internal static MediaType FromString(string s)
{
if(String.Equals(s, AUDIO.stringValue, StringComparison.InvariantCultureIgnoreCase))
return AUDIO;
else if(String.Equals(s, VIDEO.stringValue, StringComparison.InvariantCultureIgnoreCase))
return VIDEO;
else if(String.Equals(s, SCREEN.stringValue, StringComparison.InvariantCultureIgnoreCase))
return SCREEN;
else
return null;
}