using System;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var subtitles = "[{ \"frameRate\" : \"25\", \"dropFrame\": false}, { \"frameRate\" : \"25\", \"dropFrame\": false}, { \"frameRate\" : \"25\", \"dropFrame\": false}, { \"frameRate\" : \"25\", \"dropFrame\": false}]";

        JArray subTitleArray = JArray.Parse(subtitles);

​

        //This will return true if `frameRate` of each element is 25

        var validFrameRate = subTitleArray.All(x => x.Value<string>("frameRate") == "25"); 

        Console.WriteLine(validFrameRate ? "Same frameRate in all elements" : "Different FrameRate in all elements");

    }

}