[Jack-Devel] Cannot combine audio devices with more than 64 channels

Adrian Knoth adi at drcomp.erfurt.thur.de
Fri Feb 10 14:15:06 CET 2017

On 02/08/17 18:16, Jörg Müller wrote:

> jackd: ../linux/alsa/JackAlsaDriver.cpp:122: virtual int
> Jack::JackAlsaDriver::Attach(): Assertion `fCaptureChannels < 256'
> failed.
> Aborted (core dumped)
> The corresponding cpp-file at that line compares against a variable
> called "DRIVER_PORT_NUM", which is a constant defined in
> "common/JackConstants.h" on line 53 on the github repo. Could that be
> the problem?

That's absolutely the problem, but the limit is arbitrary. Feel free to
recompile jackd2 with changed constants in JackConstants.h.

I guess you need to tweak a bunch of other values as well.

PORT_NUM, PORT_NUM_MAX, DRIVER_PORT_NUM (that's per direction),

That should be it.

Play a bit so it matches your setup. Feel free to send a patch.


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