[geoff]

alex reznick wrote:
Hi everyone

I converted the same file from 32 bit to 16 bit twice, repeatedly,
using the same dither and noise shaping, and it is quite consistent:

1) both files are NOT identical when the conversion is done in Cool
Edit Pro and Samplitude - over 12 million differences, and the delta
file looks like continuous broadband noise at -59.679 dB in Samplitude
and -78.268 dB in Cool Edit Pro

2) both files ARE identical when the conversion is done in Izotope RX

Does this mean that some programs inject randomized noise, and others
non-randomized? But then if randomization is the case, why does the
delta file show the difference in noise levels that is consistent from
pair to pair comparison?

I repeated conversion 8 times in Cool Edit, and the delta between 1 &
2, 3 & 4, 5 & 6, 7 & 8 takes is always -78.268 dB.

Can anybody explain what is going on here?


Whatever form of dither each uses, the dither waveform may start at a
difference part of it's cycle per conversion, so results will differ.

Presumably Izo uses something non-random, or 100% repeatable.

Cool Edit really is a bit ancient in terms of processing 'vintage'.

geoff