[Flac-dev] floating point

[Didier Dambrin]

Hi,

I've tried to find info about unofficial 32bit float support in FLAC, and found several conversations. 
Most of them were talking about a 24bit limit, but from the manual I guess that this limitation is gone, as it supports up to 32bit integer.

So my question is, what would be the best way, or what is a common way to FLAC-encode floating point audio?


The first idea is obvious, we have a 32bit float, FLAC supports 32bit integer, and it's lossless. So I'd just make it encode 32bit float, it's lossless afterall. 
2 problems, first I would suspect it wouldn't encode very well, since the data wouldn't be "audio" anymore, right? It would be like trying to FLAC-encode random data. 
So I tried FLACing white noise, and comp ratio was pretty poor, confirming this. Interestingly, it still did a better job than ZIP!
The second problem would be that no other tool would read them correctly anyway.


The second idea is to truncate & use it as a lossy encoder, which can be "audibly lossless" anyway. But what's a common practice here?
I would be tempted to leave 1 bit of headroom above 0dB, or maybe 2 bits.  Normalizing before encoding could be an option, but the gain would then have to be inserted in a tag. 
& finally, what bit depth? 24? 25, 26? 32? 
I know there's no right answer, just asking if there are common practices.


Thanks.
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