[PD] Maybe I'm pushing dynamic object creation too far

[Phil Stone]

Ed, I don't know if anecdotal confirmation will help you here, or just 
make you more frustrated, but I've noticed that I get more dropouts 
using Jack as opposed to portaudio (OS X) for the exact same 
processor-load.  This has caused me to switch back to portaudio.  Does 
anybody have any idea why this might be?


Phil Stone
www.pkstonemusic.com


On 2/2/11 3:25 PM, Ed Kelly wrote:
>> On 2011-02-02 01:00, Ed Kelly wrote:
>>> I get dropouts, regardless of the jack buffer size/buffers number. Is this
>>> because the dynamic creation of a new object interrupts the pd audio stream?
>> If
>>
>>> so, can this be alleviated - 1. is it a GUI problem (and will pd 0.43 fix it)
>>> and 2. if so, can pd -nogui sort it out?
>> the problem most likely comes from the DSP graph being continuously rebuilt.
>> the only things you can do for now is:
>> - - try to reduce rebuilding of the DSP graph as much as possible.
>> needeless to say that you shouldn't dynamically create objects that are
>> not needed.
>> more interesting is that e.g. creating 3 objects while audio is running,
>> will re-caculate the DSP graph 3 times. even if this happens in 0
>> logical time. so i you know you are going to schedule several
>> dynamically created objects "at once", turn audio off before and turn it
>> on again after you do the actual creation.
> Dammit!
> Only one at a time, but they are tables of perhaps 300000 points. Then I copy
> data from the input buffer into the table.
> It has to be running with the audio, since the audio is being re-mixed in real
> time.
> Everything works fine if I'm using the onboard sound - e.g. OSS, but the
> problems only happen when I switch to jack. Of course the onboard sound would be
> OK if I was using only output, but the whole point is to live-sample the input.
> The mic input on my laptop is really crappy.
>
>> - - try to get the DSP graph building into a separate thread.
>> well, this involves pd~ or the like....
> Dammit again - I'm using the second core of the machine for the live score,
> dynamic object creation in GEM
>   - but I see the new version of Inscore supports PD, so all my work over the
> last 6 months has been for nothing.
> Pah!
>
> Ed
>
>
> fgmasdr
> IOhannes
>
>
>
>
>
> [1] btw, it's usually really easy to check things: e.g. running your
> patch with "-nogui" and see whether you get dropouts might take about
> the same time as (you) asking on this list, (me) answering on this list
> and (you) reading the answer - not counting the delay due to
> amil-servers and the like. anyhow.
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