Couple of things to note:
First, the number of lines displayed depend upon the application, there is not standard for the actual number of lines displayed. You can get the specification details here: SRT Specifications
Second, parsing the line break depends on the application. Some applications want CFLR (dos style, carriage return + line feed) and some only LF (unix style Line feed only). You need to see what VLC needs, try changing the line break to CRLF and LF and see if that fixes your issue. I'm not sure of TextEdit support both styles of line break, VIM or GVIM does.