AudioSource.SetScheduledEndTime

Parameters

Description

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.

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.

// 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;
	}
}

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.