Question

JavaScript => public function SetScheduledEndTime(time: double): void;
C# => public void SetScheduledEndTime(double time);

Parameters 参数

time	Time in seconds. 时间，单位秒。

Description 描述

Changes the time at which a sound that has already been scheduled to play will end. Notice that depending on the timing not all rescheduling requests can be fulfilled.

更改已定时播放的声音将结束的时间。注意取决于时间，不是所有的重定时请求被满足。

Note that the time specified is still a time on the absolute time-line, meaning that the sound will stop when reaching that time, regardless of when it was started. So if you have a 5 second long sound and want it to play at time T and stop after 3 seconds (i.e. silencing the last 2 seconds of the sound), you need to specify the end time to be T+3. This function is useful in music systems to overcome the discontinuities in signals that frame-based lossy codecs cause.

请注意，指定的时间仍然是绝对时间线的时间，意味着当到达时间时声音将停止，不管什么时候开始。因此，如果你有个5秒长声音，想要在T时间播放，并在3秒后停止（例如，声音的最后2秒消音），你必须指定结束时间是T+3。这个函数用于音乐系统克服基于帧的有损编码解码器的信号不连续性是很有用的。

JavaScript:

// Demonstration of a tool that cuts up a clip into two clips with a short overlaps, then stitches them together at playback time.
// An overlap of 0.2 seconds is used meaning that the clip will be cut onto two portions of approximately the same size,
// but with the first sound having 0.2s of the sound after the cut and the second clip starting with
// 0.2s of the sound before the cut.
// The idea is then to play cut1 from its start to the cut point and then stop playback, i.e. not playing
// the 0.2s overlap (this happens via the SetScheduledEndTime), then play cut2 starting 0.2s into the sound and
// playing it to the end.
// While this may seem unnecessarily complicated to do this in the case of uncompressed sounds, you can now use
// the SavWav code from https://gist.github.com/2317063 to save the generated clips into new assets,
// run the program once with a specified sourceClip and the script will generate "cut1.wav" and "cut2.wav".
// These can now be imported into Unity as assets and changed to compressed sounds.
// Since psychoacoustic compression severely alters the waveforms and frequency content of sounds and
// furthermore operates in a block-based fashion, it would cause very noticeable pops and clicks if we didn't
// have the sound data after and before the cut point. By having it, even though we are not playing it, the decoder is "warmed up",
// i.e. it has matching frequency content before and after the transition, so at least the
// frequency spectrum will be more or less the same before and after the transition and so the click will be less audible
// than if we had just cut up the sound without the 0.2s overlap regions.
// This method may also be combined with cross-fading in order to further smoothen out any remaining artifacts.
 
@script RequireComponent(AudioSource)
 
public var sourceClip : AudioClip;
 
private var audio1 : AudioSource;
private var audio2 : AudioSource;
private var cutClip1 : AudioClip;
private var cutClip2 : AudioClip;
private var overlap : float = 0.2f;
private var len1 : int = 0;
private var len2 : int = 0;
 
function Start ()
{
	var child : GameObject;
	child = new GameObject("Player1"); child.transform.parent = gameObject.transform; audio1 = child.AddComponent.<AudioSource>();
	child = new GameObject("Player2"); child.transform.parent = gameObject.transform; audio2 = child.AddComponent.<AudioSource>();
	var overlapSamples : int;
	if(sourceClip != null)
	{
		len1 = sourceClip.samples / 2;
		len2 = sourceClip.samples - len1;
		overlapSamples = overlap * sourceClip.frequency;
		cutClip1 = AudioClip.Create ("cut1", len1 + overlapSamples, sourceClip.channels, sourceClip.frequency, false, false);
		cutClip2 = AudioClip.Create ("cut2", len2 + overlapSamples, sourceClip.channels, sourceClip.frequency, false, false);
		var smp1 = new float [(len1 + overlapSamples) * sourceClip.channels];
		var smp2 = new float [(len2 + overlapSamples) * sourceClip.channels];
		sourceClip.GetData(smp1, 0);
		sourceClip.GetData(smp2, len1 - overlapSamples);
		cutClip1.SetData(smp1, 0);
		cutClip2.SetData(smp2, 0);
		//SavWav.Save("cut1.wav", cutClip1);
		//SavWav.Save("cut2.wav", cutClip2);
	}
	else
	{
		overlapSamples = overlap * cutClip1.frequency;
		len1 = cutClip1.samples - overlapSamples;
		len2 = cutClip2.samples - overlapSamples;
	}
}
 
function OnGUI()
{
	if (GUI.Button(new Rect(10, 50, 230, 40), "Trigger source"))
		audio1.PlayOneShot(sourceClip);
	if (GUI.Button(new Rect(10, 100, 230, 40), "Trigger cut 1"))
		audio1.PlayOneShot(cutClip1);
	if (GUI.Button(new Rect(10, 150, 230, 40), "Trigger cut 2"))
		audio1.PlayOneShot(cutClip2);
	if (GUI.Button(new Rect(10, 200, 230, 40), "Play stitched"))
	{
		audio1.clip = cutClip1;
		audio2.clip = cutClip2;
		var t0 = AudioSettings.dspTime + 3.0;
		var clipTime1 : double = len1;
		clipTime1 /= cutClip1.frequency;
		audio1.PlayScheduled(t0);
		audio1.SetScheduledEndTime(t0 + clipTime1);
		Debug.Log("t0 = " + t0 + ", clipTime1 = " + clipTime1 + ", cutClip1.frequency = " + cutClip1.frequency);
		Debug.Log("cutClip2.frequency = " + cutClip2.frequency + ", samplerate = " + AudioSettings.outputSampleRate);
		audio2.PlayScheduled(t0 + clipTime1);
		audio2.time = overlap;
	}
}

