playback: improve musical timekeeping: start playing samples just early enough to align score "note start" with actual musical onset moment in sample

As far as I can tell, currently samples start playing from the beginning (attack phase) at the moment the note starts in the score.

However, this means every sample (except ones with zero attack) is musically late, as it will merely commence the attack phase on time, instead of arriving at the musically meaningful onset on time.

Furthermore, every instrument (in fact potentially every sample within every instrument) will probably have different attack lengths/times, with correspondingly varying resulting drag (further perturbed by the resampling required by note pitch).

It seems to me this approach would result in a sample-based playback that is inherently very bad at musical timekeeping across the orchestra.

Is this the case with MuseScore? If yes, I propose we improve it.

This would require obtaining the musical onset point of the sample. Ultimately that should come from the soundfont itself (extending the file format if needed), but as a transitional/compatibility measure it might be very well worth to develop some automatic sample analysis as a fallback to provide an instant improvement to users to build momentum.