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

Did you synchronnize the cards via WordClock? Because if you did not,
you will inevitably run into issues due to clock drift.

On 08/02/2017 05:56 PM, Jörg Müller wrote:
> This is months old, but I have news to this topic.
>
> The suggested changes work and we have set up 11x16channel audio
> monitors. That is 176 speakers!
>
> However, running Jack is highly unstable, it crashes roughly every two
> minutes and causes a huge amount of XRuns even at buffer sizes like
> 16000. CPU is down at 5%, so that is not the issue. Jack runs without a
> problem when using just one card. However, we need to combine the three
> MADI-Cards via .asoundrc in order to eventually get to 768 channels.
>
> I have the jack logs here: https://pastebin.com/ke25cdXB
>
> Do you have any idea what could cause the issue?
>
> Best, Jörg
>
>
> Am 10.02.2017 um 14:15 schrieb Adrian Knoth:
>> 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),
>> PORT_NUM_FOR_CLIENT
>>
>> That should be it.
>>
>> Play a bit so it matches your setup. Feel free to send a patch.
>>
>>
>>
>> HTH
> 
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