C#:

using UnityEngine;
using System.Collections;
 
// While this may seem unnecessarily complicated to do this in the case of uncompressed sounds, you can now use
// the SavWav code from https://gist.github.com/2317063 to save the generated clips into new assets,
// run the program once with a specified sourceClip and the script will generate "cut1.wav" and "cut2.wav".
// These can now be imported into Unity as assets and changed to compressed sounds.
// Since psychoacoustic compression severely alters the waveforms and frequency content of sounds and
// furthermore operates in a block-based fashion, it would cause very noticeable pops and clicks if we didn't
// have the sound data after and before the cut point. By having it, even though we are not playing it, the decoder is "warmed up",
// i.e. it has matching frequency content before and after the transition, so at least the
// frequency spectrum will be more or less the same before and after the transition and so the click will be less audible
// than if we had just cut up the sound without the 0.2s overlap regions.
// This method may also be combined with cross-fading in order to further smoothen out any remaining artifacts.
[RequireComponent(typeof(AudioSource))]
public class ExampleClass : MonoBehaviour
{
	public AudioClip sourceClip;
	private AudioSource audio1;
	private AudioSource audio2;
	private AudioClip cutClip1;
	private AudioClip cutClip2;
	private float overlap = 0.2F;
	private int len1 = 0;
	private int len2 = 0;
	void Start()
	{
		GameObject child;
		child = new GameObject("Player1");
		child.transform.parent = gameObject.transform;
		audio1 = child.AddComponent<AudioSource>();
		child = new GameObject("Player2");
		child.transform.parent = gameObject.transform;
		audio2 = child.AddComponent<AudioSource>();
		int overlapSamples;
		if (sourceClip != null)
		{
			len1 = sourceClip.samples / 2;
			len2 = sourceClip.samples - len1;
			overlapSamples = (int)(overlap * sourceClip.frequency);
			cutClip1 = AudioClip.Create("cut1", len1 + overlapSamples, sourceClip.channels, sourceClip.frequency, false, false);
			cutClip2 = AudioClip.Create("cut2", len2 + overlapSamples, sourceClip.channels, sourceClip.frequency, false, false);
			float[] smp1 = new float[(len1 + overlapSamples) * sourceClip.channels];
			float[] smp2 = new float[(len2 + overlapSamples) * sourceClip.channels];
			sourceClip.GetData(smp1, 0);
			sourceClip.GetData(smp2, len1 - overlapSamples);
			cutClip1.SetData(smp1, 0);
			cutClip2.SetData(smp2, 0);
		}
		else
		{
			overlapSamples = (int)overlap * cutClip1.frequency;
			len1 = cutClip1.samples - overlapSamples;
			len2 = cutClip2.samples - overlapSamples;
		}
	}
	void OnGUI()
	{
		if (GUI.Button(new Rect(10, 50, 230, 40), "Trigger source"))
			audio1.PlayOneShot(sourceClip);
 
		if (GUI.Button(new Rect(10, 100, 230, 40), "Trigger cut 1"))
			audio1.PlayOneShot(cutClip1);
 
		if (GUI.Button(new Rect(10, 150, 230, 40), "Trigger cut 2"))
			audio1.PlayOneShot(cutClip2);
 
		if (GUI.Button(new Rect(10, 200, 230, 40), "Play stitched"))
		{
			audio1.clip = cutClip1;
			audio2.clip = cutClip2;
			double t0 = AudioSettings.dspTime + 3.0F;
			double clipTime1 = len1;
			clipTime1 /= cutClip1.frequency;
			audio1.PlayScheduled(t0);
			audio1.SetScheduledEndTime(t0 + clipTime1);
			Debug.Log("t0 = " + t0 + ", clipTime1 = " + clipTime1 + ", cutClip1.frequency = " + cutClip1.frequency);
			Debug.Log("cutClip2.frequency = " + cutClip2.frequency + ", samplerate = " + AudioSettings.outputSampleRate);
			audio2.PlayScheduled(t0 + clipTime1);
			audio2.time = overlap;
		}
	}
}

Note: If possible create clips that overlap, and use the scheduled end time for the first, and AudioSource.time for the second to trim out the overlapped part, as the example above shows.

注意：上述例子,如果可能的话，创建剪辑重叠，为第一个并使用定时的结束时间，为第二个用audiosource.time来修剪重叠部分。

AudioSource 音频源