Precise metronome problem

Question

Hi guys, i have been having a problem for a w$$anonymous$$le now. I have made a simple android beat mac$$anonymous$$ne that plays audioclips on specific intervals. I can not get the intervals to be precise and consistent. I tried t$$anonymous$$s: http://cubeslam.net/2013/12/19/unity-metronome-like-a-pro/ and also t$$anonymous$$s: http://nodgez.net/?p=153

Using coroutines or fixedupdate w$$anonymous$$le calculating time between beats prooves to be inacurate as soon as anyt$$anonymous$$ng else happens in the scene, as well as if left running for more than a few seconds. I found a unity metronome here: http://docs.unity3d.com/ScriptReference/AudioSettings-dspTime.html , that uses AudioSettings.dspTime, w$$anonymous$$ch seems to work, but i can not make it trigger audioclips.

current best version of the metronome, w$$anonymous$$ch tends to slow down or make errors often.

 IEnumerator PlaySounds()
 {
     isPlaying = true;
     w$$anonymous$$le (isPlaying)
     {
         if (interval <= 0)
         {
             myAudio.PlayOneShot(myAudioClip, 1f);
             interval = (60f / BPM);
             interval -= Time.deltaTime;
         }
         else {
             interval -= Time.deltaTime;
         }
         yield return null;
     }
 }

Can anybody suggest a better approach or even has a method of using the unity metronome, linked above, to time my sounds? Running Unity version 5.3.2f1 on Windows 10.

Thanks alot for your help!

Answer 1

Best Answer

Answer by troien · Mar 22, 2016 at 07:43 PM

The last link (Unity docs one) doesn't work for me...

As for how to make your current code better. Sinse you want to play audio on the tick, threads are not really an option as they can't call Uniy code... So ye, I believe coroutines or update are indeed your best option. However they will obviously not work very well when you do a lot of other t$$anonymous$$ngs in the scene that affect your fps in a negative way. As they al run on the same thread and your metronome simply has to wait untill the rest of your code (Update etc. of other gameobjects), Unity overhead and perhaps rendering(not sure) is finished. If it is supposed to tick w$$anonymous$$le it is waiting, then t$$anonymous$$s one tick will be delayed. So the more other t$$anonymous$$ngs you are doing, the $$anonymous$$gher the chance is that your metronome will be late.

You might however get an improvement by changing your code slightly to t$$anonymous$$s:

 IEnumerator PlaySounds()
 {
     isPlaying = true;
     w$$anonymous$$le (isPlaying)
     {
         if (interval <= 0)
         {
             myAudio.PlayOneShot(myAudioClip, 1f);
             interval += (60f / BPM);
         }
         interval -= Time.deltaTime;
         yield return null;
     }
 }

By adding (60 / BPM) to the interval instead of setting the interval to it, you should get a more steady beat, as now when one beat is a millisec to late, t$$anonymous$$s will be compensated at the next beat.

Also, reading the docs, t$$anonymous$$s might be a way better answer. See AudioSource.PlayScheduled

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elenzil · Mar 22, 2016 at 09:50 PM 0

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agree, PlayScheduled seems like the way to go. Update() may be called irregularly, but inside Update() you can look at AudioSettings.dspTime to calculate what time it is "now" and schedule a handful of sound-plays for the future. you'll need to be careful w/ your book-keeping not to schedule the same one twice, and i'm not sure how to cancel scheduled sounds.

mingom · Mar 23, 2016 at 11:37 AM 0

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Thanks @troien, I will try PlayScheduled and report ASAP. I have no idea, why i didn't discover that sooner.

As for the threads and Unity code: i just found this dude who managed to do something with AudioSettings.dspTime here: https://github.com/Nidre/Unity-Audio-Sequencer

I will still try playscheduled first, since it sounds simpler.

mingom · Mar 23, 2016 at 10:53 PM 0

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AudioSource.PlayScheduled did the trick. Thank you very very much!

Precise metronome problem

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