2010-08-03 22:48, Pedro Lopez-Cabanillas skrev: > [Sorry, this is a bit long...]
I'm glad you took the time to sort it out! > MIDI Bank Select messages are Control Change #0 (MSB) and CC#32 (LSB) [4]. Up > to FS-1.0.9, the behavior was that when a CC#0 message was received, the > value was used as the channel bank number. If a CC#32 was received later, the > bank number was recalculated as MSB*128+LSB and the result used as the new > channel bank number. The bank number is not immediately used, but reserved > until a Program Change message is received, and then applied to select a > sound preset from the loaded soundfonts. I remember finding that inconsistent, i e it mattered in which order MSB and LSB were received. I think that was one of the reasons for changing it. > Current behavior in the SVN codebase is that the soundfont bank number is > always calculated from MIDI Bank Select messages with the formula = > MSB*128+LSB, no matter if only the MSB or LSB values are received, > initializing the bank number to 0 for melodic channels and 128 for the > percussion channel. This new behavior has a problem when a MIDI song for GS > synths is played with a GS soundfont in FluidSynth: the selection of preset > sounds may be wrong. > > SF2 (SoundFont) files (like GeneralUser, FluidR3,...) have bank numbers < 127 > for melodic sounds and 128 for Drum kits, as recommended by the SoundFont > specification [5]. It is necessary to map the MIDI Bank Select numbers to the > SF2 bank numbers, because they won't always match. The sf2 spec says > that "The special case of a General MIDI percussion bank is handled > conventionally by a wBank value of 128. If the value in either field is not a > valid MIDI value of zero through 127, or 128 for wBank, the preset cannot be > played but should be maintained." > > Note that DLS soundfonts are different: they have 14bit bank numbers. But > FluidSynth doesn't use DLS files yet! > > There is not an universal behavior for MIDI Bank Select messages, because it > depends on several standards: GM, GS, and XG: > > GM (General MIDI) does not define Bank Select messages. The > document "gmguide2.pdf" [1] says that Bank Select (CC#0/32) should be > completely ignored in GM mode. > > GS (Roland) uses CC#0 as variation number, and CC#32 as a device emulation > number. Usually, LSB=0 for the main device mapping, and other numbers for > selection of families, or emulated devices [2]. > > XG (Yamaha) uses CC#32 as the bank number, and CC#0 as a melodic/sfx/drums > switch. The XG specification [3] says: > Bank Select MSB/LSB: 00H/20H > Cntrl# Parameter Data Range > 0 Bank Select MSB 0:Normal, 64:SFX voice, 126:SFX kit, 127:Drum > 32 Bank Select LSB 0 to 127. Default: 00 00H > If multipart parameter “Rcv BANK SELECT” is OFF, the part ignores this > message. The new bank selection does not become effective until receipt of > the next Program Change message. The Bank Select MSB selects melody voice, > SFX voice, or rhythm kit. The MSB allows any channel to be designated for > rhythm play. Bank Select MSB values are as follows. > 00H: Melody voice > 01H to 3FH: not used > 40H: SFX voice > 41H to 7DH: not used > 7EH: SFX kit (SFX voices arranged over keyboard) > 7FH: Rhythm kit (Rhythm voices arranged over keyboard) > > So there is no way to strictly follow all the standards at once. But at the > same time, the MIDI goal is compatibility, and the same should be the goal > for FluidSynth. The current behavior of bank# = MSB*128+LSB may be called > a "Strict mode" that works obnly when songs and soundfonts are specially > created with the correct numbers, and we can define a "Compatibility mode" > with the following rules, if we don't know which standard to follow: > 1. If MSB is received alone, or with LSB=0, then use MSB as the soundfont > bank > number. This is probably going to work with most GS songs. > 2. If LSB is received alone, or with MSB=0, then use LSB as the soundfont > bank > number. This is probably going to work with most XG songs. > In any other case, we need to know if the song/player follows the GM, GS or > XG > standards, either when a SYX message is received, or with a setting. > > The proposal is that this "Compatibility mode" should be the default. So, how about: banknum = LSB == 0 ? MSB : MSB*128 + LSB ? ...regardless of order received? That way, 1. and 2. work as you suggest, and "any other case" works as before - I believe, both as 1.1.0 and 1.0.9 worked, right? At least until we've got the Sysex/setting stuff for GM/GS/XG. // David _______________________________________________ fluid-dev mailing list fluid-dev@nongnu.org http://lists.nongnu.org/mailman/listinfo/fluid-dev
