Can generate output that can crash midiviz

[csillag]

For some MIDI file inputs we get an output which crashes the MIDIVisualizer fork.

It's not entirely obvious what is wrong with the MIDI file (if anything), because the upstream version of MIDIVisualizer can parse the generated output without any problem.

See the sample.

sample.zip

[csillag]

Apparently, just adding a new track to this input MID file is sufficient to make midiviz crash.

[csillag]

Apparently, it's the type of the MIDI file that is set wrong.

    // MIDI 0: All information in 1 track
    // MIDI 1: Multiple tracks intended to be played simultaneously
    // MIDI 2: Multiple tracks intended to be played separately

When adding a new track, we are supposed to set it from 0 to 1.