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fix(cv): fully purge base OpenCV before reinstalling opencv-python #42

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Merged
rwlove merged 1 commit into from
Jun 12, 2026
Merged

fix(cv): fully purge base OpenCV before reinstalling opencv-python #42

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20 changes: 13 additions & 7 deletions cv/Dockerfile.base
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Original file line number Diff line number Diff line change
Expand Up @@ -63,14 +63,20 @@ RUN --mount=type=cache,target=/root/.cache/pip \
&& rm /tmp/req.txt

# The nvcr.io base ships its own OpenCV (pip package name `opencv`, built
# WITHOUT FFmpeg) which shadows the opencv-python wheel from req.txt — the
# imported cv2 ends up FFMPEG: NO, so cv2.VideoCapture can't open RTSP and
# every camera open fails instantly. Drop the base build and force-reinstall
# the pip wheel (FFMPEG: YES), then assert the backend is present so this
# regression cannot return silently in a future base bump.
# WITHOUT FFmpeg) that installs into the SAME site-packages `cv2/` directory
# as the opencv-python wheel from req.txt and shadows it — `import cv2` loads
# the headless build (FFMPEG: NO), so cv2.VideoCapture can't open RTSP and
# every camera open fails instantly. A plain `pip uninstall` + reinstall is
# not enough: the two packages share the cv2/ dir, so residual files keep
# shadowing the wheel. Purge every opencv variant AND the leftover cv2/ dir,
# then install the opencv-python wheel clean (FFmpeg-enabled on both amd64 and
# arm64), and assert the backend is present so a future base bump can't
# silently reintroduce the regression.
RUN --mount=type=cache,target=/root/.cache/pip \
pip uninstall -y opencv opencv-python opencv-python-headless || true \
&& pip install --force-reinstall --no-deps "opencv-python>=4.10" \
pip uninstall -y opencv opencv-python opencv-python-headless opencv-contrib-python || true \
&& SITE="$(python3 -c 'import site; print(site.getsitepackages()[0])')" \
&& rm -rf "$SITE/cv2" "$SITE"/opencv*.dist-info "$SITE"/opencv_python.libs \
&& pip install --no-cache-dir "opencv-python>=4.10" \
&& python3 -c "import cv2; bi=cv2.getBuildInformation(); assert any('FFMPEG' in l and l.strip().endswith('YES') for l in bi.splitlines()), 'OpenCV FFMPEG backend missing — RTSP capture would fail'; print('cv2', cv2.__version__, 'FFMPEG: YES')"

# Diagnostic: print the compiled arch list so a future regression is
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