The albumentations package requires some version of opencv-python. From setup.py: # If none of packages in first installed, install second package CHOOSE_INSTALL_REQUIRES = [ ( ("opencv-python>=4.1.1", "opencv-contrib-python>=4.1.1", "opencv-contrib-python-headless>=4.1.1"), "opencv-python-headless>=4.1.1", ) ] When I pip install, it seems to choose opencv-python-headless, which has a bug that prevents installation. (If you read the bug, it looks like I could install a different version of scikit-build, but that didn't seem to work.) The workaround is to install a dev version of opencv-python, which I can with this line in requirements.txt: git+https://github.com/opencv/opencv-python@5de8d66d454c8fd946ae17dcfcb285b16aa6049b However, while installing albumentations, it decides to still install opencv-python-headless, presumably because the version number (installed from github) doesn't compare well. How can I install albumentations and have it use my existing opencv-python install? I installed pip-tools, and compiled the requirements for albumentation, and I've been messing with the file, but pip still follows dependencies for each package. Can I use pip to install a package directly, without dependencies? Then I could do it one at a time, with the versions I want. Continue reading...