[mythtv-users] [OT] m4a / aac audio support

Chris Petersen lists at forevermore.net
Mon Mar 29 12:34:01 EST 2004

> So it's definitely not proprietary.  But yeah on the same page it
> mentions the expensive and restrictive licensing as a con.  So what's
> the difference?  Just trying to understand the issue, not saying you're
> wrong.

It's open in the sense that anyone can get at the encoder/decoder codec,
source, binary, etc. (unlike something like realmedia or wmv, which is
closed and you couldn't really get a copy of the source code, and thus
would have to reverse engineer).  But the code is still patented, so in
order to legally use aac, you have to pay the fee.  This is the same as
with mp3, except that fraunhofer has traditionally overlooked software
encoders, and has waived the fees for software decoders.

MPEG is a standard, but it's a patented standard, approved by an
industry group, and all of the variants have some sort of licensing fees
or agreements associated with them.  Those that are free are not
free-as-in-speech, which is why groups like Xiph and the FLAC people are
around to make truly-free media formats.  Unfortunately, they don't have
the corporate backing necessary to make much headway in the industry
(although ogg vorbis is growing in popularity), and the fact that the
"average user" doesn't know that .mp3 .rm and .wma are anything other
than different names for "those emm pee three audio files" makes it very
hard to explain why a new/free codec is so important (I will admit that
apple *has* done a good job getting people to understand the difference
between aac and mp3 audio, though).


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