It's supposed to be possible with tabread4~, by using the onset inlet.
There's an example in one of the help files. I looked at it a year ago and
it was incomprehensible. YMMV.

If you figure it out, please post a simple example patch. This is my
greatest joy-killer in Pd, because I really want to work with audio files
which may be 1-2 hrs long.

On Friday, April 21, 2017, Antoine Villeret <antoine.villeret@gmail.com>
wrote:

> Hi,
>
> I'm looking for the best practice to scratch (change playback speed
> quickly) large sound file.
>
> I've already tried :
> - table and tabread4~ but table length is too limited
> - readsf~ : can't change playback speed easily (I didn't try resampling
> with block~ yet)
> - august/readanysf~ : seems pretty great but can't play backward, it also
> has a great feature : the return
> - moonlib/sfread2~ : works with both positive and negative speed but only
> with 16bit audio file and quite buggy (strange output when it can't find
> file)
> - moonlib/readsfv~ : works only with positive speed
>
> Does someone know how to play large sound file with playback speed control
> (positive and negative) ?
>
> Thanks
>
> Antoine
> --
> do it yourself
> http://antoine.villeret.free.fr
>