C# 如何使用Naudio获得midi事件的实时性
我试图阅读midi音符,并使用NAudio库提取每一个音符的实时性 我写了这段代码,但它没有正确计算时间,我使用了我发现的公式C# 如何使用Naudio获得midi事件的实时性,c#,unity3d,midi,naudio,C#,Unity3d,Midi,Naudio,我试图阅读midi音符,并使用NAudio库提取每一个音符的实时性 我写了这段代码,但它没有正确计算时间,我使用了我发现的公式 ((note.AbsTime-lastTempoEvent.AbsTime)/midi.ticksPerQuarterNote)*tempo+lastTempoEvent.RealTime 守则: var strictMode = false; var mf = new MidiFile("Assets/Audios/Evangelion Midi.mi
((note.AbsTime-lastTempoEvent.AbsTime)/midi.ticksPerQuarterNote)*tempo+lastTempoEvent.RealTime
守则:
var strictMode = false;
var mf = new MidiFile("Assets/Audios/Evangelion Midi.mid", strictMode);
mf.Events.MidiFileType = 0;
List<MidiEvent> midiNotes = new List<MidiEvent>();
List<TempoEvent> tempoEvents = new List<TempoEvent>();
for (int n = 0; n < mf.Tracks; n++)
{
foreach (var midiEvent in mf.Events[n])
{
if (!MidiEvent.IsNoteOff(midiEvent))
{
midiNotes.Add(midiEvent);
TempoEvent tempoE;
try { tempoE = (TempoEvent)midiEvent; tempoEvents.Add(tempoE);
Debug.Log("Absolute Time " + tempoE.AbsoluteTime);
}
catch { }
}
}
}
notesArray = midiNotes.ToArray();
tempoEventsArr = tempoEvents.ToArray();
eventsTimesArr = new float[notesArray.Length];
eventsTimesArr[0] = 0;
for (int i = 1; i < notesArray.Length; i++)
{
((notesArray[i].AbsoluteTime - tempoEventsArr[tempoEventsArr.Length - 1].AbsoluteTime) / mf.DeltaTicksPerQuarterNote)
* tempoEventsArr[tempoEventsArr.Length - 1].MicrosecondsPerQuarterNote + eventsTimesArr[i-1];
}
var stricmode=false;
var mf=新的Midi文件(“Assets/Audios/Evangelion Midi.mid”,strictMode);
mf.Events.MidiFileType=0;
List midiNotes=新列表();
List tempoEvents=new List();
对于(int n=0;n
我得到的这些显然是不正确的
有人知道我错了吗?在这里看到有人使用MIDI真是太好了 参考代码中的
note.AbsTime-lastTempoEvent.AbsTime
部分在您这方面的实现不正确
此代码中的lastTempoEvent
变量不能表示midi文件中的最后一次节奏更改(正如您使用notesArray[i].AbsoluteTime-tempoEventsArr[tempoEventsArr.Length-1].AbsoluteTime实现的那样)
参考代码试图做的是获取当前注释
时的节奏(可能通过将上次出现的节奏更改事件存储在此变量中),同时代码减去整个midi文件中最近一次节奏更改的绝对时间。这是负数的根本原因(如果在当前音符之后有任何节奏变化)
旁注:我还建议保留备忘事件的时间安排。如果你不知道便笺何时发布,你如何关闭它?
试试这个。我对它进行了测试,效果良好。请仔细阅读内联评论
注意安全
static void CalculateMidiRealTimes()
{
var strictMode = false;
var mf = new MidiFile("C:\\Windows\\Media\\onestop.mid", strictMode);
mf.Events.MidiFileType = 0;
// Have just one collection for both non-note-off and tempo change events
List<MidiEvent> midiEvents = new List<MidiEvent>();
for (int n = 0; n < mf.Tracks; n++)
{
foreach (var midiEvent in mf.Events[n])
{
if (!MidiEvent.IsNoteOff(midiEvent))
{
midiEvents.Add(midiEvent);
// Instead of causing stack unwinding with try/catch,
// we just test if the event is of type TempoEvent
if (midiEvent is TempoEvent)
{
Debug.Write("Absolute Time " + (midiEvent as TempoEvent).AbsoluteTime);
}
}
}
}
// Now we have only one collection of both non-note-off and tempo events
// so we cannot be sure of the size of the time values array.
// Just employ a List<float>
List<float> eventsTimesArr = new List<float>();
// we introduce this variable to keep track of the tempo changes
// during play, which affects the timing of all the notes coming
// after it.
