[Flac-dev] Re: FLAC: same features as WavPack
brianw at sounds.wa.com
Thu Mar 29 12:53:43 PDT 2007
> 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
> 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
> 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 +/-
> 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
> 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.
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