[PD] no more sound on iOS with biquad~ and libpd

Jack jack at rybn.org
Fri Jul 17 14:13:23 CEST 2015


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Thanx IOhannes,

First :
Isolate the biquad~ "stuff" has solved the issue (without [clip~ -1 1])

Secondly :
Adding a [clip~ -1 1] just before the [dac~] doesn't solve the problem.

Thirdly :
But I don't know yet where the problem comes : if a [clip~ -1 1] is
added after the biquad~ "stuff", it works, no crash.

I have to dig a little bit more...
++

Jack



Le 14/07/2015 16:53, IOhannes m zmoelnig a écrit :
> On 2015-07-14 16:11, Jack wrote:
>> Hello,
>> 
>> Jumping fast to certain coefficient (for frequency around 40/50
>> Hz and Q around 0.7) cut sound on iOS (iPad) when i use libpd (it
>> seems to be OK with MacOSX). I need to restart the iOS after. Do
>> you know what I have to do to solve this issue ?
> 
> provide a test-patch.
> 
> two ideas: - the quick jump causes some very high sample values.
> the iOS system limiter~ mutes the signal and takes ages to recover
> (too long to wait). a quick fix would be to use [clip~] just before
> the [dac~]s
> 
> - the quick jump might cause a NaN to be introduced in the signal 
> vector; due to the recursive nature of [biquad~] all successive
> samples become NaNs. no quick fix for this. try to get the sample
> values after muting. e.g. using [print~], or even just [env~]...
> 
> fmasdr IOhannes
> 
> 
> 
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