[gst-devel] [Announce] gst-gengui 0.1 : live interaction with pipelines

[Sean McNamara]

Hi,

On Wed, May 20, 2009 at 2:54 PM, Florent <fthiery at gmail.com> wrote:
> Hello,
>
> I would like to announce gst-gengui 0.1 to the gstreamer community.

Cool!

>
> This small project's goal is to let gstreamer developers more easily
> test their plugins and live-manipulate gstreamer pipelines and
> plugins. In other terms, it is comprised of a gst introspector module
> (which looks up the contents of a pipeline either specified on
> command-line in a similar syntax as gst-launch) and a sample GTK
> application which builds GTK value changer widgets.

Does the project also have (or plan to have) functionality similar to
the gst-editor program (which appears to be unmaintained, or only
minimally so)? For instance, visually constructing a pipeline by
dragging lines from source to sink, then get an output gst-launch
pipeline description.

>
> You can find the code and screenshot here: http://code.google.com/p/gst-gengui/
> 0.1 initial release: http://gst-gengui.googlecode.com/files/gstgengui-0.1.tar.gz

I grabbed it from googlecode SVN...

> It has a dependency on http://code.google.com/p/gstmanager/

gstmanager has a "nice" build system, if you can call it that -- at
least it installed into the right directory.

>
> Please let me know if you're running into issues when using it...

The INSTALL file is a little outdated (even in SVN) as it doesn't
mention setup.sh. Besides that, setup.sh is extremely simplistic and
assumes several things which may or may not be correct:

1) That we want it installed in /usr/local instead of just /usr
2) That we want it installed in 'lib' instead of 'lib64'
3) That we're using Python 2.5 instead of some other Python version.

These things aren't "configurable" except for modifying the script.

In the case of gstmanager, its setup.py script was able to correctly
do 1) and 3) for me; that is, it installed it into
/usr/lib/python2.6/site-packages/gstmanager. In this case it seems to
work fine, even though I'm using a 64-bit Python interpreter on a
64-bit kernel. If gstmanager's setup.py is indeed detecting the
'python2.6' bit instead of just assuming a certain Python version, I
might recommend you use that script as your install script instead.

I'm not a Python expert, though -- in fact I know very little about it
-- all I can suggest is that you can probably auto-detect at least the
2) and 3) variables above, and personally I'd prefer a default of
/usr/ instead of /usr/local/ for 1). But it should at least be
configurable with a minimal command line interface.


As for the functionality of the program itself, it's rather cool. I
played around with it briefly by doing

gst-gengui audiotestsrc ! volume volume=0.3 ! autoaudiosink

and I could change the volume using a GTK slider... and the volume was
actually updated in realtime! :)

However, a few issues immediately appear with this early release
(understandable, just pointing them out):

1) The default GUI looks like this: http://tiyukquellmalz.org/gst-gengui.png
Is the top part of the window (empty) supposed to have something in
it? By dragging the horizontal divider to the top of the screen I was
able to use more of the window for viewing the rendered components.
2) When changing the pipeline description in the text field, the list
of element properties isn't updated, when you click Refresh, if you
insert an erroneous pipeline. And the GUI doesn't indicate a problem.
For instance, I tried to add a 'pitch' element without realizing that,
for some reason, my distro doesn't ship this element in
gst-plugins-bad :) So I almost reported that this feature doesn't work
at all, until I tried adding an audioconvert instead -- THAT worked.
So the "normal" path (changing the pipeline, hitting Refresh, where
the pipeline is valid) is fine, but the error path is a bit cryptic.

This is a cool developer tool... I'll keep my eye on it :)

Regards,

Sean


>
> Cheers,
>
> FLo
>
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