A Python module for FL Studios MIDI-scripting API that make volume conversions between dB and float
You can set the volume in the mixer in your scripts with FL Studio's MIDI-scripting API with mixer.setTrackVolume. This method accepts a float value between 0 and 1 as input. So how can you set the volume to -4.5 dB for example? Well, you'd need to convert it from dB to float first. Something like float_value = pow(10, -4.5 / 20), right?
No. The reason is that FL Studio uses a non-linear volume scale.
In my attempt to solve this, I made a map of the dB values and wrote some code that fetches the nearest values from a lookup-table. It gets the job done with perfect accuracy (when converting from dB to float) unless you try to convert ridiculously low dB-values below -70dB, where the error-rate will increase really fast. The reason for this is that the volume scale in FL Studio loses a lot of its resolution near the bottom end, i.e. it's not possible to set any exact values when the values approach near silence (who would need that anyway?). Nevertheless, I have mapped all the nearest values that mixer.setTrackVolume can set, all the way to the bottom. In that regard, the conversions are as perfect as they can be made.
Please note that when converting the other way around (from float to dB), the accuracy will suffer a bit due to the fact that the conversion uses the nearest value it can find in the lookup-table. The result will be pretty close (within 0.1 dB) but not as perfect as when converting from dB to float. You can circumvent this by using mixer.getTrackVolume and give it the optional argument to return the result in dB instead.
Copy the file volume.py to the same folder as your own script resides in. Open your script in a text-editor and import the flstudio-volume-converter module. The import-line can be added anywhere in your script as long as it's somewhere at the beginning. I recommend putting it together with the rest of FL Studio's MIDI scripting API imports.
To import flstudio-volume-converter, add this line to your script:
import volume
It gives you access to 3 methods:
| Method | Argument | Result | Documentation |
|---|---|---|---|
| db_to_fl | decibel_value | float | Converts the given decibel_value to a float value between 0 and 1. |
| fl_to_db | float_value | decibel | Converts the given float_value to a decibel value between -100 and 5.6. Note that this will return the nearest dB value which means that the result will be within a 0.1 dB margin of error, i.e. it's not perfect. If you need perfect accuracy, use mixer.getTrackVolume(track_number, 1) to get the volume in dB from the desired track. |
| add_db | float, decibel | float | Takes a given float value and adds or subtracts the given amount of decibels from it. A positive decibel value will be added, a negative value will be subtracted. The result will be within a 0.1 dB margin of error. |
(requires that the mixer module from FL Studios MIDI scripting API has been imported.)
track = 1
volume_in_float = volume.db_to_fl(-4.5)
mixer.setTrackVolume(track, volume_in_float)
Result: Track 1 in the mixer will be set to -4.5 dB.
value_in_float = mixer.getTrackVolume(1)
converted_to_db = volume.fl_to_db(value_in_float)
print(converted_to_db)
Result: The volume of track 1 will be printed as a dB value.
value_in_float = 0.8
added_volume = 0.5
new_value_in_float = volume.add_db(value_in_float, added_volume)
Result: new_value_in_float will still be a float value but will have 0.5 dB added to it.
value_in_float = 0.8
subtracted_volume = -0.5
new_value_in_float = volume.add_db(value_in_float, subtracted_volume)
Result: new_value_in_float will still be a float value but will have 0.5 dB subtracted from it.