cv.VideoCapture can't load video properly

[junzhou502]

Expected behaviour

When I load a video like, cap = cv.VideoCapture('xx.avi')
cap.isOpened() should return a True value

Actual behaviour

However cap.isOpened() always return a False value

Steps to reproduce

It's said that this problem is something about .dll file, however I cannot find those files in my disk. Can anyone help to check the build information and see what happend?

I pip install opencv-python on VScode(windows10) and the build information is:

General configuration for OpenCV 4.10.0 =====================================
  Version control:               4.10.0

  Extra modules:
    Location (extra):            D:/a/opencv-python/opencv-python/opencv_contrib/modules
    Version control (extra):     4.10.0

  Platform:
    Timestamp:                   2024-06-17T18:00:01Z
    Host:                        Windows 10.0.17763 AMD64
    CMake:                       3.24.2
    CMake generator:             Visual Studio 14 2015
    CMake build tool:            MSBuild.exe
    MSVC:                        1900
    Configuration:               Debug Release

  CPU/HW features:
    Baseline:                    SSE SSE2 SSE3
      requested:                 SSE3
    Dispatched code generation:  SSE4_1 SSE4_2 FP16 AVX AVX2
      requested:                 SSE4_1 SSE4_2 AVX FP16 AVX2 AVX512_SKX
      SSE4_1 (16 files):         + SSSE3 SSE4_1
      SSE4_2 (1 files):          + SSSE3 SSE4_1 POPCNT SSE4_2
      FP16 (0 files):            + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 AVX
      AVX (8 files):             + SSSE3 SSE4_1 POPCNT SSE4_2 AVX
      AVX2 (36 files):           + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2

  C/C++:
    Built as dynamic libs?:      NO
    C++ standard:                11
    C++ Compiler:                C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/x86_amd64/cl.exe  (ver 19.0.24247.2)
    C++ flags (Release):         /DWIN32 /D_WINDOWS /W4 /GR  /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /Oi  /fp:precise     /EHa /wd4127 /wd4251 /wd4324 /wd4275 /wd4512 /wd4589 /wd4819 /MP  /O2 /Ob2 /DNDEBUG
    C++ flags (Debug):           /DWIN32 /D_WINDOWS /W4 /GR  /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /Oi  /fp:precise     /EHa /wd4127 /wd4251 /wd4324 /wd4275 /wd4512 /wd4589 /wd4819 /MP  /Zi /Ob0 /Od /RTC1
    C Compiler:                  C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/x86_amd64/cl.exe
    C flags (Release):           /DWIN32 /D_WINDOWS /W3  /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /Oi  /fp:precise     /MP   /O2 /Ob2 /DNDEBUG
    C flags (Debug):             /DWIN32 /D_WINDOWS /W3  /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /Oi  /fp:precise     /MP /Zi /Ob0 /Od /RTC1
    Linker flags (Release):      /machine:x64  /NODEFAULTLIB:atlthunk.lib /INCREMENTAL:NO  /NODEFAULTLIB:libcmtd.lib /NODEFAULTLIB:libcpmtd.lib /NODEFAULTLIB:msvcrtd.lib
    Linker flags (Debug):        /machine:x64  /NODEFAULTLIB:atlthunk.lib /debug /INCREMENTAL  /NODEFAULTLIB:libcmt.lib /NODEFAULTLIB:libcpmt.lib /NODEFAULTLIB:msvcrt.lib
    ccache:                      NO
    Precompiled headers:         YES
    Extra dependencies:          wsock32 comctl32 gdi32 ole32 setupapi ws2_32
    3rdparty dependencies:       libprotobuf ade ittnotify libjpeg-turbo libwebp libpng libtiff libopenjp2 IlmImf zlib 
ippiw ippicv

  OpenCV modules:
    To be built:                 aruco bgsegm bioinspired calib3d ccalib core datasets dnn dnn_objdetect dnn_superres dpm face features2d flann fuzzy gapi hfs highgui img_hash imgcodecs imgproc intensity_transform line_descriptor mcc ml objdetect optflow phase_unwrapping photo plot python3 quality rapid reg rgbd saliency shape signal stereo stitching structured_light superres surface_matching text tracking video videoio videostab wechat_qrcode xfeatures2d ximgproc xobjdetect xphoto
    Disabled:                    java world
    Disabled by dependency:      -
    Unavailable:                 alphamat cannops cudaarithm cudabgsegm cudacodec cudafeatures2d cudafilters cudaimgproc cudalegacy cudaobjdetect cudaoptflow cudastereo cudawarping cudev cvv freetype hdf julia matlab ovis python2 sfm ts viz
    Applications:                -
    Documentation:               NO
    Non-free algorithms:         NO

  Windows RT support:            NO

  GUI:                           WIN32UI
    Win32 UI:                    YES
    VTK support:                 NO

  Media I/O:
    ZLib:                        build (ver 1.3.1)
    JPEG:                        build-libjpeg-turbo (ver 3.0.3-70)
      SIMD Support Request:      YES
      SIMD Support:              NO
    WEBP:                        build (ver encoder: 0x020f)
    PNG:                         build (ver 1.6.43)
      SIMD Support Request:      YES
      SIMD Support:              YES (Intel SSE)
    TIFF:                        build (ver 42 - 4.6.0)
    JPEG 2000:                   build (ver 2.5.0)
    OpenEXR:                     build (ver 2.3.0)
    HDR:                         YES
    SUNRASTER:                   YES
    PXM:                         YES
    PFM:                         YES

