Re: [fluid-dev] MIDI bank select problems
On Thu, Nov 28, 2013 at 11:53 PM, Chris Robinson chris.k...@gmail.comwrote:
On 11/28/2013 08:05 PM, Element Green wrote:
Good idea to read through the archives.. I also did this and came up with
a thread which occurred around the date when the code was checked in for
the synth.midi-bank-select option. I came up with this email in
particular
from Pedro which describes the MMA mode:
https://lists.nongnu.org/archive/html/fluid-dev/2010-08/msg00046.html
Hmm, odd. According to that, Creative thinks MMA mode should be CC0*128 +
CC32, but neither the GM1 or GM2 standards define this behavior. In fact,
GM1 doesn't have bank select messages, and GM2 hadn't been adopted yet when
the SoundFont (1 or 2) stuff was created. Looks like this is just what
Creative thought the MMA was going to standardize on, but it's really an XG
mode that doesn't ignore CC0 as part of the bank number.
The original MIDI standard pretty much spells that out, though I think
there was some confusion around it leading to divergent vendor standards.
CC 32-63 are supposed to be the least significant bytes and CC 0-31 the
most significant bytes of 14 bit controller values.
Instead, the MMA went a different way with GM2. CC0 selects a channel type
(120 = percussion (only allowed on channels 9 and 10), and 121 = melodic),
and CC32 selects a bank (must be 0 on percussion channels).
I don't really see it as a different way in respect to MIDI, but more in
comparison to the other instrument mapping standards. Interpreting CC0 and
CC32 as MSB/LSB of a 14 bit number (as the GM2 article on Wikipedia also
says), then GM2 percussion is on bank 15360 and the melodic banks start
at 15488. While SoundFont files physically can store up to a 16 bit value
for bank numbers, the specification says it should be limited from 0-127
for melodic banks and 128 is for percussion. So it seems like if a GM2
mode were to be added to FluidSynth, the actual bank numbers would be set
to the usual SoundFont convention, rather than trying to conform SoundFont
files to the GM2 spec. So a GM2 SoundFont would contain melodic
instruments and variations on the various banks and percussion presets
would still be on bank 128, as usual. A gm2 mode could be added to
FluidSynth which would respond to a CC0 MSB bank value of 120, by assigning
percussion bank 128 and ignoring the LSB. Or in the case of CC0 MSB being
121, CC32 LSB would be used to select the bank number.
I'm personally curious though, why you chose GM2 as your
MIDI variation of choice?
Mainly because GS and XG are vendor-specific, while GM2 is about as
standard as you can get here. And unlike GM1, GM2 allows switching channel
9 to act like a normal channel, which I feel adds an important bit of
flexibility in letting the app developer worry about where and how
instruments can be mapped in a custom soundfont.
What becomes standard is what is wide spread and adopted, whether its
defined by a vendor or MMA. SoundFont for that matter is a vendor
specification. I haven't seen many GM2 SoundFont files around and I'm not
sure how many MIDI files there are out there, perhaps someone can elighten
me on this. I agree though, that having more flexibility in regards to
percussion channels is good. Currently the only MIDI mode which FluidSynth
supports which has that feature is XG mode (bank 120-127 selects
percussion, anything else is melodic).
In reading that above email, however, it seems Creative says SF2 synths
must use GS mode by default, and I'm aiming for OpenAL Soft's MIDI
extension to provide an SF2-compatible synth so developers can know what
they're working with. So I guess I shouldn't try forcing GM2 on
initialization.
Still, that leaves the question of how to allow apps to use the
bank/instrument they want on channel 9. I suppose the correct way would
be for them to send a GM2 On sysex message {0x7E, 0x09, 0x03}, as described
here http://www.midi.org/techspecs/midimessages.php, if they want it.
But I don't think FluidSynth recognizes that.
The other possibility is that I could watch for CC32 being set to 120 or
121 on channels 9 and 10 in OpenAL's MIDI event handler, switching the
channel to be percussion or melodic accordingly via
fluid_synth_set_channel_type, and leaving CC0 to be the bank number as per
GS mode (basically reversing the bytes as described in GM2).
Supporting the GM2 On sysex message sounds like the better option to me,
as its the more standards-compliant way. Watching CC32 is also a
possibility, but I'd like to avoid custom behavior if I can.
I had worked on some code which selected the MIDI mode based on SYSEX
messages, but I think it was abandoned at some point, can't remember why.
Perhaps it was the complication of other caveats in regards to MIDI modes
(not just bank selection). Seems like SYSEX mode selection would be a good
thing to have for other MIDI modes as well, though.
