Mute/UnMute a track via scripting

Hey there, I am trying to mute/unmute tracks in my timeline at runtime. I have had a good look through the code using ILSpy and I know what the problem is, I just don't know how to solve it.

Muting a previously UN-muted track by simply setting the tracks mute property seems to work fine.

But what is tricky is UN-muting a track that was muted when we started playing. I can see that this is because muted tracks dont get added to the graph. So want I want to do is trigger whatever voodoo is required to create the tracks runtime representation and add that to the directors currently playing graph.

Hopefully there is a way to do this without stopping the timeline and thus resetting everything thats already happened. I just want the new track to 'join in' and start playing its clips from wherever the playhead currently is...

 

I want to mute audio tracks via C# scripts. So I find the playbinding of this audio track, but I can not find any API to mute this Audio. Should I use the playableGraph?? Or how can I achieve that??

 

Hey @seant_unity Thanks for the tip. That might work for me in some cases, but setting the binding to nothing is not *always* the same as muting. in a Control Playable for example, the target is actually an exposedRef rather than a binding.

Do you know if there is any way to inject a new 'track' into a current graph? Like I say, removing one, thats already there doesn't *seem* to be necessary, since once the muted bool is true, it doesn't seem to perform any operations anyways- but I guess that could change- in that case I need to know how to remove one too!

Any ideas on that?

 

Still trying to figure this out. Any ideas anyone? i.e. How do I add another trackassets playable to an existing graph?

I notice in the new docs it talks about the director as being a timeline instance, so how can I add something to that instance maybe?

 

Also I am a bit confused about 'wrap modes' there doesn't seem to be one that leaves things how they are after the timeline has changed them. You'd think 'hold' but like the docs say hold keeps things as they are at the end until the timeline is interrupted (then it reverts)

 

hey @seant_unity thanks again for your help.

yep the second option (use the PlayableAPI to modify the playable graph on the fly) is what I am after help with.

Do you have any sample code you could provide as an example for how I could inject a previously muted track in to a Playable Graph when it becomes unmuted, so that it is in the graph exactly as it would have been if it had not been muted when the graph was first created?

 

@seant_unity ah man, thankyou for that, but its still not doing what i want to do, maybe i havent explained clearly enough...

what you describe there works if I want to mute tracks that were unmuted when we start and then mute/unmute them but thats not what I am after.

I want to take a track that was muted at start and add it to the playing directors timelineinstance. Like you say 'Muting a track prevents it from generating playables at all' so what I want to do is make it do whatever it *would* have done if it was unmuted when we started and add that to the timelineInstance...

when I get the directors timelinePlayable by doing something like var thisPlayable = director.playableGraph.GetRootPlayable(0); I can cast that to TimelinePlayable and then I can do things like 'AddPlayableInput' but there are no docs for that that I can find and I just cant make it do anything useful

 

Looking for something similar. I have two similar audio tracks. I want to mute one, and unmute the other at Start or Awake (or similar). The above code appears like it may help, seems rather complex though.

For my purposes, I would be fine with an Editor script that would set the tracks muted or not depending on my Build options (my custom build script would call this). Shoudn't that be easy?

 

Found this here: https://docs.unity3d.com/2017.3/Documentation/ScriptReference/Timeline.TrackAsset-muted.html

Pretty straight forward actually, I'm using it like this:

Code (CSharp):

1.  
2.         PlayableDirector director = gameObject.GetComponent<PlayableDirector>();
3.         TimelineAsset asset = director.playableAsset as TimelineAsset;
4.         foreach (var track in asset.GetOutputTracks())
5.         {
6.             if (itsTheRightTrack)
7.             {
8.                 track.muted = true;
9.             }
10.         }
11.  

(might need a director.RebuildGraph() at the end...?)

 

@SuppleTeets unless things have changed post 2017.1 I think you will find that does not work at runtime...

 

So director.rebuildgraph is what I have been looking for all along?

I'm guessing it will need some post processing if I want to unmute a track while a timeline is actually playing... I.e if the timeline is half way through playing I assume rebuild graph won't just add the unmuted track and just continue playing will it?

 

When I posted that I was 2017.3, now I'm in 2018.1 and it works in both.

 

You can just disable the animator component

 

Hey!

When I call RebuildGraph() the Unity editor crashes. Using Unity 2019.1.4f1.

The error seems to be "
Unity.exe caused an Access Violation (0xc0000005)

in module Unity.exe at 0033:7d254df8."

 

Where should I file it?

 

I would if it didn't take that long to pack and upload the report and then fail the upload with an error message. Perhaps I could share the repository and describe the steps? If so then where should I send the repo link and description?

