From: Tim E. R. <ter...@ro...> - 2012-06-15 23:57:28
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> On March 18, 2012 5:29:47 PM Tim E. Real wrote: > > http://www.piano-midi.de/midis/chopin/chpn_op66.mid > > Import this song into MusE and look at the tempo graph. > It's all over the place. > > I guess it's a NECESSITY for flowing classical music like this. > This kind of music is always changing tempo. > It's beautiful though. > > This means displaying the tempos on some time-line would be a mess > unless we could turn them off or limit them or something. > > Tim. Hi just a heads-up, in release_2_0 branch: In view of the above, I figured the only way to actually record such a piece is by operating a tempo lever or pedal while performing it, while a tempo metronome is ticking so you can try to align your playing with it (ahead of any quantizing later). The song above might have been fully programmed, but still... * Sync fix: MusE now records tempo changes from externally clocked midi. Still experimental but non-intrusive: You will be asked at the end of recording if you want to transfer the recorded tempos to the master tempo graph. Tested OK so far with ALSA and Jack midi. Best results ATM may be when recording from position zero, not 'continuing' a recording or skipping 'fwd' or 'rew'. TODO: Record Jack timebase changes! Find patch someone sent years ago, likely still useful... I'll try from scratch. Should be fairly easy. ------ Tech + user info: Be aware that external midi clock can be very jittery. In order to filter this, and limit the sheer number of tempo changes recorded, there is a 16-stage averaging filter for the clock events. At the default user setting of 384 division, one clock = 16 MusE ticks. There are 24 clocks per quarter note. Originally the filter was set to 24 stages but I lowered it to 16 stages for now, for a bit more responsiveness. That gives something a bit better than say, quarter-note tempo change resolution. I may make this user-adjustable but not too low - a huge flood of jittery changes can be recorded. As a further anti-jitter measure I quantize the tempos to a value of 2, that is 120, 122, 124, etc. I figured, at least for pure midi hounds, you'd rather choose stability and less tempo graph fluttering, over accuracy. It's very stable, once you leave that tempo lever alone! I am working on a 'lock' range and separate smaller filter for sudden large changes. If an obvious sudden large change occurs (such as a programmed drop from say 120 to 100) this will immediately restart the filter, for better response. But it's tricky, it has to be detected in fewer stages than the main filter, meaning more jitter. Code's there but disabled for now, fixing a bug with it. The reason I mention all of this is, and it may be obvious to some, try not to plan to record any /audio/ at the same time as synchronizing to external clock which changes tempo. The resulting MusE master tempo list may not cause the midi to line up exactly or drift with respect to the audio on playback. For those who must, it's one reason for adjustable clock filters (and snappier, more intelligent ones)... Otherwise for you midi hounds, imprecise recorded tempos don't matter, I hope this helps. (This could be part of documentation but it's not finished - todo Jack Timebase etc.) Tim. |