CODEWITHSUNDEEP
iossynchronizationclockaudio-playercoremidi
user1195202
user1195202

Reputation: 1443

IOS MusicSequence & MusicPlayer external midi clock sync

I'm using MusicPlayer to play notes in MusicSequence:

NewMusicSequence(&sequence);
MusicSequenceFileLoad(sequence, (__bridge CFURLRef) midiFileURL, 0, 0);

// Set the endpoint of the sequence to be our virtual endpoint
MusicSequenceSetMIDIEndpoint(sequence, virtualEndpoint);

// Create a new music player
MusicPlayer  p;

// Initialise the music player
NewMusicPlayer(&p); 


// Load the sequence into the music player
MusicPlayerSetSequence(self.player, sequence);
// Called to do some MusicPlayer setup. This just
// reduces latency when MusicPlayerStart is called
MusicPlayerPreroll(self.player);

-(void)play {
   MusicPlayerStart(self.player);
}

It's working well, I would say very well, but I do not want to use the internal clock.

How can I use the external midi clock?
Or maybe I can somehow move the playing cursor with a clock.

Upvotes: 3

Views: 505

Answers (1)

johndpope
johndpope

Reputation: 5257

You can use MusicSequenceSetMIDIEndpoint(sequence,endpointRef);

then create a midi clock

 CAClockRef mtcClockRef;
    OSStatus err;
      err = CAClockNew(0, &mtcClockRef);
            if (err != noErr) {
                NSLog(@"\t\terror %ld at CAClockNew()", err);
            }
            else {
                CAClockTimebase timebase = kCAClockTimebase_HostTime;
                UInt32 size = 0;
                size = sizeof(timebase);
                err = CAClockSetProperty(mtcClockRef, kCAClockProperty_InternalTimebase, size, &timebase);
                if (err)
                    NSLog(@"Error setting clock timebase");

set the sync mode

UInt32 tSyncMode = kCAClockSyncMode_MIDIClockTransport;
                size = sizeof(tSyncMode);
                err = CAClockSetProperty(mtcClockRef, kCAClockProperty_SyncMode, size, &tSyncMode);

then set the clock to use the midi end point

 err = CAClockSetProperty(mtcClockRef, kCAClockProperty_SyncSource, sizeof(endpointRef), endpointRef);

There's some reference code VVMIDINode here - > https://github.com/mrRay/vvopensource/blob/master/VVMIDI/FrameworkSrc/VVMIDINode.h

Upvotes: 1

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