Regex :
/^\s*\d+\s*$(?:\r?\n?)+^\s*([\d:,.]+)\s*-->\s*([\d:,.]+)\s*$(?:\r?\n?)+((?:.(?:\r?\n?)?)?)(?:\r\n|\r|\n|$)/gm;
Test String : 1 00:00:02,070 --> 00:00:8,572 (<i> explosion and number of members</i> ) (<i> inaudible radio chatter</i> )