| Namespace | Windows.Devices.Midi2.Transports.Rtp |
|---|---|
| Type Name | MidiRtpOfflineRetention |
| Type | WinRT Enumeration (a 32-bit unsigned or signed integer) |
| IDL | MidiRtpOfflineRetentionEnum.idl |
Controls what happens to the MIDI endpoint for a connection this PC makes when the remote device goes away. That’s when it’s switched off, loses its network connection, or stops answering.
Any value greater than zero is a number of seconds, so this enumeration only names the values that aren’t an amount of time. Because of that, the API takes and returns a plain Int32, not this type. Use these named values for the special cases, and a number from 1 to 86400 for a delay.
Added in version 2 of MidiTransportsRtpApiContract.
| Value | Numeric Value | Description |
|---|---|---|
KeepAlways |
-1 |
The endpoint and its MIDI 1.0 port stay until the entry is removed, turned off or disconnected. The endpoint is there as soon as the MIDI service starts, even before the remote device answers |
Immediate |
0 |
The endpoint and its MIDI 1.0 port are removed as soon as the connection ends, and created again when it comes back. This is the default |
Many apps, DAWs especially, remember their setup by port. If a device is switched off when the app starts, its port is missing, and some apps drop the device from their setup. Keeping the endpoint fixes that. The port is always there, and it starts working when the device answers.
It’s off by default because it has a cost. Messages sent while the device is away are thrown away, and the app isn’t told. An app written for WinMM or WinRT MIDI 1.0 can’t ask Windows whether a device is present, so whether the port exists is the only clue it gets.
Only an entry with AutoReconnect turned on keeps its endpoint, because only those come back by themselves. Connections that remote devices make to a host on this PC always remove their endpoint when they end.
With a number of seconds, the endpoint stays for that long after the connection ends, then it’s removed. It’s created again when the device comes back. The time counts from the connection ending, so a device that’s off when the MIDI service starts has no endpoint until it first connects.
The endpoint is removed and created again when the entry’s name, or the remote device it points at, changes. Changing only this setting doesn’t disconnect anything.
Set it with MidiRtpClientConnectConfig.OfflineRetentionSeconds, and read it from MidiRtpConfiguredClient.OfflineRetentionSeconds and MidiRtpSavedClient.OfflineRetentionSeconds. While the device is away, MidiRtpConfiguredClient.EndpointDeviceId still gives the endpoint’s id.
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.