  Video I/O:
    DC1394:                      NO
    FFMPEG:                      YES (prebuilt binaries)
      avcodec:                   YES (58.134.100)
      avformat:                  YES (58.76.100)
      avutil:                    YES (56.70.100)
      swscale:                   YES (5.9.100)
      avresample:                YES (4.0.0)
    GStreamer:                   NO
    DirectShow:                  YES
    Media Foundation:            YES
      DXVA:                      YES

  Parallel framework:            Concurrency

  Trace:                         YES (with Intel ITT)

  Other third-party libraries:
    Intel IPP:                   2021.11.0 [2021.11.0]
           at:                   D:/a/opencv-python/opencv-python/_skbuild/win-amd64-3.9/cmake-build/3rdparty/ippicv/ippicv_win/icv
    Intel IPP IW:                sources (2021.11.0)
              at:                D:/a/opencv-python/opencv-python/_skbuild/win-amd64-3.9/cmake-build/3rdparty/ippicv/ippicv_win/iw
    Lapack:                      NO
    Eigen:                       NO
    Custom HAL:                  NO
    Protobuf:                    build (3.19.1)
    Flatbuffers:                 builtin/3rdparty (23.5.9)

  OpenCL:                        YES (NVD3D11)
    Include path:                D:/a/opencv-python/opencv-python/opencv/3rdparty/include/opencl/1.2
    Link libraries:              Dynamic load

  Python 3:
    Interpreter:                 C:/hostedtoolcache/windows/Python/3.9.13/x64/python.exe (ver 3.9.13)
    Libraries:                   C:/hostedtoolcache/windows/Python/3.9.13/x64/libs/python39.lib (ver 3.9.13)
    Limited API:                 YES (ver 0x03060000)
    numpy:                       C:/hostedtoolcache/windows/Python/3.9.13/x64/lib/site-packages/numpy/_core/include (ver 2.0.0)
    install path:                python/cv2/python-3

  Python (for build):            C:\hostedtoolcache\windows\Python\3.9.13\x64\python.exe

  Java:
    ant:                         NO
    Java:                        YES (ver 1.8.0.412)
    JNI:                         C:/hostedtoolcache/windows/Java_Temurin-Hotspot_jdk/8.0.412-8/x64/include C:/hostedtoolcache/windows/Java_Temurin-Hotspot_jdk/8.0.412-8/x64/include/win32 C:/hostedtoolcache/windows/Java_Temurin-Hotspot_jdk/8.0.412-8/x64/include
    Java wrappers:               NO
    Java tests:                  NO

  Install to:                    D:/a/opencv-python/opencv-python/_skbuild/win-amd64-3.9/cmake-install

Issue submission checklist

• This is not a generic OpenCV usage question (looking for help for coding, other usage questions, homework etc.)
• I have read the README of this repository and understand that this repository provides only an automated build toolchain for OpenCV Python packages (there is no actual OpenCV code here)
• The issue is related to the build scripts in this repository, to the pre-built binaries or is a feature request (such as "please enable this additional dependency")
• I'm using the latest version of opencv-python

[asmorkalov]

Looks like our FFmpeg build does not support the codec and the codec is not installed on your system. Please attach some test video for check. Also you can run the test with the following environment variables to get more details an publish here:

set OPENCV_LOG_LEVEL=DEBUG
set OPENCV_VIDEOIO_DEBUG=1

[Asdts]

hii @asmorkalov I am wondaring can I add an error log which actually throw if the package is not installed or FFmpeg side error which will make it more adaptable.

[nmcdtu]

Dear @asmorkalov,

I've encountered the same issue with opencv-python-headless 4.11.0.86 from conda-forge. Everything functioned properly with version opencv-python-headless 4.10.0.84.

The size of the package for version 4.11 is significantly smaller at 20.7 MB, which is a notable decrease from the 42.8 MB size of version 4.10. This suggests that the codec was not installed as you previously mentioned.

I even installed ffmpeg and x264 suggested here, but it still failed to work.

Package  Version     Build       Size       Kind   Source
x264     1!164.3095  h166bdaf_2  876.5 KiB  conda  x264-1!164.3095-h166bdaf_2.tar.bz2
ffmpeg   6.1.2    gpl_hdfc89ed_706  9.5 MiB  conda  ffmpeg-6.1.2-gpl_hdfc89ed_706.conda

Could you please suggest what I should do? Thank you.

[bradley-e-smith]

So, I just stumbled across this, and I have found that 4.6.0.66 works with rtsp (both windows and wsl) but the exact same program does not work on 4.11.0.86.

I am very new to reporting issues, and if need be can set a a way to (ie python program) to show the issue.

update 4.10.0.84 also works
**update2 with 4.10 works with numpy 1.26.4 and 2.0 -- with 4.11 neither numpy 1.26.4 or 2.0.0 work

[nmcdtu]

@bradley-e-smith please check this issue, it could help you.