Bit depth weirdness. Is this a bug and if it is, does it matter?

IXix · 06-21-2021, 01:10 PM

I don't know if this is bug and I don't know if it actually makes any difference since I can't hear it but it looks weird, so maybe it's bad. If it's unintentional distortion maybe it might get picked up and amplified by further processing leading to unwanted results? If it's not a bug, I'd certainly be interested to hear an explanation of what's going on.

For the sake of a demo, in place of audio I have a JS noise gen producing a signal at 64bit. TB_Barricade truncates the signal to 32bit as shown by the bitmeter on the item and the track. Watch what happens to the track bitmeter when I enable the item volume envelope...

Any thoughts?

edit: Oh, Win10, REAPER 6.29 and all plugins used are 64bit

nofish · 06-21-2021, 03:49 PM

Interesting but no idea what's going on there.
Curious how this (hopefully) resolves.
(Not a helpful post I know. :P)

schwa · 06-21-2021, 06:49 PM

It's not really a bug. It's caused by a sort of floating point quirk in how a fader-scaled volume envelope set at unity is handled. The low-bit information is not distortion, it's a very tiny amount of gain (about 0.000000000001 dB).

IXix · 06-22-2021, 02:00 AM

Quote:

Originally Posted by nofish

(Not a helpful post I know. :P)

LOL

Quote:

Originally Posted by schwa

It's not really a bug. It's caused by a sort of floating point quirk in how a fader-scaled volume envelope set at unity is handled. The low-bit information is not distortion, it's a very tiny amount of gain (about 0.000000000001 dB).

Thanks Schwa. I thought it was probably nothing much being down in those bits, but I thought it looked weird enough to justify asking a question. Certainly had me scratching my head for a while, wondering what was going on as I tried to "master" some recordings!

Nothing to see here people, move along...