TempoEvent lastTempoChange = null;
for (int i = 0; i < midiEvents.Count; i++)
{
MidiEvent midiEvent = midiEvents[i];
TempoEvent tempoEvent = midiEvent as TempoEvent;
if (tempoEvent != null)
{
lastTempoChange = tempoEvent;
// Remove the tempo event to make events and timings match - index-wise
// Do not add to the eventTimes
midiEvents.RemoveAt(i);
i--;
continue;
}
if (lastTempoChange == null)
{
// If we haven't come accross a tempo change yet,
// set the time to zero.
eventsTimesArr.Add(0);
continue;
}
// This is the correct formula for calculating the real time of the event
// in microseconds:
var realTimeValue =
((midiEvent.AbsoluteTime - lastTempoChange.AbsoluteTime) / mf.DeltaTicksPerQuarterNote)
*
lastTempoChange.MicrosecondsPerQuarterNote + eventsTimesArr[eventsTimesArr.Count - 1];
// Add the time to the collection.
eventsTimesArr.Add(realTimeValue);
Debug.WriteLine("Time for {0} is: {1}", midiEvents.ToString(), realTimeValue);
}
}
static void CalculateMidiRealTimes()
{
var-strictMode=false;
var mf=新的MIDI文件(“C:\\Windows\\Media\\onestop.mid”,strictMode);
mf.Events.MidiFileType=0;
//只有一个集合用于非备忘和节奏变化事件
列表事件=新列表();
对于(int n=0;n
编辑:
计算实际时间时的除法是int/float,当事件之间的滴答声小于每季度音符的增量滴答声时,结果为零
以下是使用精度最高的数字类型decimal计算值的正确方法
midi歌曲onestop.midİ的长度为4:08(248秒),我们的最终事件实时时间为247.3594906770833
static void CalculateMidiRealTimes()
{
var strictMode = false;
var mf = new MidiFile("C:\\Windows\\Media\\onestop.mid", strictMode);
mf.Events.MidiFileType = 0;
// Have just one collection for both non-note-off and tempo change events
List<MidiEvent> midiEvents = new List<MidiEvent>();
for (int n = 0; n < mf.Tracks; n++)
{
foreach (var midiEvent in mf.Events[n])
{
if (!MidiEvent.IsNoteOff(midiEvent))
{
midiEvents.Add(midiEvent);
// Instead of causing stack unwinding with try/catch,
// we just test if the event is of type TempoEvent
if (midiEvent is TempoEvent)
{
Debug.Write("Absolute Time " + (midiEvent as TempoEvent).AbsoluteTime);
}
}
}
}
// Switch to decimal from float.
// decimal has 28-29 digits percision
// while float has only 6-9
// https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/floating-point-numeric-types
// Now we have only one collection of both non-note-off and tempo events
// so we cannot be sure of the size of the time values array.
// Just employ a List<float>
List<decimal> eventsTimesArr = new List<decimal>();
// Keep track of the last absolute time and last real time because
// tempo events also can occur "between" events
// which can cause incorrect times when calculated using AbsoluteTime
decimal lastRealTime = 0m;
decimal lastAbsoluteTime = 0m;
// instead of keeping the tempo event itself, and
// instead of multiplying every time, just keep
// the current value for microseconds per tick
decimal currentMicroSecondsPerTick = 0m;
for (int i = 0; i < midiEvents.Count; i++)
{
MidiEvent midiEvent = midiEvents[i];
TempoEvent tempoEvent = midiEvent as TempoEvent;
// Just append to last real time the microseconds passed
// since the last event (DeltaTime * MicroSecondsPerTick
if (midiEvent.AbsoluteTime > lastAbsoluteTime)
{
lastRealTime += ((decimal)midiEvent.AbsoluteTime - lastAbsoluteTime) * currentMicroSecondsPerTick;
}
lastAbsoluteTime = midiEvent.AbsoluteTime;
if (tempoEvent != null)
{
// Recalculate microseconds per tick
currentMicroSecondsPerTick = (decimal)tempoEvent.MicrosecondsPerQuarterNote / (decimal)mf.DeltaTicksPerQuarterNote;
// Remove the tempo event to make events and timings match - index-wise
// Do not add to the eventTimes
midiEvents.RemoveAt(i);
i--;
continue;
}
// Add the time to the collection.
eventsTimesArr.Add(lastRealTime);
Debug.WriteLine("Time for {0} is: {1}", midiEvent, lastRealTime / 1000000m);
}
}
static void CalculateMidiRealTimes()
{
var-strictMode=false;
var mf=新的MIDI文件(“C:\\Windows\\Media\\onestop.mid”,strictMode);
mf.Events.MidiFileType=0;
//只有一个集合用于非备忘和节奏变化事件
列表事件=新列表();
对于(int n=0;n