[PD] 64 bit audio?

katja katjavetter at gmail.com
Fri Nov 27 12:59:34 CET 2015


This topic keeps popping up on Pd list with stable frequency. Here's a
text about the effects of double precision in Pd:

http://www.katjaas.nl/doubleprecision/doubleprecision.html

It illustrates that double precision as Pd's basic data type will
improve results for very specific cases (like reading long buffers,
subsonic filtering), but it comes at a price to be payed by everyone
all of the time. In terms of performance penalty, the price seemed to
be acceptable at the time of writing (2011). That was before the
advent of pico computers like Raspberry Pi, for which the price of
doubles is much higher. Also I realized only later that making _all_
external libs double-precision-aware is mission impossible.

Since you can't mix single precision Pd with double precision
externals or vice versa, you can imagine what a hairy expedition it
is. As I see it now, a double precision build is mainly valuable for
evaluation. It helps finding out how important precision is for some
routine, and may even provide insights which help to fix some
precision issue within the constraints of single precision Pd. Here's
a video where you can see double precision Pd in action (in the latter
part):

https://www.youtube.com/watch?v=93632nc8LVs

Katja

On Fri, Nov 27, 2015 at 5:09 AM, Alexandre Torres Porres
<porres at gmail.com> wrote:
> not much attention here, but here's an anser from the SC list about their
> discussion in porting the audio server to 64 bits
>
> "The biggest advantage of higher resolution is in things like filter loops,
> but most SC UGens already do 64 bit calculations internally where that’s
> appropriate"
>
> I guess it makes sense, 32 bit is more than enough for dealing with audio
> signals/amplitudes.
>
> So I assume Pd won't likely bother to become 64 bits like Max did for
> similar reasons, and maybe just think "internal 64 bit calculations" sooner
> or later, or does that already happen?
>
> cheers
>
>
>
> 2015-11-25 4:26 GMT-02:00 Alexandre Torres Porres <porres at gmail.com>:
>>
>> This may already have been discussed on the list I guess, but I wonder if
>> there's any plan to have Pd running audio (and control) signals at 64 bit
>> audio in the near coming future.
>>
>> I know there's a version you can compile with double precision for a while
>> now, and I'm just wondering if we should naturally expect that this will
>> eventually happen as a default, because that is the natural course to go, or
>> "not at all"...
>>
>> One way or another, I was hoping for some explanation why it would likely
>> and naturally go towards a 64 bit resolution or not (technical issues / pros
>> & cons).
>>
>> thanks
>>
>>
>
>
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