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Pitch Shifter and Speed Shifter for VS1005 / VSOS

Posted: Tue 2017-03-14 15:47
by Henrik

Here is a brand new driver, called FTOPITCH.DL3. It connects to stdout, and offers a combined pitch shifter / speed shifter.


Normally, if you increase the playback speed of an audio file, the song will play at a higher tempo, and also at a higher pitch. Equally, if you slow playback down, both tempo and pitch get lower.

In some applications (e.g. karaoke, or language learning machines), it is desirable to be able to change pitch and tempo separately.

A pitch shifter can change playback pitch without changing playback tempo.

A speed shifter can change playback tempo without changing playback pitch.


FTOPITCH.DL3 offers both functions. It has been optimized to give best quality when the audio sample rate is between 32 and 48 kHz. Se the accompanying README.TXT file to see how to change pitch / speed from the C code or from the command line.


A new version or PlayDir is included, which shows how to program the shifter. It has 6 new keys:
  • '+' - Increase pitch by 0.5%.
  • '-' - Decrease pitch by 0.5%.
  • '=' - Reset pitch.
  • 'f' - Make playback Faster by 0.5%.
  • 's' - Make playback Slower by 0.5%.
  • 'b' - Go back to Base speed.
Kind regards,
- Henrik

Re: Pitch Shifter and Speed Shifter for VS1005 / VSOS

Posted: Tue 2017-05-23 14:47
by Henrik
The Pitch shifter / Speed shifter as well as the newest PlayDir programs are now an integral part of the VSOS 3.42 Root and Libraries Source Code package, available at the end of this thread:

Kind regards,
- Henrik