# AUScheduleMIDIEventBlock A block to schedule MIDI events. ``` typealias AUScheduleMIDIEventBlock = (AUEventSampleTime, UInt8, Int, UnsafePointer) -> Void ``` ## Discussion The block takes the following parameters: - eventSampleTime: The sample time at which the MIDI event is to occur. When scheduling parameters during the render cycle, this time can be set to the `AUEventSampleTimeImmediate` value plus an optional buffer offset, in which case the event is scheduled at that position in the current render cycle. - cable: The virtual cable number. - length: The number of bytes of MIDI data in the provided event(s). - midiBytes: One or more valid MIDI 1.0 events, except *sysex* which must always be sent as the only event in the chunk. Running status is not allowed. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)