[FFmpeg-devel] Mentoring project: music test source

Nicolas George george at nsup.org
Sun Sep 30 20:41:03 EEST 2018


For the next rounds of sponsored internships, I would like to propose
the following project, that I would mentor:

A music-like audio lavfi source for testing purposes.

That means a deterministic pseudo-random stream of notes with varied
frequencies, with a structure that looks like music and would trigger
the same pathways in filters and codecs.

It would be based on asrc_sine, which already has a fast bit-exact
sinusoidal signal generator. On top of that, the filter would change the
frequency randomly to make notes according to a tempo, preferably by
following harmony rules, and would shape the note with an envelope and

As qualification tasks, I can propose:

- make a "musicalscale" filter source that outputs the audible spectrum
  of notes in sequence;

- make a filter source that sounds like a percussion instrument hit
  repeatedly at a regular interval.

What do you think of it, in terms of usefulness and difficulty?


  Nicolas George
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