Recherche avancée

Sur d’autres sites (7487)

• OpenCV video writing to named pipe

  21 janvier 2012, par user28667

  I'm trying to send videos created with OpenCV in real-time to user though Apache (user downloads video from a website). I don't need streaming video. I'm just trying to transfer whole video file. My OpenCV program writes video to a named pipe (created with mkfifo) and PHP scrpt reads from it and outputs to user.

  The problem is that pipe-transfered videos doesn't open in Windows. They're shorter exactly at 7072 bytes (checked with different videos). They are not just truncated. The first difference between videos appeared in 5-th byte. And there is no mistake in PHP script. I've checked it using :

  cat fifo.avi > output.avi

  The result was the same. How to make OpenCV write videos to pipes just as to normal files ? Why this happens ? Or is there another way to send videos in real-time to user ?

  P. S. Thanks and sorry for bad English
  P. P. S. I'm creating CvVideoWriter with this code if it matters :

  cvCreateVideoWriter("fifo.avi",CV_FOURCC('M','J','P','G'),25,cvSize(blah blah blah),1)

• Getting the frame pkt_pts from ffmpeg

  2 février 2018, par kama

  I record a stream similar to this (but I pipe the image to stdout and process the frames in real time) :

  ffmpeg -debug_ts -y -i http://my_stream.com -strict -2 out.mp4

  Now I need to map my frames to the pkt_pts. This pkt_pts I can get by running :

  ffprobe -i http://my_stream.com -show_frames -select_streams v:0

  Although starting ffprobe is not an option since I need to excactly know which pkt_pts belongs to what frame.
  Therefore I’m using the -debug_ts in my ffmpeg call, which gives me a lot of output to stderr, which I then parse out. The only output line which matches the number of frames is the one which starts with : muxer <- type:video This line does contain a pkt_pts, but it always starts with 0 (not the global pkt_pts).

  Is there a way to map a frame, to the global pkt_pts in real time with ffmpeg ?

• FFmpeg start after reboot

  11 avril 2018, par Paciorek Radek

  A got a question.
  I want to start a process like ffmpeg after reboot.
  How to do this ?

  I trying to use ’nohup ffmpeg .... -y’ in root crontab.

  from crontab :

  @reboot /usr/bin/nohup /usr/local/bin/ffmpeg -i 'rtsp://login:p
  
  ass@192.168.1.10:554/mode=real&idc=1&ids=2' -vf fps=1 -update 1 /var/www/html/img.jpg -y 

  This dosent work so i try this.

  I make .sh script like this :

  #!/bin/bash
  
  
  
  /usr/bin/nohup /usr/local/bin/ffmpeg -i 'rtsp://login:pass@192.168.1.10:554/mode=real&idc=1&ids=2' -vf fps=1 -update 1 /var/www/html/img.jpg -y 

  and add this to crontab
  @reboot /home/.../script.sh

  Also script is executable.
  It working fine when i try to run as root or with sudo.

  Nothing seems to working after reboot automatycally.

  How to make this working ?
  Thank you in advanced.