If your talking about the pixel quality it depends on your brand. The content of the video is far more important.

You should take into account on a broader level whether an explain-er video will increase conversions verse a text based explanation due to trade offs.

Video: Visual elements help with user experience and also increase transparency with brand. The con is that search engines can't read video's and only the video description will be recognizable. (A work around is having a transcript of the video which may take away from the user experience). Also video's decrease your websites page speed.

Text: This will allow people and search engines to read your content. May decrease visitors engagement and increase bounce rate.

Solution: I have been in a position where we did an A/B text on having a video verse image to explain the concept. Turns out both performed nearly identical. We choose the image because videos hurt page speed. Page speed is a part of Google's algorithm for search engine results. Consider creating a landing page with bullet points around customers pain points (not your product/service benefits) with a CTA that takes them to your video or offer. With an explain-er video I'm guessing your offering an unique product or service.