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

[Brian Willoughby]

 > Hello FLAC list.
 >
 > As far as I know 24 bit FLAC support is broken.  It often doesn't
 > compress the audio at all, but instead stores the chunks as verbatim
 > type (although the FLAC format supports 24 bit).  Perhaps this is  
fixed?
 > If so, do let me know.

Hi Josh Green,

24-bit FLAC works perfectly, and has done so for years.  I regularly  
make live recordings in 24-bit and back them up after compressing  
with FLAC.  I sometimes files as small as 30% of the original because  
I record at conservative levels to avoid.  Also, if you screw up and  
put 16-bit audio samples in a 24-bit file, FLAC will still compress  
this to within 1% or 2% of what you get when compressing the 16-bit  
file.  FLAC 1.1.2 is what I have tested the most, and I'm not sure  
how long I've been running 1.1.4 so far.


 > I agree that perhaps 32 bit float/pcm isn't
 > entirely necessary when it comes to storing different qualities.  But
 > when wanting to preserve floating point audio, I would think it  
would be
 > a nice feature.

As I said, converting to 24-bit does preserve 32-bit float, unless  
standard audio practices are not followed and the data exceeds +/-  
1.0 samples.

 > I believe 32 bit floats have a precision of 23 bits
 > when the audio is +/- 1.0, so in theory that would mean that 24 bit
 > would have more precision but less dynamic range (if the floating  
point
 > range is outside of +/- 1.0).

No.  Floating point values are always normalized so that the most  
significant "1" bit is always in the same position.  Thus this bit is  
not stored.  So the 23 bits that are stored , plus the 1 bit that is  
assumed, both add up to 24 bits total.  32-bit float has the same  
precision as 24-bit integer.

 > The conversion to 24 bit would be a
 > problem in that case.

Well, yes, clipping is a problem whether you're playing the audio so  
you can listen to it, or you're converting to integer for any other  
reason.  That's why 32-bit is important for intermediate stages of  
modern DAW software.

Brian Willoughby
Sound Consulting