How does FS interpret SoundFont Preset generators, specifically the VolEnv and ModEnv?
In the SoundFont spec, it seems - and at times explicitly states - that the Preset values are ADDED to the Instrument Values, and are interpreted as Units specified in the spec. From page 45 (2.01 sepc): "Generators at the Preset Level are instead considered relative and additive to all the default or instrument level generators within the Preset Zone. For example, a value of 2400 timecents for the attackVolEnv generator in a preset zone containing an instrument with two zones, one with the default attackVolEnv and one with an absolute attackVolEnv generator value of 1200 timecents would cause the default zone to actually have a value of -9600 timecents or 4 msec, and the other to have a value of 3600 timecents or 8 seconds attack time." However, in both the Vienna and Viena editors, it doesn't work that way. Instead, for example, a attackVolEnv in the Preset (PGEN) serves as a MULTIPLIER and does not represent the Unit (in this case TimeCents). As an example, there is a SoundFont called CHORIUM and when opened in Viena, you see the Preset's Global Zone has a value of 30 in attackVolEnv, and the Instrument zones mostly don't have a value listed, so you get 30ms as the audible value, since 30 x 1ms (the default value) = 30ms. I looked inside the Chorium file and sure enough, the value is 0x1739, decimal 5945, and when processed through the TimeCents formula, comes out to 30.999 (that is, 31). In Viena (which is NOT the spec but it should follow the spec) the listing doesn't say "sec" but "X", and certainly in the above example the attack time is NOT 31sec when I play it back. So for some reason Viena (and Vienna) interprets the Preset values as MULTIPLIERS and aren't even in the Units the spec defines, which is TimeCents (absolute time values). So, my questions are - how does FS do it, why does it do it (in view of the spec violation), and also why is this so against the spec? Is the spec "wrong"? How can a spec be "wrong"? Garth Hjelte Sampler User
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