SF2 / MIDI-Player for Audio Library or simple Stretching of WAV-Files ?

[Erich]

Hi all,
I had played around with the ESP32 last year and had found this library from Earle Philhower III and used it as a Sample-Player in my project.
https://github.com/earlephilhower/ESP8266Audio
I moved only a bit of the code from ESP8266 to my ESP32 and was surprised to get it working.
In my project, I used the wavplayer to play and loop a WAV-File from Progmem in variable speed.

Weeks ago I bought my first Teensy and thought that the Audio-Library is able to play WAV-Files in variable speed .. but it cannot.

A workaround could be to modify the player for Soundfonts which is existing in the Audio-Library.
It seems to be a bit of work to transform an SF2 into the right format.

Earle Philhower was able to use the SF2-File directly which works well on the ESP8266.
Could this library, which he optimized for the ESP8266 work with the teensy 3.x too??
https://github.com/earlephilhower/ES...btinysoundfont
Earle hat also created a MIDI-File-Player together with the SF2-Library. ... could be interesting to play back stored (short or longer) MIDI-Tracks.

Who is able to transform this for the Teensy?

As an Alternative, I had created my library for the ESP32 to stretch or compress an existing WAV-File by repeating Samples or dropping Samples
... the code does not support the expected Filter or Reverb! ... only the Pitch works acceptable for Rythem- or Percussion-Loops.
https://github.com/ErichHeinemann/hm...eratorSAMPLE.h
https://github.com/ErichHeinemann/hm...atorSAMPLE.cpp

What would be the best option to get cool pitchable Samples in the Audio-Library for the Teensy? Direct SF2-Play or Simple Stretching like I did on the ESP32?

Regards
Erich

[wcalvert]

AudioEffectGranular can pitch shift and change playback speed. Just route an AudioPlaySdWav (or whatever sound source) through it.

Take a look here for the example: https://github.com/PaulStoffregen/Au...r/Granular.ino

[Erich]

Hi all, after some days I am able to change the speed of a played WAV-File.
1. I replaced the files play_sd_wav.h and play_sd_wav.cpp .. still 16bit and the current version is only able to stretch 44.1kHz 16Bit-Stereo-Files. Mono-Files and other sampling-times are on the ToDo-List.

If someone wants to peek inside the current solution:
https://github.com/ErichHeinemann/teensystuff/

The quality is ok for Drum-loops and I have tested with Sinus Loops too to find bugs in the solution.
If You test it, keep in mind that it has to be copied into the existing Audio-Library.

I have copied mine over from the original place (Mac OSX)
/Applications/Arduino.app/Contents/Java/hardware/teensy/avr/libraries/Audio
too
Users/myUserName/Documents/Arduino/libraries/Audio

cd /Applications/Arduino.app/Contents/Java/hardware/teensy/avr/libraries/Audio
cp -R * /Users/myUserName/Documents/Arduino/libraries/Audio

and then I have replaced the 2 files under Arduini/libraries/Audio/ and created some test files and tested with the new example.

With this solution, - no extra additional library AudioEffectGranular is needed to store the Grains of the WAV-File.

[wcalvert]

I'm guessing you're taking this route rather than the Granular effect because of RAM limitations?