[Flac-dev] Re: FLAC: same features as WavPack

[Brian Willoughby]

Hi Justin,

FLAC is not just a specification.  FLAC is both a specification and a  
reference implementation.

I recall that the sample bits must be low-aligned, not high-aligned  
as I would have normally assumed.  I haven't looked back at the spec  
or my source code to confirm my memory, though.

I've just been able to reproduce the problem with a file from Josh  
Green.  I have yet to analyze the samples, but the problem is not  
specific to AIFF or WAV formats.  Unfortunately, this indicates that  
both libFLAC and the flac command-line tool are broken, so there  
isn't any way to look at the flac command-line source to find a way  
around the problem.

Sorry to come across as defensive.  I guess I let the fact that I've  
sent a hundred different 24-bit files through FLAC without ever  
seeing this problem lead me to assume that it was a crusty old issue  
which hadn't been reproduced.  From my point of view, it was starting  
to sound a lot like a rumor.  But now we may be getting to the bottom  
of this.

Brian Willoughby
Sound Consulting


On Mar 30, 2007, at 15:00, Justin Frankel wrote:

To clarify, I am one of the REAPER developers.

To say that FLAC itself is not broken is sort of meaningless--FLAC  
itself is just a specification. So yes, it is just libFLAC that is  
broken. I have spent QUITE a bit of time trying to sort out why it  
fails on 24 bit mode.. If there are some specific alignment  
requirements of samples, please point me to the documentation of  
them, but we have experimented with many-- and indeed we aren't doing  
things TERRIBLY wrong, as it does at least preserve the samples.

Perhaps it's just a little endian or OS issue. You don't need to be  
overly defensive of FLAC--this isn't a criticism, it's just a request  
for clarification/fixing of an issue that a lot of people seem to  
experience.

-Justin