python - 试图让 OpenCV 3.2.0 与 virtualenv 一起工作

Question

我在 Ubuntu 16.04 上使用 Python 2.7 和 virtualenv & virtualenvwrapper。

关注this guide我设法让以下脚本与我的系统 Python2.7 一起工作，该系统全局安装了 cv2。

我使用这个脚本来安装它:

######################################
# INSTALL OPENCV ON UBUNTU OR DEBIAN #
######################################

# |         THIS SCRIPT IS TESTED CORRECTLY ON         |
# |----------------------------------------------------|
# | OS             | OpenCV       | Test | Last test   |
# |----------------|--------------|------|-------------|
# | Ubuntu 16.04.2 | OpenCV 3.2.0 | OK   | 20 May 2017 |
# | Debian 8.8     | OpenCV 3.2.0 | OK   | 20 May 2017 |
# | Debian 9.0     | OpenCV 3.2.0 | OK   | 25 Jun 2017 |

# 1. KEEP UBUNTU OR DEBIAN UP TO DATE

sudo apt-get -y update
sudo apt-get -y upgrade
sudo apt-get -y dist-upgrade
sudo apt-get -y autoremove


# 2. INSTALL THE DEPENDENCIES

# Build tools:
sudo apt-get install -y build-essential cmake

# GUI (if you want to use GTK instead of Qt, replace 'qt5-default' with 'libgtkglext1-dev' and remove '-DWITH_QT=ON' option in CMake):
sudo apt-get install -y qt5-default libvtk6-dev

# Media I/O:
sudo apt-get install -y zlib1g-dev libjpeg-dev libwebp-dev libpng-dev libtiff5-dev libjasper-dev libopenexr-dev libgdal-dev

# Video I/O:
sudo apt-get install -y libdc1394-22-dev libavcodec-dev libavformat-dev libswscale-dev libtheora-dev libvorbis-dev libxvidcore-dev libx264-dev yasm libopencore-amrnb-dev libopencore-amrwb-dev libv4l-dev libxine2-dev

# Parallelism and linear algebra libraries:
sudo apt-get install -y libtbb-dev libeigen3-dev

# Python:
sudo apt-get install -y python-dev python-tk python-numpy python3-dev python3-tk python3-numpy

# Documentation:
sudo apt-get install -y doxygen

# UI stuff
sudo apt-get install libgtk-3-dev libatlas-base-dev gfortran


# 3. INSTALL THE LIBRARY (YOU CAN CHANGE '3.2.0' FOR THE LAST STABLE VERSION)
sudo apt-get install -y unzip wget

# opencv contrib
wget https://github.com/opencv/opencv_contrib/archive/3.2.0.zip -O opencv_contrib-3.2.0.zip
unzip opencv_contrib-3.2.0.zip
rm opencv_contrib-3.2.0.zip

# opencv
wget https://github.com/opencv/opencv/archive/3.2.0.zip
unzip 3.2.0.zip
rm 3.2.0.zip
mv opencv-3.2.0 OpenCV-3.2.0
cd OpenCV-3.2.0

mkdir build
cd build
cmake -D WITH_QT=ON \
    -D WITH_OPENGL=ON \
    -D FORCE_VTK=ON \
    -D WITH_TBB=ON \
    -D WITH_GDAL=ON \
    -D WITH_XINE=ON \
    -D BUILD_EXAMPLES=ON \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D ENABLE_PRECOMPILED_HEADERS=OFF \
    -D BUILD_NEW_PYTHON_SUPPORT=ON \
    ..

make -j4
sudo make install
sudo ldconfig


# 4. EXECUTE SOME OPENCV EXAMPLES AND COMPILE A DEMONSTRATION

# To complete this step, please visit 'http://milq.github.io/install-opencv-ubuntu-debian'.

下面的脚本非常适用于该系统范围的安装:

import cv2

img = cv2.imread('some_img.jpg')

虽然这个没有 - 即使系统 Python 出于某种原因也无法读取视频...

import cv2

video_capture = cv2.VideoCapture(0)
ret, frame = video_capture.read()
print ret  # always False

