How did you get that m3u8 URL?
That link to 'A Certain Magical Index' is showing me a RTMP stream from hulu???
There is nothing wrong with your command line but you need to use a US VPN for it to work (AnonymoX only works for your browser), also for 720p use this:
Code:
ffmpeg -i "http://wpc.8c48.edgecastcdn.net/038C48/SV/480/ACMENG0001/ACMENG0001-480-,750,1500,2000,2500,K.mp4.m3u8?9b303b6c62204a9dcb5ce5fdc007bb4104d2360e7fab15f96cf6e6f44de00d9524f8493abe4eaa977233f0456fed8b5914d7a87e300bbe4683c7606312faa1058bdaea2f8deb63892245a56ed4579b236598751648f5065d483c0d38" -c copy indexstream.mkv