Metronome for variable bpm and variable timeSignature

[Michiel Koorn]

Hi,

I'm stuck with a metronome for my project.

I have seen the metronome example and got that working.

The problem is that I have an audio track wich can variate in bpm and in time signature.

The metronome I would like to play alongside the song needs to be adjusting to the changing bpm and changing time signatures.

I have tried working with multiple metronomes for the changing time signature and bpm's but got stuck.

Then I was thinking, since I know all timeSignatures and bpm changes before starting to play, 

Would it be possible to create a midi track in code with the metronome ticks on all the right beats etc. and play that along side the audio track? This way I can have the metronomes as complicated as I'd like.

I have been looking at AKMidi but cannot figure out where to start.

I am hoping someone can give me some feedback on this. Is this a good way to implement this metronome?

I imagine I can start a midi track like that at a certain time just as I can start the audio file at a certain time in the track and thus have both tracks synced.

If this is a good way forward, some sample code to get me started would be much appreciated.

Thanks and regards,

Michiel

[Aurelius Prochazka Ph.D.]

Synchronizing a metronome to an audio track sounds easy, but in practice it can be a bit painful.  If you do have an exactly accurate to the sample recording, the way you describe sounds reasonable.

Aure

[Michiel Koorn]

Hi Aure,

Thanks for you reply.

I have been trying to create a midi track with notes for each measure to create a metronome as described.

Using some code which I found in one of the posts here I tried this:

if let audioFileUrl = Bundle.main.url(forResource: "click", withExtension: "wav") {

           

           do {

               

               let audioFile = try AKAudioFile(forReading: audioFileUrl)

               self.midiSampler = audioFile.midiSampler

               

           } catch {

               NSLog("\(error)")

           }

       }

       

       

       let midi = AKMIDI()

       

       self.sequencer = AKSequencer(engine: AudioKit.engine)

       self.sequencer?.isAVSequencer = false

       self.midiSampler?.enableMIDI(midi.client, name: "midi sample")

       

       let track = self.sequencer?.newTrack()

       

       track?.setMIDIOutput((self.midiSampler?.midiIn)!)

       track?.setLength(AKDuration(beats: 64, tempo: 120))

       track?.add(noteNumber: 60, velocity: 127, position: AKDuration(beats:Double(1)), duration: AKDuration(beats:16.0), channel:1)

       

       self.mixer = AKMixer()

       self.mixer?.connect(self.midiSampler)

       AudioKit.output = self.mixer!

       AudioKit.start()

       

       self.sequencer?.play()

        

        

This fails miserably though.

I am hoping you can provide me with some example code for building up the midi track to get me started.

Also I wonder how I can sync the midi track with the audio file.

The audioPlayer I can play from beginTime to endTime. Can I do the same with a miditrack so that these would sync?

Thanks for your time.

Regards,

Michiel