<?php
$array=array();
    $array["720p"] = "deger"==true;
    $array["subtitle"] = "varmi"==true;
    $array["tr"] = "bilmiyorum"==true;
    
    
    echo "Json Hali: ".json_encode($array);
    echo "<br/>";
    var_dump( json_decode(json_encode($array)) );

Json Hali: {"720p":true,"subtitle":true,"tr":true}
object(stdClass)#1 (3) { ["720p"]=> bool(true) ["subtitle"]=> bool(true) ["tr"]=> bool(true) }