| Namespace | Windows.Devices.Midi2.Utilities.Sequencing |
|---|---|
| Type Name | MidiSequenceTempoChange |
| Type | WinRT Struct |
| IDL | MidiSequenceTempoChange.idl |
MidiSequenceTempoChange is one entry in the tempo map of a MidiSequence. Get them from the sequence’s TempoMap collection, which is small enough to hand over whole.
| Field | Description |
|---|---|
Tick |
Where the change takes effect |
MicrosecondsPerQuarterNote |
The tempo the way the file stores it |
BeatsPerMinute |
The same tempo, worked out as quarter notes per minute |
MicrosecondsAtTick |
Where this tick falls in time, so looking up a position doesn’t have to go through the whole map |
A file stores tempo as microseconds per quarter note, never as beats per minute, so BeatsPerMinute here is worked out from it.
It’s also always quarter notes per minute, whatever the time signature. That’s what the file format defines, and what a sequencer’s transport shows. In a time signature like 6/8, the beat you’d count or conduct is a dotted quarter note, so this number is correct but isn’t the tempo you feel. If your app shows a conductor’s tempo instead of a transport tempo, convert it yourself, using the MidiSequenceTimeSignature in effect.
Windows MIDI Services is an open source project with all source available on GitHub. We have a great community on Discord as well. Between GitHub and Discord, you should find the information you are looking for.
