[Vm-dev] Official VM missing MPEGPlugin

[Eliot Miranda]

On Sat, Jan 15, 2011 at 9:14 AM, David T. Lewis <lewis at mail.msen.com> wrote:

>
> On Fri, Jan 14, 2011 at 11:59:47AM -0500, Matthew Fulmer wrote:
> >
> > Cog VM includes the MPEGPlugin, but the interpreter VM from
> > http://ftp.squeak.org/4.1/
> > does not. It's needed by Cobalt.
>
> Well I'm stumped. The plugin exists and is installed in the normal
> place. But it is not being loaded when called from #primFileValidMPEG:.
> There are no errors (e.g. unresolved symbols etc) and no problems
> compiling, we are just not finding the plugin at runtime.
>
> I'm sure I'm missing something obvious, but I can't spot it.
>

I suspect it's not obvious and I'd be willing to bet there /is/ an undefined
symbol in the plugin.  It won't show on the compiler command line unless you
compile carefully, since the compiler does allow undefined symbols, a
side-efeft of the default global namespace.  If the program into which a
shared library is loaded has already loaded some other shared library that
defines undefined in that first shared library the first shared library will
get its definition from the other.  So remake the plugin, capturing the link
step, and then manually repeat the link step supplying
"-Wl,--warn-unresolved-symbols -Wl,--no-allow-shlib-undefined" and hopefully
you'll be informed of the undefined symbols.

HTH
Eliot


> > To test:
> >
> > - Load up Movies-Kernel and Movies-Player from
> >   http://www.squeaksource.com/MultiMedia.html
> >   (aside: anyone know of a more official location for multimedia
> >   stuff?)
> > - Get out an MPEGPlayerMorph (World > objects > Multimedia >
> >   MPEGPlayer)
> > - press the load button and find your favorite mpeg file. I
> >   threw up the one we ship with cobalt in case you don't have
> >   one on hand (3.1 MB):
> >   http://cobalt.cs.duke.edu/pub/alien.mpeg
>
> FYI, access is denied to this file:
>
>  Forbidden
>
>  You don't have permission to access /pub/alien.mpeg on this server.
>  Apache/2.2.14 (Ubuntu) Server at cobalt.cs.duke.edu Port 80
>
> > - official VM will get a primitive failure at this point
> > - Cog will show the first frame of the video and you can watch
> >   it by pressing play
> >
> > --
> > Matthew Fulmer (a.k.a. Tapple)
>
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