但我希望它能与我的 virtualenv 一起工作。所以我重新编译了 OpenCV:

cmake -D WITH_QT=ON \
    -D WITH_OPENGL=ON \
    -D FORCE_VTK=ON \
    -D WITH_TBB=ON \
    -D WITH_GDAL=ON \
    -D WITH_XINE=ON \
    -D BUILD_EXAMPLES=ON \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D ENABLE_PRECOMPILED_HEADERS=OFF \
    -D BUILD_NEW_PYTHON_SUPPORT=ON \
    -D OPENCV_EXTRA_MODULES_PATH=/home/me/code/myproject/opencv_contrib-3.2.0/modules \
    -D PYTHON_EXECUTABLE=~/.envs/myenv/bin/python \
    ..

make -j4
sudo make install
sudo ldconfig

这是 CMake 日志:

-- Found VTK ver. 6.2.0 (usefile: /usr/lib/cmake/vtk-6.2/UseVTK.cmake)
-- Caffe:   NO
-- Protobuf:   YES
-- Glog:   NO
-- freetype2:   YES
-- harfbuzz:    YES
-- Module opencv_sfm disabled because the following dependencies are not found: Glog/Gflags
-- freetype2:   YES
-- harfbuzz:    YES
-- Checking for modules 'tesseract;lept'
--   No package 'tesseract' found
--   No package 'lept' found
-- Tesseract:   NO
-- Check contents of vgg_generated_48.i ...
-- Check contents of vgg_generated_64.i ...
-- Check contents of vgg_generated_80.i ...
-- Check contents of vgg_generated_120.i ...
-- Check contents of boostdesc_bgm.i ...
-- Check contents of boostdesc_bgm_bi.i ...
-- Check contents of boostdesc_bgm_hd.i ...
-- Check contents of boostdesc_binboost_064.i ...
-- Check contents of boostdesc_binboost_128.i ...
-- Check contents of boostdesc_binboost_256.i ...
-- Check contents of boostdesc_lbgm.i ...
-- 
-- General configuration for OpenCV 3.2.0 =====================================
--   Version control:               817bd7b-dirty
-- 
--   Extra modules:
--     Location (extra):            /home/me/code/myproject/opencv_contrib-3.2.0/modules
--     Version control (extra):     817bd7b-dirty
-- 
--   Platform:
--     Timestamp:                   2017-07-20T18:25:26Z
--     Host:                        Linux 4.8.0-58-generic x86_64
--     CMake:                       3.5.1
--     CMake generator:             Unix Makefiles
--     CMake build tool:            /usr/bin/make
--     Configuration:               Release
-- 
--   C/C++:
--     Built as dynamic libs?:      YES
--     C++ Compiler:                /usr/bin/c++  (ver 5.4.0)
--     C++ flags (Release):         -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 -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -msse -msse2 -mno-avx -msse3 -mno-ssse3 -mno-sse4.1 -mno-sse4.2 -ffunction-sections -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG  -DNDEBUG
--     C++ flags (Debug):           -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 -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -msse -msse2 -mno-avx -msse3 -mno-ssse3 -mno-sse4.1 -mno-sse4.2 -ffunction-sections -fvisibility=hidden -fvisibility-inlines-hidden -g  -O0 -DDEBUG -D_DEBUG
--     C Compiler:                  /usr/bin/cc
--     C flags (Release):           -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 -Wno-narrowing -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -msse -msse2 -mno-avx -msse3 -mno-ssse3 -mno-sse4.1 -mno-sse4.2 -ffunction-sections -fvisibility=hidden -O3 -DNDEBUG  -DNDEBUG
--     C flags (Debug):             -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 -Wno-narrowing -Wno-comment -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -msse -msse2 -mno-avx -msse3 -mno-ssse3 -mno-sse4.1 -mno-sse4.2 -ffunction-sections -fvisibility=hidden -g  -O0 -DDEBUG -D_DEBUG
--     Linker flags (Release):
--     Linker flags (Debug):
--     ccache:                      NO
--     Precompiled headers:         NO
