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• Update Grunt install instructions

  22 mars 2013, par nschonni

  Update Grunt install instructions
  The grunt package is no longer installed globally. The global runner has moved to the CLI package with Grunt in the local node_modules folder.
  

• VideoWriter do not write anything

  29 avril 2015, par Nelson

  When I try to use VideoWriter to write a frame it does not work. I already tried lots of FOURCC codes, like the defaul, h264, mjpg, divx, xvid, etc. And yes, I have installed ffmpeg with all the necessary configurations (—enable-shared, —enable-libx264, ...) and the opencv installation is with ffmpeg support on.

  I already google it a lot and everything that I found do not even nearly solve this problem, that is recurrent in OpenCV. The code is the simplest possible, and it worked a few weeks back, but not it does not.

  A few insights : get(CV_CAP_PROP_FPS) returns the unknown option message, with the -1 value (the same happens for the set). The following part of the cmake process of opencv is also interesting :

  -- Could NOT find Jasper (missing:  JASPER_LIBRARIES JASPER_INCLUDE_DIR) 
  
  -- checking for module 'gstreamer-video-1.0'
  
  --   package 'gstreamer-video-1.0' not found
  
  -- checking for module 'gstreamer-app-1.0'
  
  --   package 'gstreamer-app-1.0' not found
  
  -- checking for module 'gstreamer-riff-1.0'
  
  --   package 'gstreamer-riff-1.0' not found
  
  -- checking for module 'gstreamer-pbutils-1.0'
  
  --   package 'gstreamer-pbutils-1.0' not found
  
  -- checking for module 'gstreamer-base-0.10'
  
  --   package 'gstreamer-base-0.10' not found
  
  -- checking for module 'gstreamer-video-0.10'
  
  --   package 'gstreamer-video-0.10' not found
  
  -- checking for module 'gstreamer-app-0.10'
  
  --   package 'gstreamer-app-0.10' not found
  
  -- checking for module 'gstreamer-riff-0.10'
  
  --   package 'gstreamer-riff-0.10' not found
  
  -- checking for module 'gstreamer-pbutils-0.10'
  
  --   package 'gstreamer-pbutils-0.10' not found
  
  -- Looking for linux/videodev.h
  
  -- Looking for linux/videodev.h - not found
  
  -- Looking for linux/videodev2.h
  
  -- Looking for linux/videodev2.h - found
  
  -- Looking for sys/videoio.h
  
  -- Looking for sys/videoio.h - not found
  
  -- Looking for libavformat/avformat.h
  
  -- Looking for libavformat/avformat.h - found
  
  -- Looking for ffmpeg/avformat.h
  
  -- Looking for ffmpeg/avformat.h - not found

  Opencv 2.4.10
  Ubuntu 14.04

  EDIT : I found out that the problem is that the VideoWriter object isn’t open, even after the constructor call :

  VideoWriter wr(outputFile, CV_FOURCC('D','I','V','X'), capture.get(CV_CAP_PROP_FPS,Size(capture.get(CV_CAP_PROP_FRAME_WIDTH),capture.get(CV_CAP_PROP_FRAME_HEIGHT)));

  And using the CV_CAP_PROP_FPS makes OpenCV show the following message in secution time :

  HIGHGUI ERROR: V4L2: Unable to get property <unknown property="property" string="string">(5) - Invalid argument
  
  </unknown>

  Why this hqppen, how can I fix that ?

• How external libraries install for ffmpeg_kit_flutter ?

  8 septembre 2022, par DNB5brims

  I would like to use the h264 package :
https://pub.dev/packages/ffmpeg_kit_flutter

  


  But it just say : "you need to install a package with x264 inside. ", but how ? What is the actual step for it ?