使用Python调用OpenCV遇导入错误，求助解决方案

问题描述 #

此前使用OpenCV完全正常，近期运行哪怕是显示图片这类基础Python程序，都会立刻抛出错误。错误栈显示导入cv2时，无法找到FFmpeg相关依赖库：libswresample.4.dylib、libavcodec.59.dylib、libavutil.57.dylib，已尝试卸载重装OpenCV但问题依旧。

错误信息 #

Traceback (most recent call last):
  File "/Users/myusername/Desktop/opencv_test_main/opencv.py", line 1, in <module>
    import cv2
  File "/opt/homebrew/lib/python3.10/site-packages/cv2/__init__.py", line 181, in <module>
    bootstrap()
  File "/opt/homebrew/lib/python3.10/site-packages/cv2/__init__.py", line 153, in bootstrap
    native_module = importlib.import_module("cv2")
  File "/opt/homebrew/Cellar/python@3.10/3.10.8/Frameworks/Python.framework/Versions/3.10/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
ImportError: dlopen(/opt/homebrew/lib/python3.10/site-packages/cv2/python-3.10/cv2.cpython-310-darwin.so, 0x0002): Library not loaded: /opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libswresample.4.dylib
  Referenced from: <D8B40CEE-FD64-33D7-9FBB-D99C076CAE66> /opt/homebrew/Cellar/ffmpeg/5.1.2.reinstall/lib/libavcodec.59.37.100.dylib
  Reason: tried: '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libswresample.4.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libswresample.4.dylib' (no such file), '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libswresample.4.dylib' (no such file), '/usr/local/lib/libswresample.4.dylib' (no such file), '/usr/lib/libswresample.4.dylib' (no such file, not in dyld cache)Library not loaded: /opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavcodec.59.dylib
  Referenced from: <D8E78893-F144-3845-A719-8CFFB8415DC1> /opt/homebrew/Cellar/ffmpeg/5.1.2.reinstall/lib/libavformat.59.27.100.dylib
  Reason: tried: '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavcodec.59.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavcodec.59.dylib' (no such file), '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavcodec.59.dylib' (no such file), '/usr/local/lib/libavcodec.59.dylib' (no such file), '/usr/lib/libavcodec.59.dylib' (no such file, not in dyld cache)Library not loaded: /opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavutil.57.dylib
  Referenced from: <13009670-C126-334B-9BAE-6C052B28BDCE> /opt/homebrew/Cellar/ffmpeg/5.1.2.reinstall/lib/libswscale.6.7.100.dylib
  Reason: tried: '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavutil.57.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavutil.57.dylib' (no such file), '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavutil.57.dylib' (no such file), '/usr/local/lib/libavutil.57.dylib' (no such file), '/usr/lib/libavutil.57.dylib' (no such file, not in dyld cache)
myusername@Zachs-MBP-2 opencv_test_main % /opt/homebrew/bin/python3 /Users/myusername/Desktop/opencv_test_main/opencv_test.py
Traceback (most recent call last):
  File "/Users/myusername/Desktop/opencv_test_main/opencv_test.py", line 1, in <module>
    import cv2
  File "/opt/homebrew/lib/python3.10/site-packages/cv2/__init__.py", line 181, in <module>
    bootstrap()
  File "/opt/homebrew/lib/python3.10/site-packages/cv2/__init__.py", line 153, in bootstrap
    native_module = importlib.import_module("cv2")
  File "/opt/homebrew/Cellar/python@3.10/3.10.8/Frameworks/Python.framework/Versions/3.10/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
ImportError: dlopen(/opt/homebrew/lib/python3.10/site-packages/cv2/python-3.10/cv2.cpython-310-darwin.so, 0x0002): Library not loaded: /opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libswresample.4.dylib
  Referenced from: <D8B40CEE-FD64-33D7-9FBB-D99C076CAE66> /opt/homebrew/Cellar/ffmpeg/5.1.2.reinstall/lib/libavcodec.59.37.100.dylib
  Reason: tried: '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libswresample.4.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libswresample.4.dylib' (no such file), '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libswresample.4.dylib' (no such file), '/usr/local/lib/libswresample.4.dylib' (no such file), '/usr/lib/libswresample.4.dylib' (no such file, not in dyld cache)Library not loaded: /opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavcodec.59.dylib
  Referenced from: <D8E78893-F144-3845-A719-8CFFB8415DC1> /opt/homebrew/Cellar/ffmpeg/5.1.2.reinstall/lib/libavformat.59.27.100.dylib
  Reason: tried: '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavcodec.59.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavcodec.59.dylib' (no such file), '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavcodec.59.dylib' (no such file), '/usr/local/lib/libavcodec.59.dylib' (no such file), '/usr/lib/libavcodec.59.dylib' (no such file, not in dyld cache)Library not loaded: /opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavutil.57.dylib
  Referenced from: <13009670-C126-334B-9BAE-6C052B28BDCE> /opt/homebrew/Cellar/ffmpeg/5.1.2.reinstall/lib/libswscale.6.7.100.dylib
  Reason: tried: '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavutil.57.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavutil.57.dylib' (no such file), '/opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavutil.57.dylib' (no such file), '/usr/local/lib/libavutil.57.dylib' (no such file), '/usr/lib/libavutil.57.dylib' (no such file, not in dyld cache)

