What pattern or approach is best suited for de-serialising to particular concrete instances?

Given the following JSON:

    {
        "data": {
            "videos": [{
                "url": "www.youtube.com",
                "title": "YouTube"
            }, {
                "url": "www.vimeo.com",
                "title": "Vimeo"
            }]
        }
    }

If I wanted to de-serialise these objects into concrete instances, i.e.:

public class YouTubeVideo
{
    public string Url { get; set; }
    public string Title { get; set; }

    public string GetYouTubeViewCount()
    {
        //return youtube view count
    }
}

public class VimeoVideo
{
    public string Url { get; set; }
    public string Title { get; set; }

    public string GetVimeoAudience()
    {
        //return audience from video
    }
}

What is the best approach for determining the instance to create? Note: I'm not talking about how to deserialise here (i.e. with JSON.NET). I'm talking about a pattern to deal with the logic of determining a concrete instance.

A factory pattern could work that deals with the logic on determining the object to create based on some property/data within the JSON - but this would break the open/closed principle if I wanted to deal with new 'Video' types.

Alternatively I could use a mapper and configure it to map to the relevant concrete instance.

Is there a better way? (not looking for a particular language solution, just an approach / pattern)