[flac-dev] Supporting 32 bit data

Martijn van Beurden mvanb1 at gmail.com
Sat Sep 26 01:36:11 PDT 2015


Op 26-09-15 om 09:22 schreef Erik de Castro Lopo:
> Had two inial impressions:
>
> * Would adding this break brackwards compatibility too badly? Obviously
>    decoding of 32 bit encoded data would not work with older versions of
>    flac.

Probably not. I know that Josh at some point added a second 
residual coding method (rice2) to support 24-bit, but that only 
broke backward compatibility for 24-bit files back then.

> * This is nuts. 24 bits has a dynamic range of ~140dB which is roughly
>    the difference between a quiet whisper in a quiet room, to the sound
>    of a jet engine at 10 meters. Surely that is enough?

Yes, this is nuts. First, 24-bit is already overkill, as there 
is no hardware (ADC or DAC) that can handle more than 120dB of 
dynamic range anyway. There probably never will be hardware that 
can handle the full 24 bits, because at this point that hardware 
is already pushing the boundary of thermal noise. Second, most 
32-bit material is 32-bit float, and that is something the FLAC 
format can't handle. I really wonder why anyone would have 
32-bit integer material anyway.



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