Can't find suitable computing-signature function from js

[abin2017]

https://www.youtube.com/s/player/2e6e57d8/tv-player-ias.vflset/tv-player-ias.js it seems use this "get_initial_function_name" function can't find right computing-signature function from tv-player-ias.js

[abin2017]

these are signatureCipher links: { "itag": 18, "mimeType": "video/mp4; codecs=\"avc1.42001E, mp4a.40.2\"", "bitrate": 424427, "width": 640, "height": 360, "lastModified": "1540946098993021", "contentLength": "12272319", "quality": "medium", "fps": 25, "qualityLabel": "360p", "projectionType": "RECTANGULAR", "averageBitrate": 424049, "audioQuality": "AUDIO_QUALITY_LOW", "approxDurationMs": "231526", "audioSampleRate": "44100", "audioChannels": 2, "signatureCipher": "s=OOqOOqAOq0QJ8wRQIhAJoK5EnCPkmM4AC1yXPIhXN9iCmFN6qhihYE4GiAlHkAAiBRTR4yxFB_XiuB_MvMAmc8dhX1xLxuE-mOrjZ8zOUQ0w%3D%3D%3D%3D&sp=sig&url=https://r3---sn-gvnuxaxjvh-v8cz.googlevideo.com/videoplayback%3Fexpire%3D1608470232%26ei%3DePreX--ZJp7k7QSX7ZeQAg%26ip%3D45.130.147.179%26id%3Do-ALD2y-ml9SgSmfTWLsMgAsrJhxXeyifGx11q-XbNj8hG%26itag%3D18%26source%3Dyoutube%26requiressl%3Dyes%26mh%3D6M%26mm%3D31%252C29%26mn%3Dsn-gvnuxaxjvh-v8cz%252Csn-bvvbax-v8ce%26ms%3Dau%252Crdu%26mv%3Dm%26mvi%3D3%26pl%3D25%26nh%3D%252CEAQ%26initcwndbps%3D808750%26vprv%3D1%26mime%3Dvideo%252Fmp4%26ns%3Dd5m8cRSyarA_Cm7w02hO920F%26gir%3Dyes%26clen%3D12272319%26ratebypass%3Dyes%26dur%3D231.526%26lmt%3D1540946098993021%26mt%3D1608448358%26fvip%3D3%26c%3DTVHTML5%26txp%3D5531432%26n%3DrfCdri435GWZqxDhX8%26sparams%3Dexpire%252Cei%252Cip%252Cid%252Citag%252Csource%252Crequiressl%252Cvprv%252Cmime%252Cns%252Cgir%252Cclen%252Cratebypass%252Cdur%252Clmt%26lsparams%3Dmh%252Cmm%252Cmn%252Cms%252Cmv%252Cmvi%252Cpl%252Cnh%252Cinitcwndbps%26lsig%3DAG3C_xAwRAIgH__tbQcxzzttcjqGt4AaGj-aYRCtWDkmKxFMc7h-02ACIHydmph4oUSdJaj1exSHCFyrjAu8dNL1S_sgMfA5ZlOx" }, { "itag": 22, "mimeType": "video/mp4; codecs=\"avc1.64001F, mp4a.40.2\"", "bitrate": 601063, "width": 1280, "height": 720, "lastModified": "1540947683670041", "quality": "hd720", "fps": 25, "qualityLabel": "720p", "projectionType": "RECTANGULAR", "audioQuality": "AUDIO_QUALITY_MEDIUM", "approxDurationMs": "231526", "audioSampleRate": "44100", "audioChannels": 2, "signatureCipher": "s=NOqNOqAOq0QJ8wRgIhAPExkdMZDe9ZTraakz6Bwe6dfJg_zlcsKzb8DUjAkj9vAiEA5t13JtRk6h4uCqpDLFVGDNS4Y9coFH0jmN_RA4w2OF4%3D4%3D&sp=sig&url=https://r3---sn-gvnuxaxjvh-v8cz.googlevideo.com/videoplayback%3Fexpire%3D1608470232%26ei%3DePreX--ZJp7k7QSX7ZeQAg%26ip%3D45.130.147.179%26id%3Do-ALD2y-ml9SgSmfTWLsMgAsrJhxXeyifGx11q-XbNj8hG%26itag%3D22%26source%3Dyoutube%26requiressl%3Dyes%26mh%3D6M%26mm%3D31%252C29%26mn%3Dsn-gvnuxaxjvh-v8cz%252Csn-bvvbax-v8ce%26ms%3Dau%252Crdu%26mv%3Dm%26mvi%3D3%26pl%3D25%26nh%3D%252CEAQ%26initcwndbps%3D808750%26vprv%3D1%26mime%3Dvideo%252Fmp4%26ns%3Dd5m8cRSyarA_Cm7w02hO920F%26ratebypass%3Dyes%26dur%3D231.526%26lmt%3D1540947683670041%26mt%3D1608448358%26fvip%3D3%26c%3DTVHTML5%26txp%3D5531432%26n%3DrfCdri435GWZqxDhX8%26sparams%3Dexpire%252Cei%252Cip%252Cid%252Citag%252Csource%252Crequiressl%252Cvprv%252Cmime%252Cns%252Cratebypass%252Cdur%252Clmt%26lsparams%3Dmh%252Cmm%252Cmn%252Cms%252Cmv%252Cmvi%252Cpl%252Cnh%252Cinitcwndbps%26lsig%3DAG3C_xAwRAIgUNHvqa8A_-zAld5Nt1NMtAl6fM009_ntzDNXq-jrDpgCIBaLfgWsnub1Fxac0oq6m5a-2Ilw8I3_58MBvOcFa2xB" }