Bug 249301 – Pageload: <video> initially displayed at wrong position

• Component: Media
• Status: RESOLVED CONFIGURATION CHANGED

[Frederik Riedel]

Created attachment 464038 [details]
video of the bug where the video is initially displayed at the wrong position

Hello lovely WebKit Team!

I am experiencing a strange behavior on page-load with an html5 video element.

For the first 230ms, the video element is displayed at a slightly wrong position. Please see the attached screen recording.

This is the code that I’m using to display the video element:

```html
<video width="300" height="500" preload playsinline muted loop autoplay>
    <source src="https://one-sec.app/assets/videos/one sec website animation-1.mov" type="video/mp4;codecs=hvc1">
    <source src="https://one-sec.app/assets/videos/one sec website animation-1.webm" type="video/webm">
</video>
```

Website url: https://one-sec.app

Related bug report on StackOverflow with code to reproduce: 
https://stackoverflow.com/questions/74782899/video-briefly-jumps-around-when-page-is-loaded-using-safari


Fixing this would definitely make page-loading a lot smoother, without elements jumping around.

Let me know if you need any more information!

– Frederik

[Sam Sneddon [:gsnedders]]

What version of Safari & macOS are you trying this on?

[Frederik Riedel]

Ventura 13.0 (22A380); Safari Version 16.1 (18614.2.9.1.12)

[Sam Sneddon [:gsnedders]]

(In reply to Frederik Riedel from comment #2)
> Ventura 13.0 (22A380); Safari Version 16.1 (18614.2.9.1.12)

FWIW, I can't reproduce this on 13.1 (22C65), Safari Version 16.2 (18614.3.7.1.5), on a MacBook Air (M1 2020).

[Niels Mouthaan]

I'm the author of the SO post mentioned by Frederik and based on Sam's comment, I started testing on macOS 16.1 and iOS 16.2. It indeed seems to be fixed in the latest version of (Mobile) Safari.

[Niels Mouthaan]

I'm the author of the SO post mentioned by Frederik and based on Sam's comment, I started testing on macOS 16.1 and iOS 16.2. It indeed seems to be fixed in the latest version of (Mobile) Safari.

[Alexey Proskuryakov]

Thank you for confirming!

[Frederik Riedel]

I have updated to macOS 13.1 (22C65) and Safari Version 16.2 (18614.3.7.1.5).
The bug now reproduces in a different way. See my second video.

Instead of being at the wrong position, it is not displayed zoomed in for the first fraction of the page load.

[Frederik Riedel]

Created attachment 464084 [details]
new screen recording on page load video zoom