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我使用这个MIDI.js库:https://github.com/mudcube/MIDI.js如何转置MIDI文件?
要加载的插件和播放MIDI文件,我这样做:
window.onload = function() {
MIDI.loadPlugin({
soundfontUrl: "./soundfont/",
instruments: [ "acoustic_grand_piano" ],
callback: function() {
MIDI.programChange(0, 0);
_player = MIDI.Player;
}
});
};
function playSong(){
_player.timeWarp = 1; // speed the song is played back
_player.loadFile(song[songid], _player.start);
_player.addListener(function(data) {
var now = data.now; // where we are now
var end = data.end; // time when song ends
var channel = data.channel; // channel note is playing on
var message = data.message; // 128 is noteOff, 144 is noteOn
var note = data.note; // the note
var velocity = data.velocity; // the velocity of the note
});
}
var songid = 0;
var song = ['data:audio/mid;base64,TVRoZAAAAA...
我的问题是,无论如何转置这个midi文件之前玩吗?基本上我想解析一个MIDI文件(无论是.mid文件还是base64格式),将所有音符改为+1,然后发送给播放器。任何方式在JavaScript中做到这一点?