[PD] How to navigate a long sound file in vanilla PD

peiman khosravi peimankhosravi at gmail.com
Tue Mar 31 11:51:31 CEST 2015

Sorry, forgot to reply to all.


I had this problem in maxMSP recently and found a working solution. Note
that I was only on a laptop so I don't know how relevant this is to your
question. Below is the solution I found on the Max forum (I don't have the
link right now but it should come up on google).

1- Read the file [silently] from disk (using sfplay~ or equivalent), at 50
times the original speed and record the output into a buffer that is 50
times smaller than the original file.

2- You can navigate through this smaller buffer and multiply the output by
50 to get the correct time pointer into the original file. I then read the
original file from the disk, instead of loading it into a buffer.

3- Since I'm making my patch for concert playback, I have put in place a
checking mechanism that looks for an existing 'waveform' file. (The patch
automatically names these originalFileName.wave.aif.) If it exists, the
waveform file is read into the buffer, otherwise, the loaded soundfile is

I can send you my patch if you are interested. I don't see any reason why
this can't be implemented in PD. Although the graphical scrolling might be
slower in PD. I'd be interested to know if this works in PD.


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On 31 March 2015 at 10:18, Stefan Tiedje <stefantiedje at googlemail.com>

> Hello list,
> might well be the first post here, though I am well experienced in
> Max/MSP...
> As there is no way to get Max patches run on mobile devices, I want to do
> it in PD using the MobMuPlat apps for Android/iOS.
> The task would be to simply to play a stereo sound file, but of about one
> hour lebgth. As MobMuPlat only supports vanilla PD I am restricted to that
> as far as I know.
> In the docs and on the net I did not find any way to navigate within that
> playback. (Its crucial for rehearsals.) The size is too big for loading it
> into RAM (the mobile devices which are around often have less than 1 GB of
> RAM), Is there a known way to tackle this seemingly simple task???
> A tedious way, I want to avoid, would be to split the sound file into
> pieces, which would at least let me jump in at specified places, but that
> would eat up the space on the device, as each piece would have to play
> until the end...
> Of course I would also love to find a way to play back an mp3 and freely
> navigate within that as well...
> Any hints how to proceed are appriciated...
> Stefan Tiedje
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