[mkl]

I think you're misunderstanding. The slow-motion screen recording video can be sped up to match separate non-realtime software synthesis of audio (using e.g. Timidity++). It can all be entirely software so there aren't physical limits to worry about.

[Rochus]

Try to do that with a factor of e.g. 10 (you would likely need a factor of 1000 to cope with a "composition" of millions of notes) and observe the quality. The "physical limits" (e.g. Nyquist rate) also apply to the calculations done by a computer. To cope with the speed-up of slow motion to real-time you'd have to re-sample or transpose. Even with a very large sampling rate both of these transformations only produce useful results within narrow limits (less than an octave, i.e. factor two).

[mkl]

The quality will be essentially perfect. The wave file is rendered in software, as slowly as it needs to go. The rendering speed has nothing to do with playback speed, sampling rate, or frequency. Think of it like a ray tracer generating a few pixels a second and gradually building up the frames of a movie. You could generate one audio sample per second and save them to a file, and twelve hours or so later you'd have a 1-second long piece of 44.1kHz audio. There is no speeding up or resampling or transposition involved because the audio file was generated with the right sample rate (nothing to do with the generation/calculation rate).

[Rochus]

I responded to the fellow stating "The article says they sometimes play them slowly and speed the recording up to the correct speed afterwards." which implies a change to the time scale. But also if you do a "perfect" non-realtime offline rendering Black MIDI is pointless; a piano has 88 keys; if you want to play thousands of notes a second then the only "benefit" you get is either a comb filter effect when the same note is triggered nearly the same time or a 3 dB gain (on maximum) if triggered exactly at the same time; there are easier ways to achieve this, even in real-time.

[TheOtherHobbes]

The benefit is you can create sample-accurate arpeggios, amplitude-modulated timbres, and other extreme and unplayable effects famously (over)used in tracker music.

You don't seem to have experience of what trackers can do. Essentially Black MIDI is rendered tracker music with a nice animated piano roll background.

On a slow system a render will take longer than real time. On a fast system it won't.

[Rochus]

> You don't seem to have experience of what trackers can do.

Well, I'm a trained musician and use sequencers since Atari times; a tracker seems to be just a sequencer more geared towards people who prefer to enter numbers instead of playing; if so I would prefer something like csound or chuck; but I was more interested in live music the last few years; here is what I currently do: http://rochus-keller.ch/?p=1153

[mhb]

Thanks. Why one white shoe?

[oynqr]

Is there any software which actually does this properly? I've tried timidity, but it doesn't produce decently sounding output with the black midis I have.