https://de.wikipedia.org/w/api.php?action=query&prop=imageinfo|videoinfo&format=jsonfm&iiprop=url&viprop=derivatives&titles=Datei%3AEdward%20Snowden%20speaks%20about%20NSA%20programmes%20at%20Sam%20Adams%20award%20presentation%20in%20Moscow.webm -->

{
    "servedby": "mw1208",
    "error": {
        "code": "internal_api_error_RuntimeException",
        "info": "[d543536d] Exception Caught: Attempting to add element imagerepository=shared, existing value is shared"
    }
}

Yes, of course I can just use videoinfo alone, and move the iiprop to viprop, but in code that is used for both images and videos it would be easier to always use imageinfo for the parts that are in common. Anyway, throwing an error is always bad.