Adding GStreamer plugins

[Kirill Kirichenko]

Hi Michael.
See my comments inline.

On 24.03.2014 04:31, Michael Berry wrote:
> I'm now a bit further along with this, though struggling to get the
> matroska plugin to compile (getting a bunch of unresolved external symbol
> errors for functions it uses in glib - not entirely sure why at the moment,
> as I said C is not my strong point.) I've also noticed the plugins
> currently bundled have quite a few changes to the gstreamer version, and I
> can't quite work out the logic behind why things have been changed the way
> they have - so even after the compilation issue is resolved I'm now less
> confident that it will just drop in and work! Again, if someone
> knowledgeable in this area that's lurking in the shadows could shed any
> light on any of this, it would be hugely appreciated.
We did some changes in existing GStreamer code because it had errors and 
because we needed to expand some functionality. The changes are not very 
extensive.

> However, putting the current problems aside for a bit, the snags I hit up
> until this point could I think be relatively easily addressed in the
> documentation. With that in mind could I suggest a few additional points
> for the wiki? These may be obvious to the majority reading here, but as
> someone completely new to building JFX they had me stumped for a while!
I can give you some directions. There is no wiki. I'd appreciate if you 
created one.

>   - It turns out that the Gstreamer stuff doesn't compile at all by default,
> which is why I wasn't seeing any changes on the native level. To ensure
> GStreamer is actually compiled, you need to copy the
> gradle.properties.template file to gradle.properties, and uncomment the
> "#COMPILE_MEDIA = true" line. (A similar scenario would appear to exist for
> any webkit alterations as per the line above.)
You don't need to comment/uncomment anything. Just add 
-PCOMPILE_MEDIA=true to the gradle command line. You can however change 
the properties file too.

>   - As well as the requirements listed, I needed the Windows SDK (
> http://www.microsoft.com/en-gb/download/details.aspx?id=8279) installed for
> GStreamer to compile successfully under Windows (7) - without it cygpath
> just threw a rather confusing error.
You need windows 7.1a SDK and speaking precisely you need only samples 
from it because samples have BaseClasses at 
Samples/multimedia/directshow/baseclasses. BaseClasses are used for 
Oracle direchshowwrapper plugin.

>   - The developer workflow page (
> https://wiki.openjdk.java.net/display/OpenJFX/Developer+Work+Flow) refers
> to  "-Djavafx.ext.dirs" - I think this should be "-Djava.ext.dirs" instead?
What are you gonna use it for ?

> I'm happy to make the above changes myself but unsure of if / where you can
> sign up for an account, so I'm just throwing them here for now - if anyone
> could point me to the right place then that'd be great!
Steve. Can you give an advice ?

> If I do ever manage to get this working (ha-ha) I'd also like to throw up a
> wiki page just detailing how to grab a gstreamer plugin and make the
> necessary changes to it to compile it into openjfx as a stop gap to then
> perhaps working on one or both of the above JIRA issues and seeing where I
> get - does this sound reasonable?
It does.


>>> On Mar 22, 2014, at 9:26 PM, Michael Berry <berry120 at gmail.com> wrote:
>>>> However, I'm not sure if I'm going about including the matroska plugin
>>> in
>>>> the right way - I've currently done the following:
>>>>
>>>> - Downloaded the latest version of the plugins from here (
>>>> http://gstreamer.freedesktop.org/src/gst-plugins-good/), then added the
>>>> matroska one to the modules/media/src/main/native/gstreamer/plugins/
>>>> folder, as well as the
>>>>
>>> modules/media/src/main/native/gstreamer/gstreamer-lite/gst-plugins-good/gst/
>>>> folder (I'm unsure of this - should I add it to both these folders?).
Well you see. If you download the latest matroska plugin it potentially 
can have dependencies on the latest GStreamer platform. We don't 
have/use the latest gstreamer. The version we use is 0.10.35. And the 
latest available is 1.x. They are incompatible in some methods.

>>>> - Added all the C files from the first folder mentioned above to the
>>>> plugins.vcxproj file
>>>>
>>>> - Added the relevant files and directory to Makefile.gstplugins
>>>>
>>>> - Called the additional relevant plugin_init() function in
>>>> gstplugins-lite.c
There is one more thing you need to do here for Windows only apart from 
running gradle with -PCOMPILE_MEDIA=true. Windows build system has files 
that export symbols
1) from glib-lite.dll 
${jfxroot}/rt/modules/media/src/main/native/gstreamer/3rd_party/glib/glib-2.28.8/build/win32/vs100/{glib-lite.def|glib-liteD.def} 

Here the version with "D" is used for debug build and may contain more 
symbols for export.
2) from gstreamer-lite.dll 
${jfxroot}/rt/modules/media/src/main/native/gstreamer/projects/win/gstreamer-lite.def 
- used for both Release and Debug.

If your plugin uses some methods of gstreamer/glib libraries not 
mentioned in the files you should add the methods to the files. Syntax 
is pretty simple. If you don't add depending methods to these files you 
will get linker errors. C/C++ compiler will not generate errors.

Actually I think the best way to start developing/improving the Media 
component is to upgrade GStreamer to 1.x from 0.10.35. It would be a 
very good starting point and you would get less or no problems using the 
latest available plugins. If someone wanna take over this I can explain 
in details how to do it.

K