REGRESSION: Distorted audio when altering playback-rate on HTMLVideoElement

• Component: Media
• Status: NEW ---

Created attachment 428823 [details]
zip version of sample files.

This behavior occurs after updating safari from 14.0 to 14.1 on macOS 11.3.1 and iOS 14.5.1.

When using safari 14.0 on macOS or iOS this problem does not occur.

Please test with https://www.w3schools.com/tags/tryit.asp?filename=tryhtml5_av_prop_playbackrate

Press the `Set video to be play in slow motion` button and listen.

When using earphones the problem is clearly audible.

Find two sample files attached.

Created attachment 428824 [details]
No distortion: macOS 11.2.3 and safari 14.0.3

Created attachment 428825 [details]
Distorted: macOS 11.3.1 and safari 14.1

[Chris Dumez]

Doesn’t seem to be using the WebAudio API, moving the Media.

[Alexey Proskuryakov]

Based on your results, this could be a regression in either Safari on in underlying system frameworks.

[Radar WebKit Bug Importer]

<rdar://problem/78118290>

I would like to add to this issue as it makes WebKit browsers barely usable for me.

The issue not only appears when slowing down videos, but audio also becomes very distorted, tinny or robotic when speeding up.

I've had this issue since I first used my MacBook in 2021 with macOS 12 and ever since, even in the current Safari Version 16.6 (18615.3.12.11.2).

It becomes especially noticeable with voices. Play back any video (e.g. on YouTube), increase the playback speed and compare the audio quality to Firefox or Chromium-based browsers.

There are also many reports of this around the Web, some examples:

- https://discussions.apple.com/thread/8504804
- https://discussions.apple.com/thread/251787801
- https://discussions.apple.com/thread/254427832
- https://orionfeedback.org/d/149-poor-audio-quality-when-playing-videos-at-non-1x-speed
- https://www.reddit.com/r/Safari/comments/uwwug7/youtube_playback_speed_sounds_robotic/
- https://www.reddit.com/r/ios/comments/hps5u2/will_the_sound_distortion_from_faster_youtube/
- https://apple.stackexchange.com/questions/431244/why-do-sped-up-videos-in-safari-have-terrible-tinny-audio-can-it-be-fixed
- ...

[Ahmad Saleem]

(In reply to yourik from comment #6)
> I would like to add to this issue as it makes WebKit browsers barely usable
> for me.
> 
> The issue not only appears when slowing down videos, but audio also becomes
> very distorted, tinny or robotic when speeding up.
> 
> I've had this issue since I first used my MacBook in 2021 with macOS 12 and
> ever since, even in the current Safari Version 16.6 (18615.3.12.11.2).
> 
> It becomes especially noticeable with voices. Play back any video (e.g. on
> YouTube), increase the playback speed and compare the audio quality to
> Firefox or Chromium-based browsers.
> 
> There are also many reports of this around the Web, some examples:
> 
> - https://discussions.apple.com/thread/8504804
> - https://discussions.apple.com/thread/251787801
> - https://discussions.apple.com/thread/254427832
> -
> https://orionfeedback.org/d/149-poor-audio-quality-when-playing-videos-at-
> non-1x-speed
> -
> https://www.reddit.com/r/Safari/comments/uwwug7/
> youtube_playback_speed_sounds_robotic/
> -
> https://www.reddit.com/r/ios/comments/hps5u2/
> will_the_sound_distortion_from_faster_youtube/
> -
> https://apple.stackexchange.com/questions/431244/why-do-sped-up-videos-in-
> safari-have-terrible-tinny-audio-can-it-be-fixed
> - ...

Can you try it with Safari Technology Preview?

Hi, thank you for making me aware.
It is, in fact, fixed in the technology preview. I believe thanks to this PR:
https://github.com/WebKit/WebKit/pull/9489