On Tuesday 20 Jun 2006 21:04, Pedro Lopez-Cabanillas wrote: > On Monday, 19 June 2006 18:32, Chris Cannam wrote: > > Note that none of this is an issue when importing MIDI files, because > > each distinct program gets separated out to a distinct track > > This isn't the current behavior of the MIDI import function, and I don't > remember it was as you say in the past.
No, you're right. I was thinking of tracks that have channel events sent to more than one channel, which we split out into more than one track in order to assign each to a different instrument. > On the other hand, I find some features related to Instruments very poor or > even wrong. For instance: why the MIDI channel is an attribute of the > Instrument? why the Instruments are attributes of the tracks instead of the > segments? And as a consequence: there shouldn't be a limitation of 16 > instruments per device. 16 instruments per device is an arbitrary number that just coincidentally happens to be the same as the number of MIDI channels. If you change the 16 at AlsaDriver.cpp line 1005 to something else, you'll get a different number. It works just as well with 24 or 32, or 200 -- try it! But I fear and mistrust the instrument/device handling code, and particularly the logic that creates the instruments in the first place and tries to keep them in sync between GUI and sequencer. For example, look at what the .rg file loader (rosexmlhandler.cpp:1868 and thereabouts) does when reading the instrument elements within each device element. It looks up the instrument according to its ID, which is a global numbering from 2000 upwards for MIDI instruments, and applies the given bank and program to that instrument if it exists, dropping them entirely if it doesn't. The significant points are (a) this code never actually creates instruments or assigns instrument IDs to devices -- that's done when the devices are created, which is originated by the sequencer if the devices are created to match existing available MIDI connections -- and (b) the instrument ID is not local to the device, but global. Put together, this means this code has no way of dealing with (or really knowing about) the situation where an instrument ID is found on the wrong device. For example, if you save a file with 16 instruments per device (so that instrument IDs 2000-2015 are on device 0, 2016-2031 on device 1 etc), then increase the number of auto-generated instruments per device to 24 and reload the file, the instruments 2016-2023 will have moved from device 1 to device 0 and tracks set to those instruments will suddenly play through a different MIDI port. The root cause of this is that instruments are being created in the wrong place -- they're created on the whim of the sequencer, and then propagated back to the GUI. This happens because we want to make sure there are candidate instruments with likely connections available for the MIDI ports that the sequencer finds on startup. As a result the code that really should have the ultimate control over the device and instrument setup (the code that reads in the saved devices and instruments from the .rg file) doesn't have any real control at all, because the instruments are already there. It can ask for the sequencer to create a new device, but it's still at the mercy of the sequencer's built-in count of instruments for that device. In fact, all the instruments and devices should be created at the GUI, or at least the GUI should have control over when and what is created -- only the available connections should be managed on the sequencer side. > My proposal is to associate Instruments to segments instead of tracks, and > dissociate the MIDI channels from instruments moving them to the track > level. I'm not sure that this latter bit is necessary, if there can in fact be more or less than 16 instruments per device -- is it? Would it make much difference either way? Associating instruments with segments seems at first glance like an excellent idea. I wonder if there are any big disadvantages? It sounds equally useful for audio instruments, to allow you to apply different effects plugins to different segments on the same track. Chris _______________________________________________ Rosegarden-devel mailing list Rosegarden-devel@lists.sourceforge.net - use the link below to unsubscribe https://lists.sourceforge.net/lists/listinfo/rosegarden-devel
