How can I extrack the Tempo from a Track chunk?

[fbarrera]

I'm creating a rhythm game for Unity, and I'd like to extract some information from the MidiEvents that have been triggered. If I loop through the track chunks in the midi file, I can find the midiEvents that are being triggered.

The thing is, I actually find the SetTempo event, and if I print it with ToString() method, the following thing get in the output:

Set Tempo (468750)

Question is: how do I get this number? Isn't there any function like GetTempo to extract it from the chunk? Or is there a way to loop through the midi events to extract the data?

There is actually no pointer in the documentation to know how to extract the information from the TempoMap.

Thanks!

[melanchall]

First of all, with

var tempoMap = midiFile.GetTempoMap();

you can get tempo map - an object containing information about all tempo and time signature changes (please read the article in the documentation - https://melanchall.github.io/drywetmidi/articles/high-level-managing/Tempo-map.html).

Then you can get tempo at any point in the time:

var startTempo = tempoMap.GetTempoAtTime((MidiTimeSpan)0);

or you can get all tempo changes:

var tempoChanges = tempoMap.GetTempoChanges();

[melanchall]

newTempo = tempoMap.GetTempoAtTime(new MetricTimeSpan(INSERTVALUEHERE));

INSERTVALUEHERE is a number of microseconds.

But in fact I don't understand what do you want.

Now, how do I print each new tempo in real time with the void Update() function?

MidiFile.Read just reads a file immediately. There is no way to subscribe to reading process and do something when reading engine reads a MIDI event.

[LeoMassaFM]

What I wanna do is I want the track's tempo to update in game in real time as each tempo change happens.

[melanchall]

What I wanna do is I want the track's tempo to update in game in real time as each tempo change happens.

What do you mean "as each tempo change happens"? Happens where? Again, MidiFile.Read just reads a MIDI file immediately. The problem is how to calculate INSERTVALUEHERE? If so, I don't know your logic, how you start ticking and so on.

[LeoMassaFM]

I got the tempo changes with tempoMap.GetTempoChanges(), right? Now, what do I do with it? How can I get all the tempos that this GetTempoChanges got?

[melanchall]

Hmm, but in your code you have:

tempoChanges = tempoMap.GetTempoChanges();

So... what does that mean?

How can I get all the tempos that this GetTempoChanges got?

You've already got them. Maybe your question is how to get tempo from an item of this collection? If yes, what's wrong with this simple code?

foreach (var tempoChange in tempoChanges)
{
    var tempo = tempoChange.Value;
    var bpm = tempo.BeatsPerMinute;
}

Just standard C# instructions. Of course you can use LINQ on the collection too.