
meridian: OPL4 midi sequencer.
korg05rw: Driver for the Korg 05R/W. System Exclusive messages included.
opl4_gm1: Standard Opl4 soundbank. Contains GM instuments in bank 1 and an the GM drumset in drumset 1.




What is Meridian?

Meridian is a MIDI editor for MSX computers. The MIDI editor is implemented as a steptime editor. This means that the notes are not displayed in music score but as events in a grid. This kind of music notation is familliar among MSX users and is often called 'american score notation'. 
The rows of the grid are called tracks,  the columns are called steps and 16 steps is called a page. The number of pages depends on the amount of free memory. Click    for a screenshot of the editor. 
   


System requirements

Meridian runs on an MSX2 computer or higher with at least 512kB free memory, but 1 MB or more is recommended to work with most of the MIDI files. A MIDI interface like the Philips Music Module or the MSX-MIDI in the MSX Turbo-R is supported. If no MIDI interface is present, the MIDI data will be played on the Opl4. Finally MSX-DOS2 is required. The use of a mouse is recommended, but Meridian can be controlled by keyboard as well. 
Meridian can be configured by the file MERIDIAN.INI. This file contains all the preferences of the user according to memory, display, fileformats, etc. The format of the file is ASCII, so it can be edited with a texteditor like TED. Meridian must be launched from BASIC.



What's inside the tool? 

 Windowed user interface, controlled by mouse or keyboard 
 Full support of the GM1 (General MIDI Level 1) standard 
 Supported fileformats: Meridian (RW), Standard MIDI files (RW), Moonblaster (R), Soundtracker (R) 
 Selection functions 
 MIDI playback on the MIDI interface of  the Philips Music Module, MSX-MIDI and the Opl4 (Moonsound) 
 System Exclusive editor 
 MIDI driver editor 
 Lots of editors for the Opl4.  
 Online help function 



Suggestions for the development


Meridian has been in development for almost 10 years (started in 1994) and the questions is: will it ever be finished? Well,  perhaps. But for the next few years, it will still be in development. The following item are planned to be implemented:

MIDI IN functionallity for realtime MIDI recording. Because Meridian is a MIDI editor, this is a basic feature and must be present. Because MIDI IN is very time critical and the Z80 is not the fastest processor that you can imagine, a lot of work need to be done for this. The MIDI IN support in the Opl4 editors is not a realtime recorder, but an immediate MIDI IN processor, so it cannot be used as such. 
Because of the support for the Opl4, external wavetabels should be used. This isn't possible yet, but this is the next feature that will be implemented. 

Redesign Opl4 sound administration
The current approach of the Opl4, especially the PCM ROM, is not sufficient to hold the full GM set as Yamaha intented. This means that the whole administration of the Opl4 sounds needs to be redesigned. The following will be changed:

 100 FM-2 tones (in stead of the current 200) 
 50 FM-4 tones (in stead of the current 100) 
 330 PCM-ROM tones (just ROM setting, no modifications). 
 128 PCM-USR tones. 
 640 Derived PCM tones (ROM and USR. These are modifications on envelopes of existing PCM tones) 

Why is this redesign necessary? In the 'official' GM set for the Opl4, defined by Yamaha, a lot of PCM-ROM tones are used more than once, each with slide modifications in the envelope parameters. In the current situation, a PCM-ROM tone can only be used with its current setting. Changing envelope parameters will effect on all programs that uses the concerning PCM-ROM tones and this is not what we want.
