Audio play from Start() has audio.time ahead of Time.timeSinceLevelLoad

[x4637x]

Hi,

I’ve encounter some wired issue about AudioSource playing an audio clip.
I have an audio source that will play an audio clip after level was loaded.
But when I check it’s current playing track time using : AudioSource.timeSamples/AudioSource.clip.frequency, it tells me that the track time is ahead of Time.timeSinceLevelLoaded.
I understand I’ve some small difference cause by frame time difference, but around 0.25s ahead of Time.timeSinceLevelLoaded is really strange.
Here are a simple graph of how my audio playing components link to each others.

GameManager.cs :

    public class GameManager : MonoBehaviour
    {
        public GameObject Player;
        public AudioSource BGM;
        public static GameManager instance;
        bool beatCheck;
        float checkBeat = 1f;
        public void Awake()
        {
            if (instance == null) { instance = this; } else if (instance != this) { Destroy(gameObject); }
        }

        public void Update()
        {
            float BGMTime = BGM.timeSamples / (float)BGM.clip.frequency;
            float BGMBeat = BGMTime / 60f * 140f;
            
            if (BGMBeat >= checkBeat && !beatCheck) {
                Debug.LogFormat(gameObject, "At time since level loaded: [{1}s], beat : [{0}beat/ {6}s], at BGM time : [{2}s/ {3}beat], diff is [{4}s/ {5}beat]", Beater.instance.GetCurrBeat(), Time.timeSinceLevelLoad, BGMTime, BGMBeat, BGMTime - Time.timeSinceLevelLoad, (BGMTime - Time.timeSinceLevelLoad) / 60f * 140f, Beater.instance.BeatToSecond(Beater.instance.GetCurrBeat()));
                
                checkBeat += 1f;
            }
        }

Beater’s Update (Using 140 BPM):

        public void Update()
        {
            timer += Time.deltaTime;
            if (!GameManager.instance.BGM.isPlaying) {
                GameManager.instance.BGM.Play();
                Debug.LogFormat(gameObject, "BGM play at [{0}s /{1} beat /{2} s]", Time.timeSinceLevelLoad, GetCurrBeat(), Time.time);
            }
            SetCurrBeat(timer * GetCurrBPM() / 60f);
        }

And here is some of the log messages I’ve got after running the game :

BGM play at [0s /0 beat /2.190357 s]
Main menu : loading completed !
At time since level loaded: [0.2356176s], beat : [0.6278816beat/ 0.2690921s], at BGM time : [0.4479819s/ 1.045291beat], diff is [0.2123643s/ 0.4955166beat]
At time since level loaded: [0.6497393s], beat : [1.594166beat/ 0.6832138s], at BGM time : [0.8746485s/ 2.040847beat], diff is [0.2249092s/ 0.5247881beat]
At time since level loaded: [1.080409s], beat : [2.599062beat/ 1.113884s], at BGM time : [1.301315s/ 3.036402beat], diff is [0.2209058s/ 0.5154468beat]
At time since level loaded: [1.511001s], beat : [3.603776beat/ 1.544475s], at BGM time : [1.727982s/ 4.031958beat], diff is [0.2169809s/ 0.5062888beat]
At time since level loaded: [1.942202s], beat : [4.609913beat/ 1.975677s], at BGM time : [2.175986s/ 5.077302beat], diff is [0.2337841s/ 0.5454962beat]
At time since level loaded: [2.355902s], beat : [5.575208beat/ 2.389375s], at BGM time : [2.581315s/ 6.023069beat], diff is [0.2254131s/ 0.5259638beat]
At time since level loaded: [2.786634s], beat : [6.580248beat/ 2.820106s], at BGM time : [3.007982s/ 7.018624beat], diff is [0.2213476s/ 0.5164776beat]
At time since level loaded: [3.200802s], beat : [7.546638beat/ 3.234273s], at BGM time : [3.434649s/ 8.01418beat], diff is [0.2338469s/ 0.5456428beat]
At time since level loaded: [3.631663s], beat : [8.551977beat/ 3.665133s], at BGM time : [3.861315s/ 9.009735beat], diff is [0.2296522s/ 0.5358551beat]

[x4637x]

**Update : **
Currently solution is to delay the moment when LevelPlayer set GameManager to enable. Now calling it at Update() within LevelPlayer with condition of receiving player input.
Which now have the result looking right :

[Time since game start : 6.041576s] At time since level loaded: [7.861309s], beat : [14.08078beat/ 6.03462s], at BGM time : [6.015986s/ 14.0373beat/ sample time : 6.015s], diff is [-0.02558994s/ -0.05970987beat]

@NorthStar79