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• How to Add Gstreamer Plugin on Mac when installed from Tutorials

  31 juillet 2014, par Dave Collins

  I basically have two installs of gstreamer on my Mac OS X machine :
  The one that works perfectly was installed following this tutorial (http://docs.gstreamer.com/display/GstSDK/Installing+on+Mac+OS+X) and downloading and installing the Developer SDK and using XCode. All tutorials work well.

  I also have a local version installed with Homebrew but video playback does not work on that version (see SO : gstreamer gst-launch sample mac osx plays audio but not video)

  SO, I’m trying to install the FFMPEG plugin into the working xcode dev system so that I can use FFDEC_H263 in a project.

  I tried simply copying the related .SO files (e.g. libgstffmpg.so) from the homebrew (cellar) location to the

   /Library/Frameworks/GStreamer.Framework/Versions/0.10/lib/gstreamer-0.10/ 

  directory and changing permissions. However, that gives me a "Caught a segmentation fault while loading plugin file" error when building any code.

  I also noticed that in the Xcode directory mentioned above, all of the plugins have a related .a and .la files in the \static subdirectory... Those same files don’t exist in the homebrew version.

  So, what is the proper way to install a plugin when you’ve started with the developer SDK for Mac OSX ?

• Saving Uncompressed Video Files using OpenCv, Gstreamer, and/or FFMPEG ?

  21 septembre 2022, par adav0033

  I have been trying to implement the cv::VideoWriter function from OpenCV to generate a an uncompressed video file. I started this because of a statement within the OpenCV Documentation which I will link here along with the statement.

  


  cv::VideoWriter::VideoWriter    (   const String &  filename,
int     fourcc,
double  fps,
Size    frameSize,
bool    isColor = true 
)       


  


  "If FFMPEG is enabled, using codec=0 ; fps=0 ; you can create an uncompressed (raw) video file."

  


  Ref. https://docs.opencv.org/3.4/dd/d9e/classcv_1_1VideoWriter.html

  


  However whilst troubleshooting the function I came across the refuting statement,

  


  " VideoCapture and VideoWriter do not provide interface to access raw compressed video stream, except maybe MJPEG in some cases.
Make sure you actually use FFmpeg backend by setting apiPreference parameter : VideoWriter("outfile.avi", cv2.CAP_FFMPEG, ...)"

  


  Ref. https://github.com/opencv/opencv/issues/14573

  


  I am now confused about how I go about writing the cv::VideoWriter function to satisfy the requirements to create an uncompressed video file (.avi) and if it is even possible. If it is not possible how do I achieve the outcome of saving an raw uncompressed video file, as I assume it would use some combination of FFMPEG, OpenCV,or Gstreamer.

  


  Note : My code is implemented in c++

  


• Saving Raw Uncompressed Video Files using OpenCv, Gstreamer, and/or FFMPEG ?

  20 septembre 2022, par adav0033

  I have been trying to implement the cv::VideoWriter function from OpenCV to generate a an uncompressed (raw) video file. I started this because of a statement within the OpenCV Documentation which I will link here along with the statement.

  


  cv::VideoWriter::VideoWriter    (   const String &  filename,
int     fourcc,
double  fps,
Size    frameSize,
bool    isColor = true 
)       


  


  "If FFMPEG is enabled, using codec=0 ; fps=0 ; you can create an uncompressed (raw) video file."

  


  Ref. https://docs.opencv.org/3.4/dd/d9e/classcv_1_1VideoWriter.html

  


  However whilst troubleshooting the function I came across the refuting statement,

  


  " VideoCapture and VideoWriter do not provide interface to access raw compressed video stream, except maybe MJPEG in some cases.
Make sure you actually use FFmpeg backend by setting apiPreference parameter : VideoWriter("outfile.avi", cv2.CAP_FFMPEG, ...)"

  


  Ref. https://github.com/opencv/opencv/issues/14573

  


  I am now confused about how I go about writing the cv::VideoWriter function to satisfy the requirements to create a raw uncompressed video file (.avi) and if it is even possible. If it is not possible how do I achieve the outcome of saving an raw uncompressed video file, as I assume it would use some combination of FFMPEG, OpenCV,or Gstreamer.

  


  Note : My code is implemented in c++