A snippet of code from the Washington Post's internal story API to process iframes.

parse.py

 # And now we get into the fun rando ones
        # First up, vevo! https://www.eff.org/https-everywhere/atlas/domains/vevo.com.html
        elif 'http://cache.vevo.com/' in iframe['src']:
            iframe['src'] = iframe['src'].replace('http://cache.vevo.com/', 'https://scache.vevo.com/')
        # Next up YouTube
        elif 'http://www.youtube.com/' in iframe['src']:
            iframe['src'] = iframe['src'].replace('http://www.youtube.com/', 'https://www.youtube.com/')
        # Gfycat http://gfycat.com
        elif 'http://gfycat.com' in iframe['src']:
            iframe['src'] = iframe['src'].replace('http://gfycat.com/', 'https://gfycat.com/')
        elif 'http://www.dailymotion.com' in iframe['src']:
            iframe['src'] = iframe['src'].replace('http://www.dailymotion.com', 'https://www.dailymotion.com')
        elif 'http://apps.washingtonpost.com' in iframe['src']:
            iframe['src'] = iframe['src'].replace('http://apps.washingtonpost.com', '//www.washingtonpost.com/apps/')
        elif 'http://data-wrapper.s3.amazonaws.com' in iframe['src']:
            iframe['src'] = iframe['src'].replace('http://data-wrapper.s3.amazonaws.com', 'https://data-wrapper.s3.amazonaws.com')
        elif 'http://www.washingtonpost.com/wp-srv/graphics/' in iframe['src']:
            iframe['src'] = iframe['src'].replace('http://www.washingtonpost.com/wp-srv/graphics/', '//www.washingtonpost.com/wp-srv/graphics/')
        elif 'http://www.washingtonpost.com/graphics/' in iframe['src']:
            iframe['src'] = iframe['src'].replace('http://www.washingtonpost.com/graphics/', '//www.washingtonpost.com/graphics/')
        elif '//cdnapisec.kaltura.com/' in iframe['src']:
            iframe.decompose()
        elif 'http://' in iframe['src']:
            iframe.decompose()

Use a mapper... =(

You could just remove the "http:" part