Only the first Aftertouch value is handled

[Florob]

I'm trying to use Helm (standalone) with polyphonic aftertouch. It seems that only the first aftertouch event received after the note on is actually handled. Following changes to the aftertouch value don't seem to affect the assigned control.

[mtytel]

Looking into this. My keyboard with aftertouch unfortunately is in storage at the moment..

[mtytel]

Where did I put my keyboard with aftertouch?? :|

[mtytel]

Well I finally found my keyboard with aftertouch and it works with my setup on GNU/Linux and OSX. Haven't tried Windows yet.
Could you send me what OS you're on and what keyboard you're using? Have you gotten aftertouch from that keyboard working with other synthesizers?

[Florob]

I'm using an up to date Arch Linux, with a Miselu C.24 keyboard.
In my experience there is a certain lack of synthesizers supporting polyphonic aftertouch, so technically no. However, I have verified that events are send using amidi -d:

90 48 05
A0 0C 05
A0 0C 1A
[...]
A0 0C 03
90 48 00
90 4C 01
A0 10 01
[...]
A0 10 00
90 4C 00

Now, having looked at those bytes in some detail, I noticed that the key byte send with the Aftertouch events is different from the note byte send with the Note On events. The Aftertouch key is a one-to-one mapping to the physical keys, while the note changes with octave shifts. If I shift the octave down far enough that the note byte equals the key byte everything works as intended. I still find it strange that the first of the Aftertouch events per note appears to be handled though.
I have not been able to determine whether this behaviour is compliant with the MIDI specification. If you think it isn't/I should complain to Miselu instead, feel free to close this bug.

[mtytel]

The way aftertouch is implemented in Helm is that it takes the velocity value as the first value. I think I did this because defaulting to 0 gave some strange behavior if you slammed down a note.

I'm not sure why you're getting that byte readout, but I know some keyboards have only monophonic aftertouch, some have polyphonic aftertouch and on some keyboards you can switch between them in the settings. The aftertouch in Helm is only polyphonic I believe, so if yours is setup for monophonic that might be the issue.

[mtytel]

Closing because it's working for me and other people haven't run into this issue.
Probably could make it more compatible with more keyboards/control interfaces but I can't afford to buy a bunch of interfaces.