Export movie/image asset file into the disk

This is taken from the stack overflow and slightly modified 

- (BOOL) exportDataToURL: (NSString*) filePath error: (NSError**) error andAsset:(ALAsset*)asset

{

    NSError **errorInternal = nil;

    [[NSFileManager defaultManager] createFileAtPath:filePath contents:nil attributes:nil];

    NSFileHandle *handle = [NSFileHandle fileHandleForWritingAtPath:filePath];

    if (!handle) {

        return NO;

    }

    

    static const NSUInteger BufferSize = 1024*1024;

    ALAssetRepresentation *rep = [asset defaultRepresentation];

    uint8_t *buffer = calloc(BufferSize, sizeof(*buffer));

    NSUInteger offset = 0, bytesRead = 0;

    

    do {

        @try {

            bytesRead = [rep getBytes:buffer fromOffset:offset length:BufferSize error:error];

            [handle writeData:[NSData dataWithBytesNoCopy:buffer length:bytesRead freeWhenDone:NO]];

            offset += bytesRead;

        } @catch (NSException *exception) {

            free(buffer);

            

            return NO;

        }

    } while (bytesRead > 0);

    

    free(buffer);

    return YES;

}