sfplay3m — Plays a SoundFont2 (SF2) sample preset, generating a mono sound with cubic interpolation.


Plays a SoundFont2 (SF2) sample preset, generating a mono sound with cubic interpolation. These opcodes allow management the sample-structure of SF2 files. In order to understand the usage of these opcodes, the user must have some knowledge of the SF2 format, so a brief description of this format can be found in the SoundFont2 File Format section.


ares sfplay3m ivel, inotenum, xamp, xfreq, ipreindex [, iflag] [, ioffset] [, ienv]


ivel -- velocity value

inotenum -- MIDI note number value

ipreindex -- preset index

iflag (optional) -- flag regarding the behavior of xfreq and inotenum

ioffset (optional) -- start playing at offset, in samples.

ienv (optional) -- enables and determines amplitude envelope. 0 = no envelope, 1 = linear attack and decay, 2 = linear attack, exponential decay (see below). Default = 0.


xamp -- amplitude correction factor

xfreq -- frequency value or frequency multiplier, depending by iflag. When iflag = 0, xfreq is a multiplier of a the default frequency, assigned by SF2 preset to the inotenum value. When iflag = 1, xfreq is the absolute frequency of the output sound, in Hz. Default is 0.

When iflag = 0, inotenum sets the frequency of the output according to the MIDI note number used, and xfreq is used as a multiplier. When iflag = 1, the frequency of the output, is set directly by xfreq. This allows the user to use any kind of micro-tuning based scales. However, this method is designed to work correctly only with presets tuned to the default equal temperament. Attempts to use this method with a preset already having non-standard tunings, or with drum-kit-based presets, could give unexpected results.

Adjustment of the amplitude can be done by varying the xamp argument, which acts as a multiplier.

Notice that both xamp and xfreq can use k-rate as well as a-rate signals. Both arguments must use variables of the same rate, or sfplay3m will not work correctly. ipreindex must contain the number of a previously assigned preset, or Csound will crash.

The ioffset parameter allows the sound to start from a sample different than the first one. The user should make sure that its value is within the length of the specific sound. Otherwise, Csound will probably crash.

The ienv parameter enables and determines the type of amplitude envelope used. The default value is 0, or no envelope. If ienv is set to 1, the attack and decay portions are linear. If set to 2, the attack is linear and the decay is exponential. The release portion of the envelope has not yet been implemented.

sfplay3m is a mono version of sfplay3. It should be used with mono preset, or with the stereo presets in which stereo output is not required. It is faster than sfplay3.

sfplay3m is also a cubic-interpolation version of sfplaym. Difference of sound-quality is noticeable specially in bass-frequency-transposed samples. In high-freq-transposed samples the difference is less noticeable, and I suggest to use linear-interpolation versions, because they are faster.

These opcodes only support the sample structure of SF2 files. The modulator structure of the SoundFont2 format is not supported in Csound. Any modulation or processing to the sample data is left to the Csound user, bypassing all restrictions forced by the SF2 standard.


Here is an example of the sfplay3m opcode. It uses the file sfplay3m.csd.

Example 991. Example of the sfplay3m opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

; Select audio/midi flags here according to platform
-odac  ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o sfplay3m.wav -W ;;; for file output any platform

; By  Menno Knevel - 2020

sr = 44100 
ksmps = 32
nchnls = 2
0dbfs  = 1 

gisf	sfload	"07AcousticGuitar.sf2"
	sfplist	gisf
	sfpassign 0, gisf    ; assign the preset to number 00 

instr 1	

inum    =   p4
ivel    =   p5
kamp	linsegr	1, 1, 1, .1, 0
kamp	= kamp/900000 * ivel			;scale amplitude and make velocity dependent
kfreq	=	1						;do not change freq from sf
aout	sfplay3m ivel, inum, kamp, p6, 0, 1	   ;preset index = 0, set flag to frequency instead of midi pitch
	outs	aout, aout

i1 0 1 60 127 400   ; take the samples from key 60 and set new frequency
i1 + 1 60 90   <
i1 + 1 60 60   <
i1 + 1 60 10  200


See also


More information on soundfonts is in the Floss Manuals: https://flossmanual.csound.com/midi/reading-midi-files

For other information on soundfonts look in the Wikipedia: http://en.wikipedia.org/wiki/Soundfont


Author: Gabriel Maldonado
May 2000

New in Csound Version 4.07

New optional parameter ienv in version 5.09