python bindings for gstreamer: how to import typelib

Question

I was building gstreamer latest version on my raspberry pi. I wanted to have python bindings, hence I installed gobject-introspection-1.0 and pygobject-3.18.2 before compiling the gstreamer and its plugins.

At the end of the build of gstreamer and all of its plugins, I see these files:

pi@raspberrypi:~/kurento $ ls -ltr /usr/local/lib/girepository-1.0
total 580
-rw-r--r-- 1 root staff 214076 Mar 28 19:28 Gst-1.5.typelib
-rw-r--r-- 1 root staff  43712 Mar 28 19:28 GstBase-1.5.typelib
-rw-r--r-- 1 root staff   6500 Mar 28 19:28 GstController-1.5.typelib
-rw-r--r-- 1 root staff   6272 Mar 28 19:28 GstNet-1.5.typelib
-rw-r--r-- 1 root staff  13116 Mar 28 19:29 GstCheck-1.5.typelib
-rw-r--r-- 1 root staff  14460 Mar 28 20:23 GstTag-1.5.typelib
-rw-r--r-- 1 root staff   2508 Mar 28 20:23 GstFft-1.5.typelib
-rw-r--r-- 1 root staff  27460 Mar 28 20:23 GstRtp-1.5.typelib
-rw-r--r-- 1 root staff  24160 Mar 28 20:23 GstSdp-1.5.typelib
-rw-r--r-- 1 root staff  32856 Mar 28 20:23 GstRtsp-1.5.typelib
-rw-r--r-- 1 root staff  75268 Mar 28 20:23 GstVideo-1.5.typelib
-rw-r--r-- 1 root staff  46800 Mar 28 20:24 GstAudio-1.5.typelib
-rw-r--r-- 1 root staff  25764 Mar 28 20:24 GstPbutils-1.5.typelib
-rw-r--r-- 1 root staff   5732 Mar 28 20:24 GstApp-1.5.typelib
-rw-r--r-- 1 root staff   1876 Mar 28 20:24 GstAllocators-1.5.typelib
-rw-r--r-- 1 root staff  17736 Mar 28 22:37 Nice-0.1.typelib

Then I compiled gst-python-1.7.1 and then I see the following at appropriate location:

pi@raspberrypi:~/kurento $ ls -l /usr/local/lib/python2.7/site-packages/gi/overrides/
total 640
-rw-r--r-- 1 root staff 15002 Mar 28 18:11 Gdk.py
-rw-r--r-- 1 root staff 14996 Mar 28 18:11 Gdk.pyc
-rw-r--r-- 1 root staff 14996 Mar 28 18:11 Gdk.pyo
-rwxr-xr-x 1 root staff  1141 Mar 29 22:19 _gi_gst.la
-rwxr-xr-x 1 root staff 56124 Mar 29 22:19 _gi_gst.so
-rw-r--r-- 1 root staff  2240 Mar 28 18:11 GIMarshallingTests.py
-rw-r--r-- 1 root staff  2428 Mar 28 18:11 GIMarshallingTests.pyc
-rw-r--r-- 1 root staff  2428 Mar 28 18:11 GIMarshallingTests.pyo
-rw-r--r-- 1 root staff  8147 Mar 28 18:11 Gio.py
-rw-r--r-- 1 root staff  8176 Mar 28 18:11 Gio.pyc
-rw-r--r-- 1 root staff  8075 Mar 28 18:11 Gio.pyo
-rw-r--r-- 1 root staff 33233 Mar 28 18:11 GLib.py
-rw-r--r-- 1 root staff 31701 Mar 28 18:11 GLib.pyc
-rw-r--r-- 1 root staff 31656 Mar 28 18:11 GLib.pyo
-rw-r--r-- 1 root staff 26255 Mar 28 18:11 GObject.py
-rw-r--r-- 1 root staff 23401 Mar 28 18:11 GObject.pyc
-rw-r--r-- 1 root staff 23401 Mar 28 18:11 GObject.pyo
-rw-r--r-- 1 root staff  2785 Mar 29 22:19 GstPbutils.py
-rw-r--r-- 1 root staff  2584 Mar 29 22:19 GstPbutils.pyc
-rw-r--r-- 1 root staff  2584 Mar 29 22:19 GstPbutils.pyo
-rw-r--r-- 1 root staff 11570 Mar 29 22:19 Gst.py
-rw-r--r-- 1 root staff 16602 Mar 29 22:19 Gst.pyc
-rw-r--r-- 1 root staff 16602 Mar 29 22:19 Gst.pyo
-rw-r--r-- 1 root staff 56202 Mar 28 18:11 Gtk.py
-rw-r--r-- 1 root staff 64602 Mar 28 18:11 Gtk.pyc
-rw-r--r-- 1 root staff 64602 Mar 28 18:11 Gtk.pyo
-rw-r--r-- 1 root staff 12820 Mar 28 18:11 __init__.py
-rw-r--r-- 1 root staff 13128 Mar 28 18:11 __init__.pyc
-rw-r--r-- 1 root staff 13070 Mar 28 18:11 __init__.pyo
-rw-r--r-- 1 root staff  1705 Mar 28 18:11 keysyms.py
-rw-r--r-- 1 root staff  1137 Mar 28 18:11 keysyms.pyc
-rw-r--r-- 1 root staff  1137 Mar 28 18:11 keysyms.pyo
-rw-r--r-- 1 root staff  1679 Mar 28 18:11 Pango.py
-rw-r--r-- 1 root staff  1727 Mar 28 18:11 Pango.pyc
-rw-r--r-- 1 root staff  1727 Mar 28 18:11 Pango.pyo

With this setup, I expect to see Gst module being loaded from gi repository.

>>> sys.path
['/usr/local/lib/python2.7/site-packages', '', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-arm-linux-gnueabihf', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/pymodules/python2.7']
>>> import gi
>>> from gi.repository import Gst
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: cannot import name Gst
>>> gi.require_version('Gst','1.5')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/site-packages/gi/__init__.py", line 102, in require_version
    raise ValueError('Namespace %s not available' % namespace)
ValueError: Namespace Gst not available
>>> 

But this is not happening. Please, your help is needed to import the Gst modules into python. Has anyone come across similar situation?

Thanks!

Answer 1

GObject instrospection need type descriptions located at /usr/lib/girepository-1.0

In my case I have:

/usr/lib/girepository-1.0$ ls Gst*1.5*

Gst-1.5.typelib            GstFft-1.5.typelib        GstRtp-1.5.typelib
GstAllocators-1.5.typelib  GstGL-1.5.typelib         GstRtsp-1.5.typelib
GstApp-1.5.typelib         GstInsertBin-1.5.typelib  GstSdp-1.5.typelib
GstAudio-1.5.typelib       GstMpegts-1.5.typelib     GstTag-1.5.typelib
GstBase-1.5.typelib        GstNet-1.5.typelib        GstVideo-1.5.typelib
GstCheck-1.5.typelib       GstPbutils-1.5.typelib
GstController-1.5.typelib  GstPlayer-1.5.typelib

Try installing typelib files there.

I don't have any Gst*.py files installed, with the types description is enough.

Edit

Defining GI_TYPELIB_PATH pointing it to the directory containing the typelib files, in your case /usr/local/lib/girepository-1.5, also solves the problem.