[PD] Interruption of audio / Loading sound into array

Roman Haefeli reduzent at gmail.com
Fri Nov 4 11:50:38 CET 2011

On Fri, 2011-11-04 at 11:26 +0100, katja wrote:
> By coincidence I noticed an svn commit access request from Damian
> Stewart, back in 2008, where he proposes to 'implement multithreaded
> [soundfiler] read'
> (http://lists.puredata.info/pipermail/pd-dev/2008-12/012447.html).
> What has become of this? Is there any code from this project?
> [readsf~] and writesf~] are threaded, they operate in a child process.
> I guess it could not be otherwise? Because they do not intend to read
> all samples at once. Looking at the code in d_soundfile.c, I can
> understand why the whole of Pd should not be multithreaded. It is a
> lot of overhead. But [soundfiler~] read is another exceptional case
> indeed, it needs carefully scheduled loading if it is not to cause
> buffer underruns elsewhere. Such loading in portions would also mean
> the whole audiofile is not immediately available in memory. Therefore,
> the result would somehow be equivalent to the
> '[readsf~]-in-an-upsampled-patch'  trick.

The problem with the '[readsf~]-in-an-upsampled-patch' approach is that
you cannot know how fast you can do it without interrupting audio. Also
you cannot really fine-tune it since you can only set it to a speed to
any power of two. 
Ideally, a threaded [soundfiler] would load the file as fas as possible
in the background without interfering with Pd's main process and then it
would output a bang when done.


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