Mediaelement.js (wordpress plugin 3.2.1) - video thumbnail is displayed blank on page load
To load the mediaelement.js thumbnail, you need to make sure preload is not set to none. For example:
<video src="myvideo.mp4" controls="controls" preload="metadata"></video>
Setting up poster = "poster.jpg" as per the example in the documentation will not necessarily work (unless you have a file named poster.jpg). Although you can set the poster attribute to the location of the image to be used as the thumbnail before uploading the video, in case the user agent does not look inside the media object.
See this answer for more information on preloading options - What are the options for preloading a media player? installation?
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