At any rate, I think such logic should
Re: [fluid-dev] MIDI bank select problems
That makes sense to me too. Element On Fri, Nov 29, 2013 at 6:15 PM, Chris Robinson chris.k...@gmail.comwrote: On 11/29/2013 11:31 AM, Element Green wrote: The original MIDI standard pretty much spells that out, though I think there was some confusion around it leading to divergent vendor standards. CC 32-63 are supposed to be the least significant bytes and CC 0-31 the most significant bytes of 14 bit controller values. Instead, the MMA went a different way with GM2. CC0 selects a channel type (120 = percussion (only allowed on channels 9 and 10), and 121 = melodic), and CC32 selects a bank (must be 0 on percussion channels). I don't really see it as a different way in respect to MIDI, but more in comparison to the other instrument mapping standards. Interpreting CC0 and CC32 as MSB/LSB of a 14 bit number (as the GM2 article on Wikipedia also says), then GM2 percussion is on bank 15360 and the melodic banks start at 15488. The way I see it, it's basically a shifted+masked value pair. i.e. int type = ctrl 7; int bank = ctrl 127; The upper bits hold the channel type, and the lower bits hold the bank number. You can't use more than 128 melodic banks (just like with GS and XG) since the 128th bank value will overflow into the type bits: 000100 /* CC0 121 */ 000100 /* bank 128 */ And since percussion must set CC32 to 0, you still get 128 melodic banks (0-127), and a percussion bank (implied 128). Though that's just my interpretation from the wikipedia page. ___ fluid-dev mailing list fluid-dev@nongnu.org https://lists.nongnu.org/mailman/listinfo/fluid-dev
Re: [fluid-dev] MIDI bank select problems
On 11/28/2013 10:51 AM, Element Green wrote: Did you see any information that indicated that mma mode was supposed to be GM2? When I read this old thread: https://lists.nongnu.org/archive/html/fluid-dev/2012-07/msg00024.html, it sounds implied. It lists GM, GS, XG, and GM2 as bank selection modes, but the modes available are 'gm', 'gs', 'xg', and 'mma'. And assuming MMA = MIDI Manufacturers Association, the group that creates/adopts the General MIDI specs, that leads me to think mma is supposed to be GM2. If that's not correct, then I apologize. What part of that Wikipedia article leads you to believe that channels 10 and 11 (9 and 10 as far as FluidSynth is concerned) can be switched to melodic with GM2? Under General requirements: Simultaneous Melodic Instruments – up to 16 (all Channels) Simultaneous Percussion Kits – up to 2 (Channel 10/11) That indicates that channels 10 and 11 (9 and 10) can be switched between melodic and percussion, to give up to 16 melodic channels (0 percussion) or up to 2 percussion channels (14 melodic), depending on your needs. ___ fluid-dev mailing list fluid-dev@nongnu.org https://lists.nongnu.org/mailman/listinfo/fluid-dev
Re: [fluid-dev] MIDI bank select problems
On Thu, Nov 28, 2013 at 8:32 PM, Chris Robinson chris.k...@gmail.comwrote: On 11/28/2013 10:51 AM, Element Green wrote: Did you see any information that indicated that mma mode was supposed to be GM2? When I read this old thread: https://lists.nongnu.org/ archive/html/fluid-dev/2012-07/msg00024.html, it sounds implied. It lists GM, GS, XG, and GM2 as bank selection modes, but the modes available are 'gm', 'gs', 'xg', and 'mma'. And assuming MMA = MIDI Manufacturers Association, the group that creates/adopts the General MIDI specs, that leads me to think mma is supposed to be GM2. If that's not correct, then I apologize. Good idea to read through the archives.. I also did this and came up with a thread which occurred around the date when the code was checked in for the synth.midi-bank-select option. I came up with this email in particular from Pedro which describes the MMA mode: https://lists.nongnu.org/archive/html/fluid-dev/2010-08/msg00046.html I was aware what MMA stood for, but I was not aware what it actually correlated with as far as its intended effect. Seems it reflects the ability to specify a 14 bit bank number using bank MSB/LSB messages according to that email. So its not GM2. I guess this means a gm2 option could be added. I'm personally curious though, why you chose GM2 as your MIDI variation of choice? What part of that Wikipedia article leads you to believe that channels 10 and 11 (9 and 10 as far as FluidSynth is concerned) can be switched to melodic with GM2? Under General requirements: Simultaneous Melodic Instruments – up to 16 (all Channels) Simultaneous Percussion Kits – up to 2 (Channel 10/11) That indicates that channels 10 and 11 (9 and 10) can be switched between melodic and percussion, to give up to 16 melodic channels (0 percussion) or up to 2 percussion channels (14 melodic), depending on your needs. Now that a re-read that, it does indeed sound like it confirms the ability to switch a percussion channel to be a melodic one. Cheers. Element Green ___ fluid-dev mailing list fluid-dev@nongnu.org https://lists.nongnu.org/mailman/listinfo/fluid-dev
