Accessible names
Typically, a banner's background image is decorative and doesn't need a description. However, if the image contains text not visible elsewhere on the banner, it must be described. This ensures blind screen reader users don't miss unique content.
When using video banners with embedded text, blind users have no way to access this visual-only content. Ensure the same content is provided elsewhere on the page as an alternative for screen reader users.
Readability
For video banners with embedded text, users with low vision cannot enlarge fonts or improve contrast. Provide the same content elsewhere on the page as an alternative. Additionally, follow best practices for making text in videos accessible to users with reading difficulties (e.g., deaf or dyslexic individuals) who may read slower.
Even when text in a video is repeated on the page, visitors might not realize the content is identical. Therefore, avoid using text in videos whenever possible.
Remember that users can stop background videos using the mandatory accessibility button to concentrate better or reduce data transfer. If they do, they won't see any text embedded in the video and would also benefit from having that text repeated on the page.