I'm trying to extract subtitles from unencrypted DVDs with a program, so I can save them seperately. I know there are programs that do that (I found this page for example: http://www.bunkus.org/dvdripping4linux/en/separate/subtitles.html), but I would like to be able to do it with a library call or something like that (do libdvdread or libdvdnav support this), preferably using ruby.
A:
I don't know of any library, which would be able to do this.
In ruby you can call programs. For example to get a directory listing you can do
files= `ls "#{dir}"`.to_a
The backtick variant gives you stdout of the calle program.
To know wheter a file exists
system("ls \"#{file}\"")
The system variant tells you whether the return value of the called program was 0.
Using this two methods, you can do almost anything with noninteracitve programs. The programs described in http://www.bunkus.org/dvdripping4linux/en/separate/subtitles.html seme to be suitable for this kind of control.
Be carefull with escaping arguments you give to external programs. If an argumend is "; rm -rf *; ls ". undesirable things may happen.
johannes
2009-12-13 21:18:06