the total duration wavesurfer is giving me is wrong

[Johnrobmiller]

I have a audio file that is exactly 6.84 seconds long. I use js to and my OS to confirm that it exactly that duration. However, when I load it into Wavesurfer and call ws.getDuration(), wavesurfer is wrongly reporting that it is 6.81795 seconds long. This was causing a bug in my app that was difficult to troubleshoot.

The duration that wavesurfer is outputting ought to be exactly the same as the actual duration of the audio file.

Note: wavesurfer gets the duration wrong even if it is manually set in the options, as noted here #3656

[boristopalov]

Hey @Johnrobmiller, were you able to find a workaround for this? Running into the same issue

[shellRaining]

I try to reproduce with below code

  audioEl.value.onloadedmetadata = () => {
    console.log("audioEl", audioEl.value?.duration);
  };
  const audioContext = new AudioContext();
  const audioBuffer = await fetch(audioURL)
    .then((value) => value.blob())
    .then((blob) => blob.arrayBuffer())
    .then((buffer) => audioContext.decodeAudioData(buffer));
  console.log("audioBuffer ", audioBuffer.duration);

and result is

audioEl 13.374694
audioBuffer  13.32297052154195

found that the result of audioContext is right, and another interesting discovery is, when I change the format from mp3 to wav, the result of audioEl and audioContext will be same.

wavesurfer.js/src/wavesurfer.ts

Lines 526 to 533 in 5f32d82

	public getDuration(): number {
	let duration = super.getDuration() || 0
	// Fall back to the decoded data duration if the media duration is incorrect
	if ((duration === 0 || duration === Infinity) && this.decodedData) {
	duration = this.decodedData.duration
	}
	return duration
	}

wavesurfer tends to use the built-in duration of the audio element, which leads to inaccuracies. maybe we can exchange their order?

[aburai]

maybe this info can help HTML audio object reporting wrong file duration