How to receive an event at each bar?

[garcon33]

Hi,

I'd like to receive an event at each bar while playing the midi file.
Could anyone please tell me how to create an event like that?

Many thanks in advance..!
Yj

[melanchall]

Hi,

Interesting task. Can't provide an easy way, you need some extra coding here. First, declare these constants and fields:

private const int _checkFrequency = 10;

private static int _ticks = -1;
private static TimeSpan[] _barsStarts;
private static IEnumerator<TimeSpan> _barsStartsEnumerator;
private static bool _barsStartsEnumerated;

static here because I've tested the things within console app with static Main. If you have non-static class, use fields without the keyword.

Well, next:

var tickGenerator = new HighPrecisionTickGenerator();
tickGenerator.TickGenerated += OnTickGenerated;

And next:

var tempoMap = midiFile.GetTempoMap();
_barsStarts = Enumerable
    .Range(0, (int)midiFile.GetDuration<BarBeatTicksTimeSpan>().Bars)
    .Select(bar => (TimeSpan)TimeConverter.ConvertTo<MetricTimeSpan>(new BarBeatTicksTimeSpan(bar), tempoMap))
    .ToArray();
_barsStartsEnumerator = ((IEnumerable<TimeSpan>)_barsStarts).GetEnumerator();
_barsStartsEnumerated = !_barsStartsEnumerator.MoveNext();

_playback = midiFile.GetPlayback(new PlaybackSettings
{
    ClockSettings = new MidiClockSettings
    {
        CreateTickGeneratorCallback = () => tickGenerator
    }
});

And finally OnTickGenerated:

private static void OnTickGenerated(object sender, EventArgs e)
{
    _ticks++;
    if (_ticks % _checkFrequency == 0 && !_barsStartsEnumerated)
    {
        var barStart = _barsStartsEnumerator.Current;
        if ((TimeSpan)_playback.GetCurrentTime<MetricTimeSpan>() > barStart)
        {
            // WE'RE ON BAR START; DO ACTIONS HERE
            // for example, print new bar index:
            var bar = _playback.GetCurrentTime<BarBeatTicksTimeSpan>().Bars;
            Console.WriteLine($"Bar {bar} reached!");

            _barsStartsEnumerated = !_barsStartsEnumerator.MoveNext();
        }
    }
}

[garcon33]

Hi melanchall,

Thanks a lot for your quick reply!

I just tried your method!
I can receive an event when each bar started, but it doesn't play any sounds...

Did you get sounds on your side?

Thanks,
Yj

[melanchall]

It's because I didn't pass output device in GetPlayback. Just pass it like you did in another your discussion.

[garcon33]

You're right.. I forgot to add output device!
Now it works very well! Thanks again:)