.TH OPL3 1
.SH NAME
opl3 \- OPL3 chip emulator
.SH SYNOPSIS
.B opl3
[
.B -r
.I rate
] [
.I file
]
.SH DESCRIPTION
.I Opl3
is an emulator of a single Yamaha 262 chip, also known as
.SM OPL3.
.PP
The emulated chip is programmed by a stream of commands either from
.I file
or from standard in.
It then synthesizes stereo 16-bit little-endian PCM samples
at the chip's sampling rate, 49.716 kHz,
resamples them to
.IR audio (3)'s
default 44.1 kHz rate,
and writes them to standard out.
.PP
Commands are 5 bytes wide, in little-endian byte order:
.PP
.RS
.IR register [2]
.IR value [1]
.IR delay [2]
.RE
.PP
Each command specifies a
.I value
to be written to an
.SM OPL3
chip
.IR register ,
modifying its internal state.
.PP
The
.I delay
field provides timing.
It is a multiple of a command period, during which the
.SM OPL3
chip may be sampled before processing the next command.
The period itself is the inverse of the input stream's sampling rate,
by default the same as the chip's output sampling rate.
The
.B -r
parameter
sets the input sampling rate.
.SH SOURCE
.B /sys/src/games/opl3
.SH "SEE ALSO"
.IR audio (3)
.PP
Yamaha
``YMF262 Manual'',
1994.
.PP
V. Arnost
``Programmer's Guide to Yamaha YMF 262/OPL3 FM Music Synthesizer'',
version 1.12 dated Nov. 23rd 2000.
.SH HISTORY
.I Opl3
first appeared in 9front (July, 2018), based on
.I ymf262.c
from the Multiple Arcade Machine Emulator (
.SM MAME
).