How to freeze app using opencv without pygobject/gi? Why is pygobject / gi imported?

[ben-xD]

Background

My app uses gstreamer and OpenCV and runs fine before pyinstaller. I don't use pygobject, only opencv needs gstreamer.

Problem

After freezing with pyinstaller, my executable crashes with CRITICAL **: 22:28:22.611: pygobject initialization failed: could not import gobject (error was: ModuleNotFoundError("No module named 'gi'"))

I can see a lot of import gi in pyinstaller hooks. None in my code. I'm also finding it hard to debug which are hooks being run.

Does anyone have advice about this? Thanks in advance

Current attempt

I have tried using excludes and overriding some hooks:

a = Analysis(
    ['main.py'],
    pathex=['.'],
    binaries=[],
    runtime_hooks=[],
    excludes=["pygobject", "gi", "gobject", "gi.repository", "gi._gi"],
    datas=[], 
    hookspath=["hooks"],
    noarchive=False,
)

Where I have ./hooks folder containing files like hook-gi.py, with:

# Empty hook to prevent collecting unnecessary GObject Introspection modules
hiddenimports = []
excludedimports = ['gi.repository']

My packages

$ py -3.13 -m pip freeze
colorama==0.4.6
numpy==2.2.6
packaging==25.0
pefile==2023.2.7
pyinstaller==6.13.0
pyinstaller-hooks-contrib==2025.4
pywin32-ctypes==0.2.3
setuptools==80.7.1
types-pyinstaller==6.13.0.20250417

[rokm]

Does the executable crash when executing your program code or while it is still executing our run-time hooks? If you change debug=False under EXE in the .spec and rebuild, what does the full executable's output up to the crash look like?

If the crash happens in your program, can you instrument it with additional print statements to see what package is being imported when it crashes? Alternatively, you can also change:

exe = EXE(
    pyz,
    a.scripts,
    [],
...

into

exe = EXE(
    pyz,
    a.scripts,
    [('v', None, 'OPTION')],
...

and rebuild. This will dump information about all imports that happen, so you can see what import chain led to the crash.

My guess would be that you have some component that actually depends on gi and you are causing it to crash because you are explicitly excluding it. But on the other hand, I would also expect PyGObject to appear in your pip freeze output...

[rokm]

Come to think of it, do you perhaps have a gstreamer plugin that depends on python and gi?

[ben-xD]

Thanks for your reply

I've created a minimum reproducible example on Github (https://github.com/ben-xD/opencv-gstreamer-minimum-example) with your suggested changes to help debug, and have run it to see the output. The app works without pygobject installed into my python environment and I don't think I'm accidentally relying on it.

I'm not trying to use any gstreamer plugins as my pipeline is quite simple:

    pipeline = (
        "udpsrc port=12345 timeout=2000000 ! "
        "application/x-rtp, encoding-name=H264, payload=96 ! "
        "rtph264depay ! "
        "avdec_h264 ! "
        "videoconvert ! "
        "appsink sync=false"
    )

It is my code that triggers the error, so it's not a runtime hook:

cv2.VideoCapture(self.pipeline, cv2.CAP_GSTREAMER)

So for some reason this code works fine before pyinstaller, but after bundling it tries to import gi?

Relevant logs

PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal\lib-dynload): find_spec: called with fullname='gi', target='gi'
PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal\lib-dynload): find_spec: 'gi' not found in PYZ...
PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal\lib-dynload): find_spec: fallback finder is not available.
PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal): find_spec: called with fullname='gi', target='gi'
PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal): find_spec: 'gi' not found in PYZ...
PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal): find_spec: attempting resolve using fallback finder FileFinder('C:\\Users\\admin\\Desktop\\opencv-play\\dist\\Player\\_internal').
PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal): find_spec: fallback finder returned spec: None.
PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal\setuptools\_vendor): find_spec: called with fullname='gi', target='gi'
PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal\setuptools\_vendor): find_spec: 'gi' not found in PYZ...
PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal\setuptools\_vendor): find_spec: attempting resolve using fallback finder FileFinder('C:\\Users\\admin\\Desktop\\opencv-play\\dist\\Player\\_internal\\setuptools\\_vendor').
PyiFrozenFinder(C:\Users\admin\Desktop\opencv-play\dist\Player\_internal\setuptools\_vendor): find_spec: fallback finder returned spec: None.

** (Player.exe:12848): CRITICAL **: 11:07:28.086: pygobject initialization failed: could not import gobject (error was: ModuleNotFoundError("No module named 'gi'"))

I've also attached a file with the full executable's output
opencv-gst-logs.md

[rokm]

Adding GStreamer binaries from C:\Program Files\gstreamer\1.0\msvc_x86_64\lib\gstreamer-1.0
 ...
 - Adding gstpython.dll
 ...

You are collecting the gst-python plugin; and my guess would be that the pygobject initialization failed error message is coming from here.

When you run frozen application, the gstreamer plugins are probably rescanned, which is why you are seeing this message (either because the registry file is not collected, or because plugin location changed). Whereas when you run unfrozen, the gstreamer plugins registry is re-used, and so no scan is necessary - but on the very first run, you might have seen similar error/warning message (or if you remove the registry file to force plugin re-scan).

Does the message go away if you do not collect this plugin? (Or perhaps collect only the plugins that you really require)?

These gi error messages might be a red herring, though, because the actual error message is

[ WARN:0@16.134] global cap_gstreamer.cpp:1777 cv::GStreamerCapture::open OpenCV | GStreamer warning: Cannot query video position: status=1, value=15, duration=-1
Fatal Python error: _PyThreadState_Attach: non-NULL old thread state
Python runtime state: initialized

Current thread 0x00002524 (most recent call first):
  File "main.py", line 21 in capture_frames
  File "threading.py", line 992 in run
  File "threading.py", line 1041 in _bootstrap_inner
  File "threading.py", line 1012 in _bootstrap

Thread 0x00001b30 (most recent call first):
  File "main.py", line 74 in start
  File "main.py", line 99 in <module>

Extension modules: numpy._core._multiarray_umath, numpy.linalg._umath_linalg (total: 2)

(which might or might not be due to the error during plugin scan).

[ben-xD]

Wow, thanks a lot! That definitely fixed it. The error message went away, the app size went from 200MB+ to less than <150MB.

I had a try earlier today where it fixed the error, but I was then having a different error with missing dlls (i removed too much)