producing frequency notes

[Timothée Giet]

Le 31/07/2018 à 15:37, Emmanuel Charruau a écrit :
> Hi,
>
> I found this example
> https://github.com/jordan9001/SpectrumDraw
>
> Which produces notes from frequency which would have allowed to play 
> sounds without storing huge wav files and from the needed length. The 
> result is not nice to hear :(
>
> We need to find an other solution :(
>
> Emmanuel

Hi,

To answer your questions from irc,

I think in the old gtk version, each sample correspond to the longest 
note that can be played for each note.

And then the program stops playback earlier for shorter notes.

About the question regarding ogg/wav, I guess the sources are in wav and 
were converted to ogg/mp3/aac depending on the platform for package 
creation.

And again, note that for us ogg is not an option because only wav files 
are supported by the qml element used there, and the other one 
supporting compressed formats is completely not "realtime" enough to be 
used here.

I agree best solution would be to have a light soft synth playing the 
notes, but that requires some coding to create a clean synth with good 
sound in C++ and to integrate with qml after.

Other possibility would be to use a library like fluidsynth to play 
soundfont (which is a sort of file format embedding wav files, which are 
defined for some notes and other notes can reuse those and stretch a 
little to adapt the tone.. standard "instrument sample collection" file 
format), but this can be more complicated to make cross-platform.

Timothée