智能媒体服务这个预览json websdk转场显示不出来是咋回事不？

智能媒体服务这个预览json websdk转场显示不出来是咋回事不？
{

"VideoTracks": [

    {

        "VideoTrackClips": [

            {

                "Type": "Text",

                "Alignment": "Center",

                "Align": "center",

                "FontColorOpacity": 1,

                "X": 0,

                "Y": 0.8,

                "FontUrl": "https:\/\/cyt-static.oss-cn-beijing.aliyuncs.com\/ttf\/Alibaba-PuHuiTi-Bold.ttf",

                "Content": "步步高点读机",

                "FontSize": 103.68,

                "FontColor": "#ffffff",

                "Color": "#ffffff",

                "FontFace": {

                    "Bold": false,

                    "Italic": false,

                    "Underline": false

                },

                "TimelineIn": 0,

                "TimelineOut": 1.7,

                "AdaptMode": "AutoWrap",