MidiSysExMessageIsUniversalNonRealtime Property

public bool IsUniversalNonRealtime { get; }

Public ReadOnly Property IsUniversalNonRealtime As Boolean
	Get

Property Value

Universal SysEx messages are SysEx messages that are not for any one particular manufacturer, but rather, meant to be utilized by all manufacturer's products. For example, many manufacturers make digital samplers. It became desirable for manufacturers to allow exchange of waveform data between each others' products. So, a standard protocol was developed called MIDI Sample Dump Standard (SDS). Of course, since waveforms typically entail large amounts of data, SysEx messages (ie, containing over a hundred bytes each) were chosen as the most suitable vehicle to transmit the data over MIDI. But, it was decided not to use a particular manufacturer's ID for these SysEx messages. So, a universal ID was created. There are actually 2 IDs dedicated to Universal SysEx messages. There's a universal ID meant for realtime messages (ie, ones that need to be responded to immediately), and one for non-realtime (ie, ones which can be processed when the device gets around to it).

No particular manufacturer is ever assigned an ID consisting of the single byte 0x7F or 0x7E. These are reserved for Universal SysEx messages adopted by the MMA.

A general template for these two IDs was defined. After the ID byte is a SysEx Channel byte. This could be from 0 to 127 for a total of 128 SysEx channels. So, although "normal" SysEx messages have no MIDI channel like Voice Category messages do, a Universal SysEx message can be sent on one of 128 SysEx channels. This allows the musician to set various devices to ignore certain Universal SysEx messages (ie, if the device allows the musician to set its Base SysEx Channel. Most devices just set their Base Sysex channel to the same number as the Base Channel for Voice Category messages). On the other hand, a SysEx channel of 127 is actually meant to tell the device to "disregard the channel and pay attention to this message regardless".

After the SysEx channel, the next two bytes are Sub IDs which tell what the SysEx is for. There are several Sub IDs defined for particular messages. There is a Sub ID for a Universal SysEx message to set a device's master volume. (This is different than Volume controller which sets the volume for only one particular MIDI channel). There is a Sub ID for a Universal SysEx message to set a device's Pitch Wheel bend range. There are a couple of Sub IDs for some Universal SysEx messages to implement a waveform (sample) dump over MIDI etc.

Note: This member might anyhow return a valid value, since this property simply evaluates the second data byte after the initial StatusType.

Reference