How to convert YAMAHA digital mixing console fader value to MIDI

Question

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)

Answer 1

I'm interested on how did you convert Yamaha mixing fader value > Midi value? I will try to do a module on max for it, but i'm not a midi expert so if you have help for me it would be great.

Answer 2

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.