var some_obj = {
    image: "http://example.com/poster.jpg",
    title: "testHLS",
    width: "100%",
    aspectratio : "16:9",
    playlist: [
        {
            sources: [
                {
                    file: "http://example.com/playlist.m3u8"
                }
            ]
        }
    ],
    repeat: true
}
jwplayer( "my_media_player" ).setup(some_obj);
alert(some_obj['playlist'][0]['sources'][0]['file']);