Hi, people. This is a bit loosely related to the Music project. Last week, someone unexpectedly gave me two MIDI synthetisers, a keyboard controller, amplifiers, and cabling. A nice gift indeed for me who would not afford such expenses :-). Playing with all this material, stealing bits of time in between more serious projects, I found out that if, on this Linux system, I write to `/dev/midi00', the bytes are made available in real-time to the synthetisers. So, if I only had a program able to dispatch bits of a MIDI file to `/dev/midi00' at the proper time, I could hear MIDI files with lower CPU overhead than with `timidity'. So, I wrote a small program doing that for MIDI file formats 0 and 1. Multi-processing is apparently not fully favourable to a MIDI sequencer, and I understood that if I want some precision, I should work for it. One avenue would have been to use special provisions for real-time in the Linux scheduler, but it would also require installing the sequencer program as `root' and some other fancy things, while I prefer simplicity. Instead, I tried to evaluate lags and latencies on the fly, and correct them appropriately. The result is satisfying enough. When the system gets loaded, music rendering could sometimes be slightly jerky, but overall, the beat stays precise. I also avoided floating-point computations or anything else that could yield accumulated rounding errors, and implemented regular quantum warping of the time reference (:-), so to decrease the overflow risk, while computing proper waits for very long delta times (like those who could exist on the timing track of some lengthy musical pieces). I'm not especially trying to make a "package" with the result, as it is only a toy and a study tool. There are also other free sequencers, which I did not evaluate (I should most probably have done that first!) and which are surely better in various ways. Nevertheless, in the GPL spirit, I'm willing to share this quick hack with anybody interested into using or growing it into free tools. I might also work on it too, who knows! :-) -- François Pinard mailto:[EMAIL PROTECTED] Join the free Translation Project! http://www.iro.umontreal.ca/~pinard
