python 使用cv2读取mp4视频失败的解决方法
python 使用cv2读取mp4视频失败的解决方法
- cv2读取视频失败描述
- 相关环境配置
- 代码部分
- terminal输出
- 读取失败分析
- 失败解决方案
- 最终解决方案
- 修改opencv版本
- 安装相关配置
- 结果展示
如果试遍全网方法仍用cv2读取不了视频，那么以下将是你解决问题前读过的最后一篇文章！！！
创作背景：博主今天很生气，也很郁闷，花了一下午时间，啥都没做，用cv2读取mp4视频，一直Opened()输出为Flase，一直显示打印出来的视频fps为0！！！这是为什么？？？在尝试了全网近乎所有解决cv2读取视频失败的方法之后，我对我的配置下读取失败的原因进行了分析，并给出本csdn下最终的解决方案。
cv2读取视频失败描述
博主使用的环境是服务器下linux-terminal（如果您使用python opencv-python在本地电脑，本文对您的帮助可能不是很大）
相关环境配置
python版本：3.6.9
opencv-python版本： 3.2.0.8（3.3.0.10版本以下均可）
代码部分
video_path = "path/to/my/video"
img_path = "path/to/my/save"
cap = cv2.VideoCapture()
cap.open(video_path)
fps = cap.get(cv2.CAP_PROP_FPS)
width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
print(fps, width, height)
suc = cap.isOpened()
print(suc)
frame_count = 0
while suc:frame_count += 1suc, frame = cap.read()cv2.imwrite(img_path + str(frame_count), frame)cv2.waitKey(1)
cap.release()
print('End!')
terminal输出
0.0 0 0
False
End!
读取失败分析
容易发现，terminal没有输出代码报错的位置，说明代码是没问题的。
此外，代码suc变量print出的结果是False，说明cv2没有按照我们给出视频地址读取对应的视频。
综上，我们有如下无法读取视频的分析：
1、视频路径错误；
2、opencv读取视频问题。
对于1，我们尝试更换其他视频，发现同样无法读取该视频；尝试更换视频格式（由mp4换成avi），发现还是无法读取该视频，我们有理由相信原有视频路径是没问题的。那么就是opencv的问题了。
对于2，根据网上print出当下opencv信息的方法：
import cv2
print(cv2.getBuildInformation())
我们可以得到如下的opencv信息：
General configuration for OpenCV 3.3.0 =====================================Version control: 3.3.0Platform:Timestamp: 2017-08-12T18:35:30ZHost: Linux 4.4.0-83-generic x86_64CMake: 3.9.0CMake generator: Unix MakefilesCMake build tool: /usr/bin/gmakeConfiguration: ReleaseCPU/HW features:Baseline: SSE SSE2 SSE3requested: SSE3Dispatched code generation: SSE4_1 SSE4_2 FP16 AVX AVX2requested: SSE4_1 SSE4_2 AVX FP16 AVX2SSE4_1 (2 files): + SSSE3 SSE4_1SSE4_2 (1 files): + SSSE3 SSE4_1 POPCNT SSE4_2FP16 (1 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 AVXAVX (5 files): + SSSE3 SSE4_1 POPCNT SSE4_2 AVXAVX2 (7 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2C/C++:Built as dynamic libs?: NOC++ Compiler: /opt/rh/devtoolset-2/root/usr/bin/c++ (ver 4.8.2)C++ flags (Release): -fPIC -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG -DNDEBUGC++ flags (Debug): -fPIC -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -g -O0 -DDEBUG -D_DEBUGC Compiler: /opt/rh/devtoolset-2/root/usr/bin/ccC flags (Release): -fPIC -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Winit-self -Wno-narrowing -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -msse -msse2 -msse3 -fvisibility=hidden -O3 -DNDEBUG -DNDEBUGC flags (Debug): -fPIC -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Winit-self -Wno-narrowing -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -msse -msse2 -msse3 -fvisibility=hidden -g -O0 -DDEBUG -D_DEBUGLinker flags (Release):Linker flags (Debug):ccache: NOPrecompiled headers: YESExtra dependencies: gthread-2.0 glib-2.0 /lib64/libz.so stdc++ dl m pthread rt3rdparty dependencies: ittnotify libprotobuf libjpeg libwebp libpng libtiff libjasper IlmImfOpenCV modules:To be built: core flann imgproc ml objdetect photo video dnn imgcodecs shape videoio highgui superres features2d calib3d stitching videostab python3Disabled: worldDisabled