common-schema.json

{
    "$id": "http://example.com/common",
    "type": "object",
    "$schema": "http://json-schema.org/draft-07/schema#",
    "definitions": {
        "mediaType": {
            "type": "object",
            "properties": {
                "id" : { "type": "number" },
                "name" : { "type": "string" }},
			"additionalProperties" : false,
			"required" : [ "id", "name" ]
		},
		
        "media": {
            "type": "object",
            "properties": {
                "alternateName" : { "type": [ "string", "null" ] },
                "type" : { "type": "string" },
                "url" : { "type": "string", "format": "uri" }
            },
            "additionalProperties" : false,
            "required" : [ "alternateName","type","url" ]
        }
    }
}