MIDI learn should support a single knob for opposing functions (e.g. track select)

[Daniel Schürmann]

Dear devs,
I'm wondering if this feature can be added: when learning MIDI from a controller, I would like to scroll up/down the tracks with one potentiometer/encoder. Unfortunately the MIDI learn feature only tracks the CC and not the value increment/decrement, thus I cannot use one pot/encoder for scrolling up/down, but I have to assign two pots or two push buttons (which are too slow to scroll through the list).

If this cannot be done by editing some script/mapping file, I would try add the fix from the source, but I need a hint where to look for.

Best regards

[Daniel Schürmann (daschuer)]

Created from: https://answers.launchpad.net/mixxx/+question/253303

[Daniel Schürmann (daschuer)]

Is it an endless knob, you trying to map?
What is the console output if you start Mixxx with
mixxx --controllerDebug
and turning the knob in both directions?

The mapping would look like that using a RMX2 effect knob:

<control>
 <group>[Playlist]</group>
        <key>SelectPrevTrack</key>
        <status>0xB0</status>
        <midino>0x54</midino>
</control>
<control>
 <group>[Playlist]</group>
        <key>SelectNextTrack</key>
        <status>0xB0</status>
        <midino>0x55</midino>
</control>

[Leodardo (leodardo)]

Thanks for getting back quickly.
My controller is a M-Audio AxiomPro49, and I'm prototyping a custom microcontroller based MIDI controller where I will add an endless encoder.

By opening mix in debug mode I realized my (physically) endless knob was (virtually) actually not endless, as the controller mapped it to a virtual CC knob with vals ranging 0x00-0x7F, so the scrolling would in any case come to an end. Silly me!

The solution is to assign the knob a different type from the MIDI controller itself: Edit -> Control -> Type: SingleStep-/+

Now the knob outputs two different commands whether it is incrementing or decrementing:
Debug [Controller]: "MIDI status 0xB0 (ch 1, opcode 0xB), ctrl 0x61, val 0x00"
Debug [Controller]: "MIDI status 0xB0 (ch 1, opcode 0xB), ctrl 0x60, val 0x00"

With the two different CC for up and down. In Mixxx I just done again a MIDI learn and it works like a charm!
So everything's ok in Mixxx. You just have to make your knob work the right way.
Regards

[Daniel Schürmann (daschuer)]

Nice to read this bug is fixed. Can you edit the title of this bug, that it helps others and set it to invalid?
Thank you.

[Sean M. Pappalardo (pegasus-renegadetech)]

Leodardo: Can you also test where the knob uses the same control # for both directions but changes only the value? e.g. 0x3F for backwards and 0x41 for forwards. This is how most endless knobs work and I want to make sure it works for you with learning as well.

[Sean M. Pappalardo (pegasus-renegadetech)]

...or is that what you did originally? If so, I would consider this still an open bug since the learning should be able to handle that case.

[Leodardo (leodardo)]

Just to be clear, as you ask I'm sending two MIDI commands, same CC,
different value:
Debug [Controller]: "MIDI status 0xB0 (ch 1, opcode 0xB), ctrl 0x19, val
0x7E"
Debug [Controller]: "MIDI status 0xB0 (ch 1, opcode 0xB), ctrl 0x19, val
0x7F"

With the first I tell mixxx to scroll down, with the latter to scroll up.
The learning learns the first as scroll down, then when I attempt the
learning for the scroll up, it deletes the first one, I can see it from the
XML. I guess the logic is to delete older learnings for the same <midino>
or CC.

I think the logic should be changed for controls that do not require a
value: unlike faders, a "scroll down" or "switch view" need only sense a
CC+value couple. However I think there are cases where you only need to
watch the CC and cases where you exactly want to map a command to CC+value.
But that's my 50 cents.
Regards

2014-08-20 17:57 GMT+02:00 Sean M. Pappalardo <email address hidden>:

> ...or is that what you did originally? If so, I would consider this
> still an open bug since the learning should be able to handle that case.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1358844
>
> Title:
> Track scrolling with endless knob: controller setup
>
> Status in Mixxx:
> Invalid
>
> Bug description:
> Dear devs,
> I'm wondering if this feature can be added: when learning MIDI from a
> controller, I would like to scroll up/down the tracks with one
> potentiometer/encoder. Unfortunately the MIDI learn feature only tracks the
> CC and not the value increment/decrement, thus I cannot use one pot/encoder
> for scrolling up/down, but I have to assign two pots or two push buttons
> (which are too slow to scroll through the list).
>
> If this cannot be done by editing some script/mapping file, I would
> try add the fix from the source, but I need a hint where to look for.
>
> Best regards
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mixxx/+bug/1358844/+subscriptions
>

[Sean M. Pappalardo (pegasus-renegadetech)]

We should make the MIDI learn support the case where a single knob can be used for two opposing functions if it gives different values for each. Marking this as new until me or another dev has a chance to test to see if this already works in latest master.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/7557