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• 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++

  


• ffmpeg getting syntax error when run inside shell script only.. Why ? [duplicate]

  10 décembre 2017, par bmck2006

  This question already has an answer here :

  • Unexpected ’(’ in bash [duplicate]
    
    2 answers
    

  OS : Raspbian

  I’m currently working on a bash script that will merge all .AVI videos in the current directory, to one .AVI file. I’ve found the following to work perfectly for me, when run directly in the terminal :

  ffmpeg -f concat -safe 0 -i <(find . -name '*.avi' -printf "file '$PWD/%p'\n") -c copy "$(date -d '-1 day' +'%F')".avi

  This works perfectly, and I find a new .AVI file listed in the current directory (with a date name from yesterday).

  Now, when I add this same command to my script (merge.sh), I get the following output :

  /home/pi/Documents/MotionScripts/merge.sh: 11: 
  
  /home/pi/Documents/MotionScripts/merge.sh: Syntax error: "(" unexpected

  This is beyond frustrating. And yes, ffmpeg command from earlier is on line 11. The script navigates to the correct directory where the multiple .avi files are stored.

  Here is the entire script :

  #!/bin/bash
  
  
  
  #This script combines multiple AVI files within the current directory, into one long video
  
  
  
  cd /media/myBook/Security/yesterday
  
  
  
  sudo mv * /home/pi/Videos/tempconversion
  
  
  
  cd /home/pi/Videos/tempconversion
  
  
  
  ffmpeg -f concat -safe 0 -i <(find . -name '*.avi' -printf "file '$PWD/%p'\n") -c copy "$(date -d '-1 day' +'%F')".avi
  
  
  
  sudo mv "$(date -d '-1 day' +'%F')".avi /media/myBook/Security/yesterday
  
  
  
  sudo rm -f *

  Why am I getting the syntax error only when the same command is being issued within an executable script ?

  RESOLVED ! Shouldn’t have used ’sh’ to run the script. Make sure the script is executable (sudo chmod +x merge.sh) and run by entering the full path.