Itatsumaki has asked for the wisdom of the Perl Monks concerning the following question:

Perhaps I am fundamentally misunderstanding my formats and protocols, but I was surprised to find that I couldn't easily automate the download of streaming media via LWP.

I have a fairly large set (a couple of hundred) of streaming video/audio clips that I wanted to download regularly for a client across an intranet as a backup procedure, and I just can't seem to make it work. The server is an mms server, which is a micro$oft product, and somehow IE knows well enough to hand it off to Media-Player, so perhaps I could emulate that and just save the streamed output?

It was surprisingly hard to find a web-based MMS server to show a script on, but here is one in Japan. It might be a bit slow, given the distance but the principle should be the same. The file plays okay in media-player, but I can't grab it with LWP using this code:

use LWP::UserAgent;
my $agent = LWP::UserAgent->new();
my $response = $agent->get('mms://wms01.aii.co.jp/hotshot/yoshioka.wmv
+');
open(OUT, '>test1.wmv');
binmode OUT;
print OUT $$response{content};

[download]

Any ideas, advice, or suggestions much appreciated. Especially if I'm under some fundamental misconception that it *is* possible to grab streaming media files via PERL! :) I should mention: it fails with both LWP::UserAgent and LWP::Simple, and it seems to just not return any content. I suppose it isn't returning an HTTP-header, which must be the start of my problems....

Tats

Replies are listed 'Best First'.
Re: Download Streaming Media?
by iburrell (Chaplain) on Apr 18, 2003 at 20:56 UTC
    MMS uses a proprietary protocol. Microsoft has not released a specification for it. The SDP project (http://sdp.ppona.com/) is working on reverse engineering the protocol. Nobody has implemented a Perl interface.

    Do you need to the download the files through the streaming interface? Are there files on disk you can copy? You could copy the files using a standard mechanisms, like SMB, NFS, FTP, HTTP, SSH, etc.

[reply]

      Ahh, that answers it then. I'll check on SDP, but I'll just have to set up an FTP server then. I wanted to avoid that since the mms was already up-and-running. If MS has released an API to it, I suppose someone could implement a wrapper to it but... why go to that much trouble to replace FTP? :)

      Thanks for your help,
      Tats
[reply]
        The idea behind it all is "content control". That's why it is not to be expected that Microsft will ever release the specification for MMS.

        BTW the home page for the SDP project is here.

        If you're looking for a more open alternative to MMS, you can use the Shoutcast streaming protocol, which is more openly based on HTTP. Apache can serve as such a server, or something very similar, with mod_perl and the module Apache::MP3. That way, you get the best of both worlds.

[reply]
Re: Download Streaming Media?
by Limbic~Region (Chancellor) on Apr 18, 2003 at 21:25 UTC
    Itatsumaki,
    There is a commercial product here that does what you are looking for. The cost looks fairly inexpensive.

    You can also do a search on ASFRecorder. Best as I can tell, a guy reverse engineered how the streaming media worked and provided open source on how to do it. The author remained anonymous, and got hired by the very company he - well, you get the picture. It provides a batch operation. The two most relavent links are here:

  • Down Load
  • Sourceforge

    Of course this is written in C and would have to be converted to Perl unless you just want to use one of these tools.

    I in no way endorse the use of the this product to make illegal copies of media that is not owned or licensed.

    Cheers - L~R

[reply]
      Thanks L~R
[reply]
Re: Download Streaming Media?
by isotope (Deacon) on Apr 18, 2003 at 21:52 UTC 
    ls -la /usr/lib/perl5/site_perl/5.6.1/LWP/Protocol
total 96
drwxr-xr-x    2 root     root         4096 Mar 10 20:18 .
drwxr-xr-x    4 root     root         4096 Mar 10 20:18 ..
-r--r--r--    1 root     root         1279 Nov 19  1998 data.pm
-r--r--r--    1 root     root         3827 Aug  6  2001 file.pm
-r--r--r--    1 root     root        17014 Oct 26  2001 ftp.pm
-r--r--r--    1 root     root         1823 Apr  9  2001 GHTTP.pm
-r--r--r--    1 root     root         5783 Nov 19  1998 gopher.pm
-r--r--r--    1 root     root         8459 Oct 26  2001 http10.pm
-r--r--r--    1 root     root        10566 Sep 20  2002 http.pm
-r--r--r--    1 root     root         1822 Oct 26  2001 https10.pm
-r--r--r--    1 root     root         1236 Nov 16  2001 https.pm
-r--r--r--    1 root     root         4190 Mar 19  1999 mailto.pm
-r--r--r--    1 root     root         3749 Nov 19  1998 nntp.pm
-r--r--r--    1 root     root          630 May  5  2001 nogo.pm

    [download]
    LWP only supports a certain list of protocols. mms:// is not one of them. One could certainly learn about the protocol and write mms.pm for LWP, but it appears that no one has done so at this time. If you follow this example, the problem should become more clear:

             # Create a user agent object
         use LWP::UserAgent;
         $ua = LWP::UserAgent->new;
         $ua->agent("MyApp/0.1 ");

         # Create a request
         my $req = HTTP::Request->new(POST => 'http://www.perl.com/cgi
+-bin/BugGl
impse');
         $req->content_type('application/x-www-form-urlencoded');
         $req->content('match=www&errors=0');

         # Pass request to the user agent and get a response back
         my $res = $ua->request($req);

         # Check the outcome of the response
         if ($res->is_success) {
             print $res->content;
         } else {
             print "Bad luck this time\n";
         }

    [download]
    Note the creation of an HTTP::Request object. --isotope
    http://www.skylab.org/~isotope/
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