Re: [ecasound] using copp-set with controllers

From: Adam Linson <adam.linson@email-addr-hidden>
Date: Sat Sep 03 2005 - 13:49:07 EEST

Hi again,

On 9/1/05, Kai Vehmanen <kvehmanen@email-addr-hidden> wrote:
> 1) can you reproduce the test with:
> - run qmidicontrol; position the 1st slider at 50%
> - ecasound -i null -o rtnull -epp:50 -km:1,0,100,1,1 -Md:alsaseq,128:0 -c
> - monitor with 'ctrl-status'; there shouldn't be any
> jump in controller values when you start moving the qmidicontrol sliders

you are right -- with your test above, everything works exactly as expected!

> Hmm, could this be a problem with the MIDI-CC? What are you using for
> control?

I guess my problem is indeed my controller, a doepfer "pocket dial".
this is what doepfer has to say about it:

"the POCKET DIAL does not "know" the absolute values of the parameters
but transmits only inc[rement]/dec[rement] data to the
device/software. Only devices that features the data feedback or
inc/dec control should be controlled by POCKET DIAL".

here is some more detailed technical info from their docs:

Pocket Dial transmits Increment / Decrement Data

In this case Pocket Dial does not "know" the absolute value of the
parameter but transmits only the information data increment
(abbreviation: inc) or data decrement (abbreviation: dec).
Unfortunately there is no MIDI message available "increase data of
MIDI Controller XX" or "increase data of MIDI Controller XX". There is
only a general Data increment (Controller #96 decimal, resp. #60
hexadecimal) and Data decrement message (Controller #97 decimal, resp.
#61 hexadecimal) available. The third byte of these messages is - as
far as we know - not used so far. In the MIDI spec we found no
statement concerning this byte. Remember: each MIDI control change
message consists of 3 bytes. We want to solve this problem by "hiding"
the controller number, to which the inc/dec is related to, in the
third byte of these messages. This modified inc/dec messages would
enable to increase or decrease the value of a specific MIDI
controller. We hope that other companies will agree to this proposal
and adjust their software/hardware to this amendment of the MIDI Data
increment/decrement message (controller #96/97).

The "new" MIDI messages are:

    *Controller Increment: BnH 60H xxH
    *Controller Decrement: BnH 61H xxH

with n = MIDI channel (0...F) and xx = MIDI Controller No (00...77H,
78H...7FH is reserved for Channel Mode Messages). H means hexadecimal

Doesn't sound too trivial. Oh well, guess it's time for me to start
using a different controller.

Thanks again for the code tweak. Just to clarify to the list: the new
feature works perfectly!


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Received on Sat Sep 3 16:15:04 2005

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