[linux-audio-user] Flac vs wavpack and float32 to pcm24 conversion tests

Paul Davis paul at linuxaudiosystems.com
Sun Mar 4 18:33:45 EST 2007

On Mon, 2007-03-05 at 08:37 +1100, Erik de Castro Lopo wrote:
> I would be **very** surprised if it was. For a normalised WAV file
> the maximum value would be 1.0 which will correspond to a pcm24 
> value of 0x7ffffff. 

i see no problem with that value, assuming you mean it represent 2^24-1.
do you?

> The float32 file could also contain a sample 
> with a value of 1/(2^25) which is smaller than the pcm24 value of
> 0x1. Hence, float32 -> pcm24 -> float32 is not lossless.

IEEE 32 bit floating point has 1 sign bit and 23 bits of mantissa. i
don't see how you can get 1/(2^25) out of that. the small representable
value with an effective non-unity exponent (i.e. ignoring the bias
stuff) is 1/(2^23), isn't it?

awaiting enlightenment ....

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