解决步骤 #

1. 安装对应版本的FFmpeg #

错误提示中OpenCV依赖的是FFmpeg 5.1.2版本，直接安装该版本：

brew install ffmpeg@5.1

安装完成后，强制链接该版本到系统路径：

brew link --force ffmpeg@5.1

2. 重新安装带FFmpeg支持的OpenCV #

如果上面的步骤无效，卸载当前OpenCV后，重新安装带有FFmpeg依赖的版本：

pip uninstall opencv-python opencv-contrib-python -y
pip install opencv-python --no-binary opencv-python

或者用Homebrew直接安装OpenCV（确保关联FFmpeg）：

brew uninstall opencv
brew install opencv --with-ffmpeg

3. 修复动态链接库路径 #

如果FFmpeg已安装但路径不匹配，可以用otool和install_name_tool手动修复cv2的动态链接：
首先查看cv2库依赖的FFmpeg路径：

otool -L /opt/homebrew/lib/python3.10/site-packages/cv2/python-3.10/cv2.cpython-310-darwin.so | grep ffmpeg

然后替换错误的路径为当前FFmpeg的实际路径（假设当前FFmpeg安装在/opt/homebrew/Cellar/ffmpeg/5.1.2.reinstall）：

install_name_tool -change /opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libswresample.4.dylib /opt/homebrew/Cellar/ffmpeg/5.1.2.reinstall/lib/libswresample.4.dylib /opt/homebrew/lib/python3.10/site-packages/cv2/python-3.10/cv2.cpython-310-darwin.so
install_name_tool -change /opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavcodec.59.dylib /opt/homebrew/Cellar/ffmpeg/5.1.2.reinstall/lib/libavcodec.59.dylib /opt/homebrew/lib/python3.10/site-packages/cv2/python-3.10/cv2.cpython-310-darwin.so
install_name_tool -change /opt/homebrew/Cellar/ffmpeg/5.1.2/lib/libavutil.57.dylib /opt/homebrew/Cellar/ffmpeg/5.1.2.reinstall/lib/libavutil.57.dylib /opt/homebrew/lib/python3.10/site-packages/cv2/python-3.10/cv2.cpython-310-darwin.so

4. 检查Python环境 #

如果使用虚拟环境，确保激活对应的环境后再安装OpenCV和FFmpeg相关依赖，避免全局环境和虚拟环境的依赖冲突。

内容的提问来源于stack exchange，提问作者Velocity Games