NooB Q. - controlling a remote gstreamer app

Sat Feb 25 09:08:32 PST 2012

The protocol to do these kinda things would be SIP I think.
There's a book by Morgan Kaufmann called "Internet Multimedia
Communications Using SIP".

Its about GStreamer though, but SIP (as the title suggests). Maybe give it
a try. Also check gstreamer-java if that is more your thing ...

Good luck!

On Sat, Feb 25, 2012 at 5:31 PM, Sean McNamara <smcnam at gmail.com> wrote:

> Hi,
>
> On Sat, Feb 25, 2012 at 12:26 AM,  <gstream at ccc2.com> wrote:
> > Hi All,
> >
> > I am not a C. programmer at all. I have followed the tutorials and
> > examples and have a working videomixer2 application. Can you give advice
> > as to how I can interact with this app on a remote linux box. I assume it
> > is with sockets etc (telnet?). Any advice and some examples would be
> > great.
>
> First, this is not a gstreamer question. Just because you're *using*
> gstreamer doesn't mean that the nature of your question is at all
> related to gstreamer. This is a general applications programming
> question, because the nature of your question is *networking*, not
> *the gstreamer API*. I'm replying as a courtesy, but please keep the
> SNR of this list high by not posting further non-gstreamer questions
> to this list.
>
> This is where having some software engineering knowledge would help you.
>
> First of all, if you're doing this over the public internet, you need
> an authentication mechanism for your network service. And since
> authentication over plain text is basically the same as having no
> authentication, you're going to need encryption, message
> authentication, and a bunch of other things. Rather than trying to
> design something like this from scratch, I'd suggest to just use an
> existing solution that is secure enough that most people trust it.
>
> Basically, don't try to cheat by doing something simple/easy like
> telnet, unless this service is ONLY going to listen on a LAN IP
> address and you trust every computer that connects to that LAN.
> Assuming you're good with using existing GNOME technology, you might
> look at using libsoup as an HTTPS ("S" for "SSLv3" / "TLS") server.
> Once you have an authenticated SSL or TLS tunnel with the client, you
> can pretty much code up an arbitrary request/response protocol between
> the client and server.
>
> It'd go something like this, starting at OSI layer 5 (Session):
>
> 0. Client establishes a TCP socket connection on port 443 (or
> whatever) with server. (Layer 5)
> 1. Client sends an SSL HelloRequest to server. (Layer 6)
> 2. Client and server complete an SSL handshake to establish a secure
> connection. (Layer 6)
> 3. Client pushes across an HTTP Request (tunneled through SSL) with a
> body containing the authentication data. Don't use URL params. For a
> low-risk system like this with no concept of user accounts, just a 20+
> character password could be sufficient.
> 4. If the client sent the right password, the server sends an HTTP
> Response back with a body containing something like "OK". If the
> client sent the wrong password, terminate the TCP connection and don't
> respond to that host until they initiate a new connection.
> 5. Client pushes across another HTTP Request, with a body containing
> plain text that the server will parse to figure out what property to
> set on the element, and what value. You can do something as simple as
> name=value.
> 6. Server will call g_object_set() on the appropriate gstreamer
> element, in order to set the property at runtime.
> 7. Here, you can optionally keep the channel open for re-use (to avoid
> having to start over from step 1 if you want to set another property).
> Or you can kill it on either side if you're done.
>
> If you use libsoup on the server, you can do this without starting
> another thread, because libsoup has async methods that call a callback
> that's tied into the GLib main loop. Only using one thread doesn't
> scale extremely well to a large number of clients, but this sounds
> like a simple job, so a simple solution will do.
>
> If the server is behind a NAT (i.e. it can listen on an IP that will
> let it connect to other LAN computers but not let the public internet
> connect to it), you CAN use the above method (extra security never
> hurts), but you could skip the SSL if you want, if you are sure that
> no unauthorized persons can connect to your LAN (an unsecured wifi
> network would be an example of an *insecure* LAN).
>
> If you have no idea where to start, start here:
> http://developer.gnome.org/libsoup/stable/libsoup-server-howto.html .
> I would recommend learning the APIs and their semantics, rather than
> just blindly copying and pasting from examples.
>
> BTW, you don't *have* to use C to write gstreamer apps. Since you
> indicated you don't really know how to program in C, I would suggest
> that you don't, unless you have some specific reason to. I would
> suggest Python or Vala  for a task such as this one. You get soup and
> gstreamer bindings "for free" in those languages, and the syntax is a
> lot friendlier.
>
>
> >
> > As an example I am using
> >  g_object_set (G_OBJECT (decoder2), "max-size-time", (guint64)300000000,
> > NULL);
>
> ...So you already know the only gstreamer-relevant topic in your
> question, and this entire post has been off-topic for this list. Just
> FYI.
>
> >
> > and would like to update this function with a new time manually.
> >
> > I have found some basic telnet socket examples but have no clue on how to
> > mix both applications together so I can control gst.
> >
> > thx
> > Art.
> >
> > _______________________________________________
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> > gstreamer-devel at lists.freedesktop.org
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>

-- 
*Michael Niemand*
*
*
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