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API - Volume settings - Quick question about this
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NewsworthyVision  
#1 Posted : Wednesday, October 21, 2020 9:04:34 PM(UTC)
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Hello all, I'm finding that the volume settings put out by the API are done on a zero to one scale, but I'm finding that it is maybe Logarithmic as well?

Example, putting out a 0dBu signal via NDI shows 1.00, but then a -8dBu signal shows 0.5, a 50% drop. (Which for a logarithmic audio scale is correct I think?)

However within vMix itself, it doesn't show a drop of 50%, but a marginal drop only.

I don't suppose we could possibly get the API to show a dBu signal rather than a decimal scale? Or, does anyone have a method using Javascript or similar to convert to a Logarithmic scale from this basic 0-1 system?

Thanks all!

Nick
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elgarf  
#2 Posted : Thursday, October 22, 2020 1:23:14 AM(UTC)
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NewsworthyVision  
#3 Posted : Thursday, October 22, 2020 1:29:35 AM(UTC)
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Would you believe I discovered this moments ago too... Feeling a bit stupid today.

Thanks elgarf.
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NewsworthyVision  
#4 Posted : Thursday, October 22, 2020 2:50:07 AM(UTC)
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For anyone else looking to do this, here is how I managed to convert it from Volume to Amplitude to match dBu in Javascript:

User guide: Volume = (Amplitude ^ 0.25) * 100
Javascript: const volume = ((input._attributes.meterF1 ** 0.25)*100).toFixed(2);

User guide: Amplitude = (Volume / 100) ^ 4
Javascript: const amplitude = ((input._attributes.volume / 100) ** 4).toFixed(2);
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thanks 1 user thanked NewsworthyVision for this useful post.
ryanlehms on 4/27/2021(UTC)
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