Soundfile read/write wav is not symmetric with default arguments about python-soundfile HOT 3 OPEN

This is the unfortunate reality of integer numbers. The lowest possible 16-bit number is -2^15, but the highest possible is 2^15-1. When dealing with float inputs, you have to apply some scaling, and there is no correct answer.

• Do you scale positive numbers differently from negative numbers? There will be (tiny) discontinuities at the zero crossings.
• Do you scale to 2^15-1? Then you lose one value for negative numbers.
• Do you scale to 2^15? Then you lose one value for positive numbers.

There's no right answer. But in reality, the differences between these is imperceptible.

Soundfile does not implement this, but merely passes the data on to libsndfile, which does the transformation.

If you need a perfect float representation, you could always use a native float format, such as MAT5, or (IIRC) Flac or WAV with the FLOAT subtype.

from python-soundfile.

Yes. I understand that. I was mostly wondering why the scaling is different on write and read, but it is a problem with libsndfile then?

At least, this is the behavior I observe:

• Write: different scaling factor for negative and positive values
• Read: Equal scaling factor for all values

Anyhow, I understand that I'm complaining about a 1/2**15 max quantization error vs a1/2**16 max error, and these differences, as you say, are probably imperceptible.

from python-soundfile.

The problem is not that read and write are different, but that +1 is not representable. If you use values <1, it should be symmetric.

from python-soundfile.