It sounds like is a specific file name, likely from an iPhone or digital camera . Because this is a generic file label, it could refer to many different things depending on your context.
Once you tell me what the video is about, I can help you draft a report, analyze the content, or even help you come up with a creative story around it! IMG_9871MP4
(such as a coding demo or engineering test)? A social media trend or meme you saw online? It sounds like is a specific file name,