FourCharCode to String

FourCCString.m

// https://developer.apple.com/documentation/avfoundation/avassettrack/1386694-formatdescriptions?language=objc
static NSString * FourCCString(FourCharCode code) {
    NSString *result = [NSString stringWithFormat:@"%c%c%c%c",
                        (code >> 24) & 0xff,
                        (code >> 16) & 0xff,
                        (code >> 8) & 0xff,
                        code & 0xff];
    NSCharacterSet *characterSet = [NSCharacterSet whitespaceCharacterSet];
    return [result stringByTrimmingCharactersInSet:characterSet];
}