Tried with default theme: Yes

Tried with all other plugins disabled: Yes

Browser version: Chrome 88.0.4324.96 and Firefox

Shortcode/URL with the issue: https://youtu.be/njiv6PfeiXs

When embedding an upcoming live-video with arve the video size is to high (looks like 4:3 and not 16:9) and the thumbnail is not scaled down to a width of 100%.

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