--     Extra dependencies:          Qt5::Test Qt5::Concurrent Qt5::OpenGL /usr/lib/x86_64-linux-gnu/libwebp.so /usr/lib/x86_64-linux-gnu/libjasper.so /usr/lib/x86_64-linux-gnu/libImath.so /usr/lib/x86_64-linux-gnu/libIlmImf.so /usr/lib/x86_64-linux-gnu/libIex.so /usr/lib/x86_64-linux-gnu/libHalf.so /usr/lib/x86_64-linux-gnu/libIlmThread.so /usr/lib/libgdal.so dc1394 xine avcodec-ffmpeg avformat-ffmpeg avutil-ffmpeg swscale-ffmpeg Qt5::Core Qt5::Gui Qt5::Widgets /usr/lib/x86_64-linux-gnu/hdf5/serial/lib/libhdf5.so /usr/lib/x86_64-linux-gnu/libpthread.so /usr/lib/x86_64-linux-gnu/libsz.so /usr/lib/x86_64-linux-gnu/libdl.so /usr/lib/x86_64-linux-gnu/libm.so vtkRenderingOpenGL vtkImagingHybrid vtkIOImage vtkCommonDataModel vtkCommonMath vtkCommonCore vtksys vtkCommonMisc vtkCommonSystem vtkCommonTransforms vtkCommonExecutionModel vtkDICOMParser vtkIOCore /usr/lib/x86_64-linux-gnu/libz.so vtkmetaio /usr/lib/x86_64-linux-gnu/libjpeg.so /usr/lib/x86_64-linux-gnu/libpng.so /usr/lib/x86_64-linux-gnu/libtiff.so vtkImagingCore vtkRenderingCore vtkCommonColor vtkFiltersExtraction vtkFiltersCore vtkFiltersGeneral vtkCommonComputationalGeometry vtkFiltersStatistics vtkImagingFourier vtkalglib vtkFiltersGeometry vtkFiltersSources vtkInteractionStyle vtkRenderingLOD vtkFiltersModeling vtkIOPLY vtkIOGeometry /usr/lib/x86_64-linux-gnu/libjsoncpp.so vtkFiltersTexture vtkRenderingFreeType /usr/lib/x86_64-linux-gnu/libfreetype.so vtkftgl vtkIOExport vtkRenderingAnnotation vtkImagingColor vtkRenderingContext2D vtkRenderingGL2PS vtkRenderingContextOpenGL /usr/lib/libgl2ps.so vtkRenderingLabel dl m pthread rt /usr/lib/x86_64-linux-gnu/libGLU.so /usr/lib/x86_64-linux-gnu/libGL.so tbb
--     3rdparty dependencies:       libprotobuf
-- 
--   OpenCV modules:
--     To be built:                 core flann hdf imgproc ml photo reg surface_matching video viz dnn freetype fuzzy imgcodecs shape videoio highgui objdetect plot superres ts xobjdetect xphoto bgsegm bioinspired dpm face features2d line_descriptor saliency text calib3d ccalib cvv datasets rgbd stereo tracking videostab xfeatures2d ximgproc aruco optflow phase_unwrapping stitching structured_light java python2 python3
--     Disabled:                    world contrib_world
--     Disabled by dependency:      -
--     Unavailable:                 cudaarithm cudabgsegm cudacodec cudafeatures2d cudafilters cudaimgproc cudalegacy cudaobjdetect cudaoptflow cudastereo cudawarping cudev cnn_3dobj matlab sfm
-- 
--   GUI: 
--     QT 5.x:                      YES (ver 5.5.1)
--     QT OpenGL support:           YES (Qt5::OpenGL 5.5.1)
--     OpenGL support:              YES (/usr/lib/x86_64-linux-gnu/libGLU.so /usr/lib/x86_64-linux-gnu/libGL.so)
--     VTK support:                 YES (ver 6.2.0)
-- 
--   Media I/O: 
--     ZLib:                        /usr/lib/x86_64-linux-gnu/libz.so (ver 1.2.8)
--     JPEG:                        /usr/lib/x86_64-linux-gnu/libjpeg.so (ver )
--     WEBP:                        /usr/lib/x86_64-linux-gnu/libwebp.so (ver encoder: 0x0202)
--     PNG:                         /usr/lib/x86_64-linux-gnu/libpng.so (ver 1.2.54)
--     TIFF:                        /usr/lib/x86_64-linux-gnu/libtiff.so (ver 42 - 4.0.6)
--     JPEG 2000:                   /usr/lib/x86_64-linux-gnu/libjasper.so (ver 1.900.1)
--     OpenEXR:                     /usr/lib/x86_64-linux-gnu/libImath.so /usr/lib/x86_64-linux-gnu/libIlmImf.so /usr/lib/x86_64-linux-gnu/libIex.so /usr/lib/x86_64-linux-gnu/libHalf.so /usr/lib/x86_64-linux-gnu/libIlmThread.so (ver 2.2.0)
