View Single Post
Old 04-07-2017, 11:32 AM   #34
Robert Randolph
Human being with feelings
Robert Randolph's Avatar
Join Date: Apr 2017
Location: St. Petersburg, FL
Posts: 775

Originally Posted by bezusheist View Post
here are 3rd party stats showing what happens with the normalizing process...
the process was:
generate 0 dBFS source file @ 64 bit float (render)> clip symmetrically to -0 dBFS (render)> gain down 50% to -6.02 (render)> item processing "normalize items" (render)
all files were rendered at 24 bit integer (no dither).
i have tried this same test using all 64 bit float files as well, and the results are basically the same. (normalizes to same value, not 0dBFS)

afclip stats

source file
1 ch, 44100 Hz, 'lpcm' (0x0000000C) 24-bit little-endian signed integer
-- no samples clipped --

SoX stats

source file:

DC offset 0
Min level -8388607
Max level 8388607
Pk lev dBFS -0.00

attenuated 50% (spl0*0.5)

DC offset 0
Min level -4194304
Max level 4194304
Pk lev dBFS -6.02

normalized in Reaper

DC offset 0
Min level -8380219
Max level 8380219
Pk lev dBFS -0.01*

*actual value is more like -0.00869...+/- dBFS

i attached all of the test files just to "properly" document this with some actual "evidence".

edit: huh...i think i actually just figured out what's going on, but i'll wait to hear from a developer or someone first..
I can replicate this.

However, I'm not sure that the value of fixing this is worth it unless it's some very obvious fix for the developers.

edit: Information:

sox 2_pulses_0dBFS_sym_clip_24bit.wav -n stats
Samples read: 132300
Length (seconds): 3.000000
Scaled by: 2147483647.0
Maximum amplitude: 0.999000
Minimum amplitude: -0.999000
Midline amplitude: 0.000000
Mean norm: 0.000015
Mean amplitude: 0.000000
RMS amplitude: 0.003884
Maximum delta: 0.999000
Minimum delta: 0.000000
Mean delta: 0.000030
RMS delta: 0.005493
Rough frequency: 9925
Volume adjustment: 1.001
Audio/DAW stuff, Woodworking, Programming and more... new posts every weekend.
Robert Randolph is online now   Reply With Quote