 

@seant_unity It crashes 100% of the time when trying to mute a track from a signal. http://fogbugz.unity3d.com/default.asp?1232877_a3ujb0uutqsc9bb0

 

I was confused by the timeline recently.Finally I have found a tried-and-true method. Hope it can help you! Here is the code:

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.Playables;
3. using UnityEngine.Timeline;
4. public class timeLineMuteUnMute : MonoBehaviour
5. {
6.     PlayableDirector m_PlayableDirector;
7.     TimelineAsset m_TimelineAsset;
8.     // Start is called before the first frame update
9.     void Start()
10.     {
11.         m_PlayableDirector = FindObjectOfType<PlayableDirector>();
12.         m_TimelineAsset = (TimelineAsset)m_PlayableDirector.playableAsset;
13.     }
14.     public void MuteTrack(int inNum)
15.     {
16.         TrackAsset theTrack = m_TimelineAsset.GetOutputTrack(inNum);
17.         theTrack.muted = true;
18.         double t0 = m_PlayableDirector.time;
19.         m_PlayableDirector.RebuildGraph();
20.         m_PlayableDirector.time = t0;
21.         m_PlayableDirector.Play();
22.     }
23.     public void UnMuteTrack(int inNum)
24.     {
25.         TrackAsset theTrack = m_TimelineAsset.GetOutputTrack(inNum);
26.         theTrack.muted = false;
27.         double t0 = m_PlayableDirector.time;
28.         m_PlayableDirector.Stop();
29.         m_PlayableDirector.time = t0;
30.         m_PlayableDirector.Play();
31.         //You can also use this function ,but It will easily make your program crash especially when your timelineasset is huge.
32.         //TrackAsset theTrack = m_TimelineAsset.GetOutputTrack(inNum);
33.         //theTrack.muted = false;
34.         //double t0 = m_PlayableDirector.time;
35.         //m_PlayableDirector.RebuildGraph();
36.         //m_PlayableDirector.time = t0;
37.         //m_PlayableDirector.Play();
38.     }
39.  
40.     private void Update()
41.     {
42.         if (Input.GetKeyDown(KeyCode.M))
43.             MuteTrack(2);
44.         if (Input.GetKeyDown(KeyCode.U))
45.             UnMuteTrack(2);
46.     }
47. }

BTW，the crash when trying to mute a track from a signal really has been fixed.( the version I used is 2020.3)

 

I need to be able to disable tracks at runtime, based on whether the game is in Singleplayer mode or Multiplayer mode.

For tracks with bindings, I'm able to do what has been suggested in this tread - simply removing the Binding.

But, as mentioned above by @seant_unity , tracks that don't have Bindings (or work even with null binding, like audio) are a problem. Specifically for me right now, audio tracks and Control tracks.

All I need is the ability to somehow disable the track in any way whatsoever, at runtime. I don't need to add a new track, or "unmute" a track. Can this be done without having to RebuildGraph()? Surely there must be a way to simply disable/not process a track that exists in the current graph?

I tried muting the track, but it mutes the track on the actual timeline asset permanently. Maybe I am doing something wrong there?

Would super appreciate any help!!

 

Bump

 

Sounds like "mute" is part of the TrackAsset (so persistent). If you find no other solution, you could create custom tracks (a bit of a pain but doable) that inherit from the current track type classes, but inject a "check for mute" flag so it only calls the current behavior functionality sometimes. (I don't claim to be a Timeline scripting expert though - I am just not surprised there is no runtime-only mute functionality.)

 

It would be a nice solution but Unity engineers love to declare classes and methods as "internal", so inheritance is very hard to achieve...
Any news about the runtime muting?
It looks like that muting the actual asset track works and doesn't really change the asset: the timeline shows the track as muted even after stopping the play but it goes back as unmuted if you just restart the Editor. I guess that changes the runtime instance but it doesn't serialize the asset.

My current code looks like this (my goal is to mute tracks called "Editor" or in groups called "Editor"):

Code (CSharp):

1. var tracks = timeline.outputs
2.     .Select(track => track.sourceObject)
3.     .Where(track => track != null)
4.     .OfType<TrackAsset>();
5.  
6. tracks = tracks.Concat(tracks
7.     .SelectMany(track => track.GetChildTracks())
8. );
9.  
10. foreach (var track in tracks)
11. {
12.     var trackGroup = track.GetGroup();
13.     if (!track.muted && (track.name == "Editor" || (trackGroup != null && trackGroup.name == "Editor")))
14.     {
15.         track.muted = true;
16.         Application.quitting += onQuit;
17.  
18.         void onQuit()
19.         {
20.             track.muted = false;
21.             Application.quitting -= onQuit;
22.         }
23.     }
24. }
25.  

 

The documentation claims that a muted track will be stripped from builds, but it fail to say what happens when a track is muted at runtime in a build. I suppose the folks at Unity still haven't figured out what should happen in those cases?