davidluzgouveia / midi-parser Goto Github PK

The type used to store the meta event tempo is too small, even when converted as BPM. Since data1 is a byte and cast does not check for overflows, any value greater than 256 will result in an silent overflow.

        private static bool ParseMetaEvent(
            byte[] data,
            ref int position,
            byte metaEventType,
            ref byte data1,
            ref byte data2)
        {
            switch (metaEventType)
            {
                case (byte)MetaEventType.Tempo:
                    var mspqn = (data[position + 1] << 16) | (data[position + 2] << 8) | data[position + 3];
                    data1 = (byte)(60000000.0 / mspqn);
                    position += 4;
                    return true;

I would advise changing data1 and data2 types to int as I did.

On another note converting the tempo into BPM is confusing for a library that aims to offer a minimalist representation of MIDI events. I would suggest keeping the original MIDI value and maybe use a static function to convert it. Also the loss in precision might be unwanted for some specific use cases.

Thank you for this library, it helped me a lot.

I can get time from midi file, but How it works?
Here are the times of each note:

51
56
44
51
56
46
53

What are their meaning?

ex:

foreach(var midiEvent in track.MidiEvents)
    {
        if(midiEvent.MidiEventType == MidiEventType.NoteOn)
        {
            var channel = midiEvent.Channel;
            var note = midiEvent.Note;
            var velocity = midiEvent.Velocity;
            var noteLength = midiEvent.Length //--I want a feature like this, indicate the length of the note (noteOff time - noteOn time)
        }
    }

https://stackoverflow.com/questions/23070510/how-to-get-exact-time-of-a-midi-event

I don't know much to MIDI files but I can confirm that Time in MidiEvent.Time is not the correct time.

Is there a way to get PPQ (Pulses per quarter note)?
PPQ is reuired to transfer MIDI tick to seconds.
or is the time already transferred into seconds?

EDIT: I found the Tick per quarter note. :)
PPQ = midiFile.TicksPerQuarterNote;
Maybe you should consider write that in README.