--     GDAL:                        /usr/lib/libgdal.so
--     GDCM:                        NO
-- 
--   Video I/O:
--     DC1394 1.x:                  NO
--     DC1394 2.x:                  YES (ver 2.2.4)
--     FFMPEG:                      YES
--       avcodec:                   YES (ver 56.60.100)
--       avformat:                  YES (ver 56.40.101)
--       avutil:                    YES (ver 54.31.100)
--       swscale:                   YES (ver 3.1.101)
--       avresample:                NO
--     GStreamer:                   NO
--     OpenNI:                      NO
--     OpenNI PrimeSensor Modules:  NO
--     OpenNI2:                     NO
--     PvAPI:                       NO
--     GigEVisionSDK:               NO
--     Aravis SDK:                  NO
--     UniCap:                      NO
--     UniCap ucil:                 NO
--     V4L/V4L2:                    NO/YES
--     XIMEA:                       NO
--     Xine:                        YES (ver 1.2.6)
--     gPhoto2:                     NO
-- 
--   Parallel framework:            TBB (ver 4.4 interface 9002)
-- 
--   Other third-party libraries:
--     Use IPP:                     9.0.1 [9.0.1]
--          at:                     /home/me/code/myproject/OpenCV-3.2.0/build/3rdparty/ippicv/ippicv_lnx
--     Use IPP Async:               NO
--     Use VA:                      NO
--     Use Intel VA-API/OpenCL:     NO
--     Use Lapack:                  NO
--     Use Eigen:                   YES (ver 3.2.92)
--     Use Cuda:                    NO
--     Use OpenCL:                  YES
--     Use OpenVX:                  NO
--     Use custom HAL:              NO
-- 
--   OpenCL:                        <Dynamic loading of OpenCL library>
--     Include path:                /home/me/code/myproject/OpenCV-3.2.0/3rdparty/include/opencl/1.2
--     Use AMDFFT:                  NO
--     Use AMDBLAS:                 NO
-- 
--   Python 2:
--     Interpreter:                 /home/me/.envs/myenv/bin/python (ver 2.7.12)
--     Libraries:                   /usr/lib/x86_64-linux-gnu/libpython2.7.so (ver 2.7.12)
--     numpy:                       /home/me/.envs/myenv/local/lib/python2.7/site-packages/numpy/core/include (ver 1.13.1)
--     packages path:               lib/python2.7/site-packages
-- 
--   Python 3:
--     Interpreter:                 /usr/bin/python3 (ver 3.5.2)
--     Libraries:                   /usr/lib/x86_64-linux-gnu/libpython3.5m.so (ver 3.5.2)
--     numpy:                       /usr/lib/python3/dist-packages/numpy/core/include (ver 1.11.0)
--     packages path:               lib/python3.5/dist-packages
-- 
--   Python (for build):            /home/me/.envs/myenv/bin/python
-- 
--   Java:
--     ant:                         /usr/bin/ant (ver 1.9.6)
--     JNI:                         /usr/lib/jvm/default-java/include /usr/lib/jvm/default-java/include/linux /usr/lib/jvm/default-java/include
--     Java wrappers:               YES
--     Java tests:                  YES
-- 
--   Matlab:                        Matlab not found or implicitly disabled
-- 
--   Documentation:
--     Doxygen:                     /usr/bin/doxygen (ver 1.8.11)
-- 
--   Tests and samples:
--     Tests:                       YES
--     Performance tests:           YES
--     C/C++ Examples:              YES
-- 
--   Install path:                  /usr/local
-- 
--   cvconfig.h is in:              /home/me/code/myproject/OpenCV-3.2.0/build
-- -----------------------------------------------------------------
-- 

