Describe the issue
In chrome-based browsers, when video is longer than 35 minutes, time-bar previews are shown as empty rectangles.

To Reproduce
Steps to reproduce the issue:

1. Upload video 35+ minutes long
2. Play it
3. Move mouse pointer to the middle of the time-bar control

Expected behavior
A preview thumbnail shows up.

Actual behaviour
A preview thumbnail appears as empty transparent rectangular.

Screenshots

Environment (please complete the following information):

• OS: Windows 10
• Installation method: server install
• Browser Google Chrome Version 120.0.6099.200 (Official Build) (64-bit)

Additional context
The issue doesn't reproduce in Firefox, nor in Vivaldy.
The issue is reported to take place in some other chrome-based browsers.

This seems to be a hard-to-fix issue in chrome with rendering large background images. It is reasonable to use another implementation of preview, operating with collection of smaller images, like youtube does.