--- On Mon, 7/9/12, David Henningsson <address@hidden> wrote:
From: David Henningsson <address@hidden>
Subject: Soundfont banks (was: Re: [fluid-dev] OSC support)
To: "FluidSynth mailing list" <address@hidden>
Cc: "jimmy" <address@hidden>
Date: Monday, July 9, 2012, 6:55 AM
On 07/09/2012 03:07 PM, jimmy wrote:
"SoundBlaster soundfont specs
only allow 128 banks of 128 instruments" --
That's what I get from Pedro and David.
When ask about MIDI specs support for MSB (128
selections) and LSB (128 selections) for sound banks, they
didn't have an answer.
As for following specs or not, I'm pragmatic about it. I'd
like to follow the specs whenever possible, but if something
else proves useful to a lot of people, and does not break it
for other people, I'm okay with merging such patches.
As for soundfonts, I remember having discussions on how to
best map CC0 and CC32 to the SoundFont's wBank value in
different GM/GS/XG/GM2 modes, which was not trivial to
answer. Therefore we have the "synth.midi-bank-select"
option that uses different mappings depending the mode you
select. Isn't that option working for you?
My patch specifically allows XG-soundbankd and XG-drumbank selections, and only
in XG-mode. XG-drumbanks can be at various MSB bank values of 120, 126, 127...
in combination with various LSB bank values for different XG hardwares.
Again, my patch only affects XG-mode. It allows Drumbanks to be used by any
channel, not just channel 9 (10 with 1-starting-index). It also allows
multiple drum channels at the same time, with is used by various XG hardwares
and XG-MIDI files.
Sadly, my patch never made it to the SVN code base, so the XG-mode soundbank
selection and drumbank selection never worked in the official FluidSynth code
base.
As for the soundfont spec, it both says:
"MIDI CC0 Bank Select - When received, the following program
change should select the MIDI program
in this bank value instead of the default bank of 0
MIDI CC32 Bank Select LSB - When received, may behave in
conjunction with CC0 Bank Select to provide a total of 16384
possible MIDI banks of programs."
It means, by default, the value of CC0 and CC32 is assumed to be 0 (zero). Let
me use 0-starting-index number here. Some instruments use 1 ss starting index,
so adjust those numbers accordingly.
Some earlier hardwares only use MSB, only send MSB (CC0), never send LSB (CC32). That's
what ["MIDI CC32 Bank Select LSB - When received,"] tries to clarify.
CC0 and CC32 each has 7-bits (0-127 in decimal values). So each is capable ot
128 values, putting them side-by-side, that's a 14-bit binary number that is
0-16383, or 16384 distinct numbers.
Some vendors (including, but not just Roland and Yamaha) went about
implementing it for their MIDI hardwares. It should not really matter if they
follow the 14-bit numbering for calculating any of 16384 distinct banks. I
look at it as MSB (Most Significant Bits) means higher-order bits like the
hundreds or thousands, and LSB (Least Significant Bits) means the first few
numbers when we start counting.
Although, some people took short-cut, especially in Softwares, emulating Roland
GS soundbank selection. For example, some earlier Roland GS hardware and
software modules only use MSB (CC0), and assume LSB (CC32) to be 0. In other
words, they simply ignored LSB (CC32) in those hardware and software GS-mode
modules. So, some third-party hardware and software emulation of GS-mode
simply use 7-bits of MSB for the soundbanks switching, completely ignore the
LSB (CC32). If those third-party folks had use the 14-bit number from the
beginning, simply zero-ing out the LSB (CC3) for bank selection, it would be
simple to move forward.
Here's a description of how Roland GS hardwares do (changes with successive
hardware releases):
https://en.wikipedia.org/wiki/Roland_GS
Typically, cc#32 (Bank Select LSB) was used to select a family (i.e. 1 -
SC-55, 100 - MT-32 etc.) then cc#0 (Bank Select MSB) was used to set a
particular variation bank.
In other words, it should have been the other way around. But, they use LSB
for the different hardwares ID. Each hardware uses MSB for the maximum of 128
soundbanks of 128 instruments per bank. That's the [128 banks] x [128
instruments] limit per family of hardware, designated by the Hardware ID used
by LSB (CC32).
In other words, GS-mode hardwares only use 128 banks of 128 instruments for any
particular "hardware family". That's a limitation of using only MSB (7-bit
number) for limiting bank selection.
Yamaha XG hardwares, on the other hand use the more logical ordering of bits in
the 14-bits numbers. They use combination of MSB and LSB to signify specific
banks, including drum banks. Which allows for addressing fuller range of
[16384 banks] x [128 instruments]. Of course, some numbers may have already
been used by older hardware, and for backward compatibilities, some of those
numbers may be avoided for the time being. But still, much more number of
banks can be used in XG-mode.
Not only that, MIDI-2 instruments of more recent years, all use the combination
of MSB and LSB for bank selection.
and also says:
"The special case of a General MIDI percussion bank is
handled conventionally by a wBank value of 128. If the value
in either [wBank or wPreset] field is not a valid MIDI value
of zero through 127, or 128 for wBank, the preset cannot be
played but should be maintained."
Kind of confusing in itself, IMO.