[PD] meaning of delay(msec) and use callbacks in audio settings

[Alexandre Torres Porres]

>  I've seen really good setups get down to below 10ms (as low as 4)

what kind of setup? :) it'd be cool if we described some rigs here

cheers

2015-02-18 0:26 GMT-02:00 David Medine <dmedine at ucsd.edu>:

>  Basically these things have to do with performance.
>
> 'Use callbacks' has to do with how Pd communicates with your soundcard.
> There are two options, using callbacks, and blocking. In the callbacks
> scenario, your computer processes samples then asks the sound card to 'call
> you back' when it's ready to receive those samples (i.e. when it is out of
> audio to play and needs some more). In the meantime, you can process more
> samples, or check out what's going on on CNN.com or whatever.
>
> In the blocking method the computer hands the samples to the soundcard by
> calling a function and if the sound card is not ready, it 'blocks' meaning
> it stops your function in its tracks until it is ready to receive the data.
> Your thread (Pd) will halt until the function that sends the audio has
> finished.
>
> Anybody out there, please correct me if I am spreading misinformation
> here, but this is my understanding of this distinction.
>
> Delay(msec) is a delay between logical time (when your computer computes
> the audio) and real time (when the sound comes out the speaker). You want
> to have some head room here. I've seen really good setups get down to below
> 10ms (as low as 4) without any glitches, but usually you want much more
> time ~50ms or so.
>
>
> On 2/17/2015 5:42 PM, Jonghyun Kim wrote:
>
> Fyi, I use jack on Linux for PD.
> On Feb 18, 2015 8:16 AM, "Jonghyun Kim" <agitato816 at gmail.com> wrote:
>
>> Hi list,
>>
>>  I would like to know about some features in audio settings.
>>
>>  I don't understand what mean these options.
>>
>>  *Delay(msec)* and *Use callbacks*
>>
>>  I googled these options, but still I don't understand. Is there some
>> document about it?
>>
>>  Thanks in advance,
>> akntk
>>
>
>
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