[PD-dev] [PD] wierd feedback popping with pd/freebob/jack/rt

[Rich E]

Hi IOhanens,

I moved this thread from the pd-list, since it is now only discussing pd's
audio jack in c.

Did you ever find time to look at s_audio_jack.c again?  I suspect it is a
freebob -only problem, but I have only experienced it in pd.  Somehow the
buffer alignment is getting knocked off track - making JACK_NUM_PORTS
smaller only seems to help this, but problems still arise when a big cpu hit
occurs.

It is also curious that audacity can effectively reset the audio buffers
coming from pd (or summed from both most likely) when it starts, but this
cannot be done from pd.  With JACK_NUM_PORTS > 512, pd even starts with
audio residue.

Maybe I should file a bug or move this question to the jack list..

regards,
Rich

On Wed, May 28, 2008 at 11:37 PM, <zmoelnig at iem.at> wrote:

> Quoting Rich E <reakinator at gmail.com>:
>
>  After more testing...
>>
>> With pd compiled with "JACK_NUM_PORTS 256", audio runs fine at first, but
>> if
>> the cpu gets a big hit, like when I open a soundfont in [fluid~], the
>> audio
>> falls behind and I get the pops/clicks again.  If I compile pd with
>> "JACK_NUM_PORTS 32", this doesn't appear to happen; [fluid~] does its
>> thing,
>> the gui freezes for a couple seconds, but the audio is fine afterwards.
>>
>> Hopefully this hints at what the problem really is.
>>
>
>
> no, unfortunately this does not make sense at all.
> NUM_JACK_PORTS is only used for sizing arrays properly and setting the
> maximum possible numbers of channels Pd can use. as the default number of
> channels is still 2, jack should actually not notice anything about this
> parameter.
>
> nevertheless, i will re-think....
>
> (but i really need at least 64 channels, most likely more; this was the
> main motivation to start writing the entire patch...)
>
>
> fgmads
> IOhannes
>
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