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• opencv vs live555 vs ffmpeg for decoding rtsp stream with added metadata ?

  17 août 2021, par Peter Parker

  From an IP camera I must decode a h.264 encoded rtsp transport stream containing a program clock reference (PCR), transmitted in the adaptation field of the TS packet. I am using a Windows machine.

  


  This PCR field is transmitted at least every 100ms.

  


  I need to extract this timestamp data for each frame of the video.

  


  I would also like to use OpenCV to process each frame, whilst acknowledging the current time, based on the PCR field value.

  


  OpenCV is not capable of decoding the live rtsp url AND it discard the ancillary data I need.

  


  Do I need to use live555 along with ffmpeg to decode the stream ? Or is it possible to extract this data using ffmpeg and opencv libraries alone ?

  


  Suppose I embed a SMPTE/MISB compliant Microsecond Timestamp (KLV metadata packet) in the VANC space after achieving this.

  


  Will the same strategy work ?

  


  Thanks in advance for any pointers.

  


• FFMPEG Drag and Drop sh file

  29 avril 2021, par WFCDefi

  On Windows I have a simple batch file which I drop video files onto to convert to webms, it saves a lot of time as I prefer to just use the same configuration and don't care much about the names.

  


  @echo off 
echo. 
ffmpeg -i %1 -c:v libvpx-vp9 -quality good -cpu-used 2 -b:v 5000k -qmin 15 -qmax 45 -maxrate 500k -bufsize 1500k -framerate 60 -threads 8 -vf scale=-1:1080 -c:a libvorbis -b:a 192k -f webm %1.webm 
pause


  


  I know the .bat file won't really work in Linux (I'm on pop os so pretty much Ubuntu) so with the other lines removed and the %1 changed to $1 it works. It won't do anything if I try dragging and dropping a video file onto it though.

  


  I can type sudo then drag and drop the .sh file followed by a video into a terminal and press enter and it will have the same effect as dragging a video file onto a bat file in Windows.

  


  Is there a way to recreate dragging and dropping a file directly onto another and it executing in Linux or is the terminal the only way ?

  


• retriving video details with ffprobe in php

  15 juillet 2014, par Roohbakhsh Masoud

  i’m using this command for retrieve video information in ubuntu terminal :

  ffprobe -show_streams sample.mp4

  this command show all information about video in terminal, but when i use this command in php and use exec function to retrieve result , return

  string(0) ""
  
  {}

  how i can retrieve result in php ?

  my code :

      public function information($ffmpeg,$file)
  
      {
  
        $info = exec("$ffmpeg -show_streams $file");
  
        return $info;
  
      }