不幸的是，虽然这可行并且我可以在 shell 中导入 cv2，但它无法使用上述脚本读取视频，这可能是由于 ffmpeg 的编译或链接不正确？令人困惑的部分是 OpenCV 的系统范围安装工作正常，即使没有安装 ffmpeg!

我做错了什么？我怎样才能让 OpenCV 与 virtualenv 一起工作？

====

编辑:运行 C++ 视频编写示例有这样的结果:

$ cd /home/me/code/myproject/OpenCV-3.2.0/build/bin
$ ./cpp-tutorial-video-write ../../samples/data/vtest.avi R Y
------------------------------------------------------------------------------
This program shows how to write video files.
You can extract the R or G or B color channel of the input video.
Usage:
./video-write <input_video_name> [ R | G | B] [Y | N]
------------------------------------------------------------------------------

OpenCV: FFMPEG: tag 0xffffffff/'����' is not found (format 'avi / AVI (Audio Video Interleaved)')'

(cpp-tutorial-video-write:19523): GStreamer-CRITICAL **: gst_element_make_from_uri: assertion 'gst_uri_is_valid (uri)' failed
OpenCV Error: Unsupported format or combination of formats (Gstreamer Opencv backend does not support this codec.) in CvVideoWriter_GStreamer::open, file /home/me/code/myproject/OpenCV-3.2.0/modules/videoio/src/cap_gstreamer.cpp, line 1388
VIDEOIO(cvCreateVideoWriter_GStreamer(filename, fourcc, fps, frameSize, is_color)): raised OpenCV exception:

/home/me/code/myproject/OpenCV-3.2.0/modules/videoio/src/cap_gstreamer.cpp:1388: error: (-210) Gstreamer Opencv backend does not support this codec. in function CvVideoWriter_GStreamer::open

Could not open the output video for write: ../../samples/data/vtest.avi

opencv_test_videoio 单元测试报告如下:https://pastebin.com/q4mf224Q

但是，运行 c++ video starter 示例确实有效，使用以下命令和输出，我可以在 highgui 界面中看到网络摄像头工作和流式传输视频:

$ ./cpp-example-videocapture_starter 0
VIDEOIO ERROR: V4L: device 0: Unable to query number of channels
(ERROR)icvOpenAVI_XINE(): Unable to initialize video driver.
GStreamer: Error opening bin: no element "0"
press space to save a picture. q or esc to quit
init done
opengl support available

Answer 1

根据指南，您安装了libavcodec-dev libavformat-dev libswscale-dev libv4l-dev这是使用相机和解码音频/视频流所必需的。

我认为 CMake 输出/日志应该给了您一些提示，我建议您向我们提供此日志的 pastebin/gist 链接。

例如，您在 CMake 日志中的这一行下面有什么？ (你应该有很多是)

-- Video I/O:

在这一个:

-- OpenCV modules:
-- To be built: <list of opencv modules>

是否 <list of opencv modules>包含“videoio”？

另一个愚蠢的测试:你的相机能用吗？你有/dev/video0 文件吗？你能看到带有 vlc 或 cheese 的视频流吗？

---

编辑

我看到你没有 gstreamer，您能否尝试安装以下库:libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev并重新编译？

V4L2 应该足够了，你有，但是according to the sources gstreamer 也可用于视频捕获。因此，解决您的问题的可能性很小但不可忽略。

其他问题:

• 当您使用视频文件而不是网络摄像头时会发生什么？
• 我看到(单元)测试已编译，它们都通过了吗？
• 我看到 cpp 样本已编译，你能试试 cpp-example-videocapture_basic或 cpp-example-videocapture_starter , 他们会给你一个错误吗？