by dependency: -Unavailable: cudaarithm cudabgsegm cudacodec cudafeatures2d cudafilters cudaimgproc cudalegacy cudaobjdetect cudaoptflow cudastereo cudawarping cudev java python2 ts vizGUI:QT: NOGTK+: NOGThread : YES (ver 2.12.3)GtkGlExt: NOOpenGL support: NOVTK support: NOMedia I/O:ZLib: /lib64/libz.so (ver 1.2.3)JPEG: libjpeg (ver 90)WEBP: build (ver encoder: 0x020e)PNG: build (ver 1.6.24)TIFF: build (ver 42 - 4.0.2)JPEG 2000: build (ver 1.900.1)OpenEXR: build (ver 1.7.1)GDAL: NOGDCM: NOVideo I/O:DC1394 1.x: NODC1394 2.x: NOFFMPEG: NOavcodec: NOavformat: NOavutil: NOswscale: NOavresample: NOGStreamer: NOOpenNI: NOOpenNI PrimeSensor Modules: NOOpenNI2: NOPvAPI: NOGigEVisionSDK: NOAravis SDK: NOUniCap: NOUniCap ucil: NOV4L/V4L2: NO/NOXIMEA: NOXine: NOIntel Media SDK: NOgPhoto2: NOParallel framework: pthreadsTrace: YES (with Intel ITT)Other third-party libraries:Use Intel IPP: NOUse Intel IPP IW: NOUse Intel IPP Async: NOUse VA: NOUse Intel VA-API/OpenCL: NOUse Lapack: NOUse Eigen: NOUse Cuda: NOUse OpenCL: YESUse OpenVX: NOUse custom HAL: NOOpenCL: Include path: /io/opencv/3rdparty/include/opencl/1.2Use AMDFFT: NOUse AMDBLAS: NOPython 2:Interpreter: NOPython 3:Interpreter: python (ver 3.6.0)Libraries:numpy: /opt/python/cp36-cp36m/lib/python3.6/site-packages/numpy/core/include (ver 1.11.3)packages path: /opt/python/cp36-cp36m/lib/python3.6/site-packagesPython (for build): pythonJava:ant: NOJNI: NOJava wrappers: NOJava tests: NOMatlab: Matlab not found or implicitly disabledTests and samples:Tests: NOPerformance tests: NOC/C++ Examples: NOInstall path: /usr/localcvconfig.h is in: /io/opencv/build
-----------------------------------------------------------------
容易发现，video下方基本都是NO，最终我们确定是opencv的问题。
失败解决方案
1、网上说没有安装ffmpeg库，我们尝试安装此库，发现并不能解决问题。
2、没有安装opencv-contrib-python-headless，我们尝试安装此库，发现并不能解决问题。
3、opencv库里面dll文件异常，我们尝试修改dll文件，发现并不能解决问题。
最终解决方案
修改opencv版本
我们尝试提高opencv版本，将原来的3.2.0.8版本更新到4.1.1版本及以上，令我们出乎意料的是这个方法将上述遇到的问题解决了，下面将分享我们解决问题的过程和方法。
安装相关配置
我们尝试根据如下指令提高opencv的版本：
pip install opencv-python==4.1.1.26
之后运行代码，发现出现如下报错：
ImportError: libSM.so.6: cannot open shared object file: No such file or directory
依次运行如下命令，即可解决此报错：
apt-get update （选择）
apt-get install sudo （选择）
sudo apt-get install libsm6
sudo apt-get install libxrender1
sudo apt-get install libxext-dev
结果展示
再次查看opencv信息：
General configuration for OpenCV 4.1.1 =====================================Version control: 4.1.1Platform:Timestamp: 2019-09-02T14:45:10ZHost: Linux 4.15.0-1028-gcp x86_64CMake: 3.9.0CMake generator: Unix MakefilesCMake build tool: /usr/bin/gmakeConfiguration: ReleaseCPU/HW features:Baseline: SSE SSE2 SSE3requested: SSE3Dispatched code generation: SSE4_1 SSE4_2 FP16 AVX AVX2requested: SSE4_1 SSE4_2 AVX FP16 AVX2 AVX512_SKXSSE4_1 (13 files): + SSSE3 SSE4_1SSE4_2 (1 files): + SSSE3 SSE4_1 POPCNT SSE4_2FP16 (0 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 AVXAVX (4 files): + SSSE3 SSE4_1 POPCNT SSE4_2 AVXAVX2 (27 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2C/C++:Built as dynamic libs?: NOC++ Compiler: /usr/lib/ccache/compilers/c++ (ver 4.8.2)C++ flags (Release): -Wl,-strip-all -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wsign-promo -Wuninitialized -Winit-self -Wno-delete-non-virtual-dtor -Wno-comment -Wno-missing-field-initializers -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG -DNDEBUGC++ flags (Debug): -Wl,-strip-all -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wsign-promo -Wuninitialized -Winit-self -Wno-delete-non-virtual-dtor -Wno-comment -Wno-missing-field-initializers -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -g -O0 -DDEBUG -D_DEBUGC Compiler: /usr/lib/ccache/compilers/ccC flags (Release): -Wl,-strip-all -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wuninitialized -Winit-self -Wno-comment -Wno-missing-field-initializers -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -msse -msse2 -msse3 -fvisibility=hidden -O3 -DNDEBUG -DNDEBUGC flags (Debug): -Wl,-strip-all -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wuninitialized -Winit-self -Wno-comment -Wno-missing-field-initializers -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -msse -msse2 -msse3 -fvisibility=hidden -g -O0 -DDEBUG -D_DEBUGLinker flags (Release): -L/root/ffmpeg_build/lib -Wl,--gc-sectionsLinker flags (Debug): -L/root/ffmpeg_build/lib -Wl,--gc-sectionsccache: YESPrecompiled headers: NOExtra dependencies: ade /opt/Qt4.8.7/lib/libQtGui.so /opt/Qt4.8.7/lib/libQtTest.so /opt/Qt4.8.7/lib/libQtCore.so /lib64/libz.so dl m pthread rt3rdparty dependencies: ittnotify libprotobuf libjpeg-turbo libwebp libpng libtiff libjasper IlmImf quircOpenCV modules:To be built: calib3d core dnn features2d flann gapi highgui imgcodecs imgproc ml objdetect photo python3 stitching video videoioDisabled: worldDisabled by dependency: -Unavailable: java js python2 tsApplications: -Documentation: NONon-free algorithms: NOGUI:QT: YES (ver 4.8.7 EDITION = OpenSource)QT OpenGL support: NOGTK+: NOVTK support: NOMedia I/O:ZLib: /lib64/libz.so (ver 1.2.3)JPEG: libjpeg-turbo (ver 2.0.2-62)WEBP: build (ver encoder: 0x020e)PNG: build (ver 1.6.37)TIFF: build (ver 42 - 4.0.10)JPEG 2000: build (ver 1.900.1)OpenEXR: build (ver 2.3.0)HDR: YESSUNRASTER: YESPXM: YESPFM: YESVideo I/O:DC1394: NOFFMPEG: YESavcodec: YES (58.55.100)avformat: YES (58.31.101)avutil: YES (56.33.100)swscale: YES (5.6.100)avresample: NOGStreamer: NOv4l/v4l2: YES (linux/videodev2.h)Parallel framework: pthreadsTrace: YES (with Intel ITT)Other third-party libraries:Lapack: NOEigen: NOCustom HAL: NOProtobuf: build (3.5.1)OpenCL: YES (no extra features)Include path: /io/opencv/3rdparty/include/opencl/1.2Link libraries: Dynamic loadPython 3:Interpreter: /opt/python/cp36-cp36m/bin/python (ver 3.6.9)Libraries: libpython3.6m.a (ver 3.6.9)numpy: /opt/python/cp36-cp36m/lib/python3.6/site-packages/numpy/core/include (ver 1.11.3)install path: pythonPython (for build): /opt/python/cp36-cp36m/bin/pythonJava:ant: NOJNI: NOJava wrappers: NOJava tests: NOInstall to: /io/_skbuild/linux-x86_64-3.6/cmake-install
-----------------------------------------------------------------
显然，video下方已经由NO变成YES。
再次运行代码，terminal输出结果：
59.94005994005994 1920 1080
True
End！
fps、视频长宽均正常输出，且视频正常打开，问题解决！
希望此分享能帮助遇到同样问题的您！
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