[SOLVED] How to convert YAMAHA digital mixing console fader value to MIDI

How to convert YAMAHA digital mixing console fader value to MIDI

I'd like to convert YAMAHA digital mixing console "fader value"(db) to MIDI data.

I understand that yamaha mixing console use two "MIDI control change message"(fader L, fader H) to expressed each fader in high resolution.

However, I don't understand how to "fader value"(db) mapping those message. I captured that message, but did't find out that rules.

Is there calculatin method or mapping table ?

Please could you help me.

Capture Data: ch 1 fader

0.0db
RECEIVE    | ENDPOINT(AUDIO4c DIN) TYPE(CONTROLCHANGE) CHANNEL(1) DATA1(1) DATA2(102)
RECEIVE    | ENDPOINT(AUDIO4c DIN) TYPE(CONTROLCHANGE) CHANNEL(1) DATA1(33) DATA2(119)

0.15db
RECEIVE    | ENDPOINT(AUDIO4c DIN) TYPE(CONTROLCHANGE) CHANNEL(1) DATA1(1) DATA2(103)
RECEIVE    | ENDPOINT(AUDIO4c DIN) TYPE(CONTROLCHANGE) CHANNEL(1) DATA1(33) DATA2(39)

0.45
RECEIVE    | ENDPOINT(AUDIO4c DIN) TYPE(CONTROLCHANGE) CHANNEL(1) DATA1(1) DATA2(104)
RECEIVE    | ENDPOINT(AUDIO4c DIN) TYPE(CONTROLCHANGE) CHANNEL(1) DATA1(33) DATA2(7)

That Console setting is default:
- Control change number 1 to "fader H Input CH 1"
- Control change number 33 to "fader L Input CH 1"
- Mode: SINGLE / TABLE
Console: YAMAHA QL5
Capture Application: Protokol(https://hexler.net)

Solution

This is a 14-bit controller (see p. 17 of the MIDI specification); the actual controller value is MSB*128+LSB.

So the mapping is as follows:
0.00 -> 13175
0.15 -> 13223
0.45 -> 13319

This is perfectly linear. So CC = 13175 + 320 * dB, and dB = (CC - 13175) / 320.