Dax equavalent

I am attempting a more complex one this time.. in similiar lines. Any pointers ?

SELECT convert(decimal(20,4), Interval_buffering_time*100/(Interval_buffering_time + Interval_playing_time)) as buffering_ratio

FROM (

  SELECT

    ROUND((SUM(case when a.buffering_time_ms >30*60*1000  then 30*60*1000 else a.buffering_time_ms - isnull(b.prior_buffering_time_ms,0) end  )/60000),2) AS Interval_buffering_time,

    ROUND((SUM(a.buffering_time_ms)/60000),2) AS life_buff_time ,

    ROUND((SUM(a.playing_time_ms - isnull(b.prior_playing_time_ms,0) )/60000),2) AS Interval_playing_time

    FROM (

          SELECT playing_time_ms,

                buffering_time_ms,

                conviva_session_id,

                startup_time_ms,

                start_time_unix_time,

                ssd

                FROM conviva_qoe_data WHERE ssd = '2022/10/08' AND startup_time_ms!=-1) a

                LEFT outer JOIN (

                  SELECT r.conviva_session_id AS prior_session_id,

                         r.buffering_time_ms AS prior_buffering_time_ms,

                         r.playing_time_ms AS prior_playing_time_ms,

                         r.startup_time_ms as p_startuptime,

                         r.start_time_unix_time as p_starttime

                  FROM conviva_qoe_Data r

                    WHERE r.ssd = '2022/10/09' ) b

                    ON (a.conviva_session_id = b.prior_session_id and   a.start_time_unix_time =b.p_starttime)

     where a.playing_time_ms>0

   ) Tmp