vmix-master/ folder and open the
index.html file in the Chrome browser.
The audio volume science is a little bit hard to understand and vMix in addition also makes it even more complicated by using different scales. Here is some background on the Decibel (dB) based scales (like "volumeThreshold"), the formulas how the scales can be converted, and some examples:
Scales:
Volume: 0 to 100 (used for UI volume bars, SetVolumeFade)
Amplitude: 0 to 1 (used for API audio bus meter, @meterF1)
Amplitude2: 0 to 100 (used for API input volume input, @volume)
Decibels: -oo to 0 (used in audio science)
Formulas:
Amplitude = Amplitude2 / 100
Amplitude2 = Amplitude * 100
Volume = (Amplitude ^ 0.25) * 100
Amplitude = (Volume / 100) ^ 4
Decibels = 20 * Math.Log10(Amplitude)
Amplitude = 10 ^ (Decibels / 20)
Examples:
==== METER (measured) =============== ==== CONTROL =============
Volume (%) Amplitude Decibel (dB FS) Volume (%) Decibel (dB FS) *
---------- ---------- --------------- ---------- ---------------
100 1,0000 0,00 100 - 18,00
95 0,8145 - 1,78 95 - 19,78
90 0,6561 - 3,66 90 - 21,66
85 0,5220 - 5,65 85 - 23,65
80 0,4096 - 7,75 80 - 25,75
75 0,3164 - 10,00 75 - 28,00
70 0,2401 - 12,39 70 - 30,39
65 0,1785 - 14,97 65 - 32,97
60 0,1296 - 17,75 60 - 35,75
55 0,0915 - 20,77 55 - 38,77
50 0,0625 - 24,08 50 - 42,08
45 0,0410 - 27,74 45 - 45,74
40 0,0256 - 31,84 40 - 49,84
35 0,0150 - 36,47 35 - 54,47
30 0,0081 - 41,83 30 - 59,83
25 0,0039 - 48,16 25 - 66,16
20 0,0016 - 55,92 20 - 73,92
15 0,0005 - 65,91 15 - 83,91
10 0,0001 - 80,00 10 - 98,00
5 0,0000 -104,08 5 -122,08
1 0,0000 -160,00 1 -178,08
0 0,0000 - oo 0 - oo
(*) for a usual incoming voice signal of -18 dB FS
Attention: Keep in mind that 100% of a Volume Meter corresponds to 0 dB FS, while 100% of the Volume Bar corresponds to the full incoming signal (usually about the target loudness of -18 dB FS for voice). So, if you attenuate by targeting a Volume Bar of 50%, you are reducing your incoming signal BY(!) -24 dB relative, and NOT TO(!) -24 dB absolute.