .mp4 if you like) -- the -acodec copy part ensures it does not reconvert, merely re-encapsule the stream.
If you want to put this in a .bat file, replace the % signs by %%.


If you prefer GUI's, then look for YAMB or something like that.

[Porcus]

Not that this has anything to do with the original question asked many months ago, but:

There is no support in the claim that AAC is about half the size of MP3 (that is user-configurable) and certainly not that AAC is half the size of MP3 at the same quality. With modern lossy encoders there is no shortcut to halving filesize, except possibly at the very low end (way below 64).

Over at hydrogenaudio.org there are routinely arranged public blind tests. Of modern encoders, it is hard to tiebreak by quality anything at 140-ish bitrate (i.e. the 1/10 of CD). And, at the risk of overgeneralizing, anything at 96 beats anything at 64 beats anything at 48.