.eml is not a video format. It is the extension for email message files. I usually see this format when a second sender sends an original message as an attachment in the wake of some type of error. (The second sender may be an automatic agent within a mail server.)
Save the .eml file. Double-click on it. Mail may be able to open the file. If not, associate the .eml file with Outlook Express, Microsoft's Classic email client. Between the two applications, hopefully one will open it.
