People ask me this question all the time: "Does a video embedded on multiple pages count as duplicate content for SEO?"
The answer, in short, is no (with a caveat).
How Google indexes video
Google doesn't treat videos in the same way it treats other types of content. Instead of thinking of videos as discrete pieces of content that are present on some pages, Google treats video as a page element.
Therefore, Google never actually ranks videos in search results per se, but rather ranks pages, and sometimes appends a video snippet to these pages in order to indicate that a video is prominently present on the page. So, when you look through the results of Google.com/videos, every result takes you to an HTML web page, albeit one where an embedded video is featured.
This is very different from the way images are indexed and ranked.
Images, unlike videos, are considered individual pieces of media that are parsed and indexed independently from the pages they are embedded on. If you input a query in Google images, the results you'll be returned with are individual images. For each image, you're given the option to "visit page" (navigate to the page where the image is embedded) or "view image," which takes you to the URL of the individual image asset.
This second option is currently not possible with videos in Google search. It's possible that Google may change the way they treat videos in the future. One might assume that at some point you'll be able to play videos directly in a search results page, but as things stand, even for YouTube.com results, videos are just treated as rich media elements on an individual page.
What is duplicate content, and when is it an issue?
Duplicate content, through the eyes of the Google search algorithm, applies primarily at the page and domain level, e.g. Google judges websites based on whether they have a lot of duplication across the website, and whether or not a lot of the content site is material copied from other sources.
This appraisal of duplication, and subsequent devaluing of sites based on certain behaviors, initially came to the fore with Google's Panda algorithm in February 2011 (5 years ago).
Back then, it was fairly easy for websites to rank well by scraping other sources, optimizing the on-page elements for SEO, and pointing some links from other websites at the target site.
This meant that many trusted brands were being outranked by small-time affiliates and spam websites. Naturally, Google was keen to remedy this issue. Panda was designed to combat this problem and devalue low-quality websites, while ensuring sites which offered genuinely great content and user experiences consistently ranked well for informational and commercial queries.
Assessment of duplication and "thin" pages, e.g. pages with only a small amount of content on them, was a major part of Panda. This gave rise to the fear of duplication for many in the web marketing world.
As things stand today, the technology behind Panda is baked into the overall core ranking algorithm, and excessive duplication is part of a wide range of factors that affect the way your website will rank in Google search. There are three particular things to pay attention to:
Page level duplication
Page level duplication basically means that content (text, image, videos, etc.) exists on more than one page across a single website. At a small scale, this is natural and entirely appropriate (it's common to have images and snippets of text used on multiple pages across a site), but if there are too many pages that are too similar, then this can cause issues. In this case, it may appear to the Google crawler that the site is predominantly low-quality.
Duplicate pages can be caused by both editorial decisions (e.g. whitepapers that are split up and repurposed as blog posts) and technical structure (e.g. having lots of user profile pages that follow the same template).
Looking at page level duplication through the lens of video, there are some risks. Video is just another page element, like text or images, but if multiple pages include the same video and not much else to differentiate them, then this could be viewed negatively by the Google algorithm.
Domain level duplication
Sites can also be devalued when they republish or repurpose a significant amount of content that was originally published elsewhere on the web. The threshold here is quite high, as the Panda algorithm was originally designed to devalue genuinely low-quality websites. Re-publishing the occasional blog post and giving a crediting link to its source won't cause you any issues, but taking product descriptions from a third-party provider or copying and pasting directly from another site might mean your site ends up being devalued in search.
Interestingly, this principle of domain level duplication generally doesn't apply from a video standpoint. There is no negative consequence of embedding videos that are served from a third-party site (as happens with YouTube, Wistia, and the vast majority of other video platforms). Conversely, there is also no positive algorithmic benefit of using a CNAME based on your root domain (e.g. videos.wistia.com) to serve the video assets.
YouTube doesn't allow you to upload duplicate videos (to prevent piracy), and as such, has a built-in mechanism to protect against duplication. You can get away with slightly tweaking the audio or visual elements of videos in order to bypass this YouTube filter, but I really wouldn't recommend it.
When duplicate videos become problematic
Having the same videos on multiple pages isn't inherently bad. For example, if you have a product explainer video, it may well be appropriate to include it within both a blog post and a features landing page. Similarly, you may want to include testimonial videos on pages throughout your site, and this poses no issue. As a rule of thumb, as long as the pages you're embedding your video on are otherwise 70%+ unique, then there isn't any problem with embedding the video on multiple pages.
There is one common instance, however, where it can cause issues for SEO: a video library.
Many publishing sites and big brands choose to create "video libraries," which essentially function as branded microsites that offer a YouTube style experience. You can browse through all of the videos available without having to navigate through the rest of the site. Here are examples from The BBC, The Financial Times, and Calvin Klein.
There are many good reasons for creating video libraries like this from a user standpoint, but there are SEO risks involved in doing so. Most of these video libraries end up generating a lot of thin pages (pages without much content on them), which just include videos that are embedded elsewhere across a site, thus creating duplication.
At scale, this can result in ranking cannibalization for your videos in search—e.g. Google doesn't know which page to rank for the query relating to the video in question. On the extreme end, this can result in the devaluing of an entire domain.
If you want to have a video library and duplicate videos across multiple pages, then typically the best way to mitigate the search risk is to use the rel="canonical" directive, which informs Google and other search engines that one page is a duplicate, or derivative of another. By doing this, you can ensure the more valuable page (probably the original source of the video) is the one that ranks in search.
What if I embed videos on my site with Wistia and also upload them to YouTube?
Google doesn't (yet) have effective methods for matching up the videos between platforms, and so while you can't upload duplicates to YouTube, you can upload the same video to multiple platforms without necessarily causing SEO problems.
If you choose to syndicate content to social video platforms, like YouTube or Daily Motion, in addition to using Wistia to serve the videos on your website, then you can risk cannibalizing traffic to your website. In other words, you could potentially drive people to YouTube instead of your website if both pages rank for a specific query.
If you're a B2C brand that sells fast-moving consumer goods or services, and your website isn't used as a lead generation tool, then sending users to YouTube instead isn't necessarily a significant problem.
If you have a B2B brand or an Ecommerce outfit, however, then losing this traffic could negatively impact your conversions. The best thing to do is to test uploading your content to YouTube too, and carefully monitor your traffic to see if it helps or hinders your overall marketing efforts.