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• Use FFMPEG to Save Live CCTV Video Streams that Has Wrong FPS Encoded, Published by Video Clips instead of Frames, and With Nonnegligible Frame Loss

  6 mars 2023, par Crear

  I want to use FFMPEG command line to archive live CCTV video stream (no audio) from Newark Citizen Virtual Patrol (https://cvp.newarkpublicsafety.org) for traffic analysis, previously I was using (I'm just a noob in these commands)
os.system('ffmpeg -t 24:00:00 -i '+address+' -hide_banner -c:v copy -s 640x360 -segment_time 00:15:00 -f segment -strftime 1 -reset_timestamps 1 "'+OutPath+camera_location+'_%Y-%m-%d-%H-%M-%S.mp4"') to archive the videos everyday and segment them into 15-min-long videos.

  


  However, there are several issues.

  


  

  1. The FPS read from the video stream is actually slower than it really is. For example, it's actually 12, but the decoded result says 8, so every time it generates a 15-min-long video, it only pasts 10 11 mins in the real world.

  


  2. Due to unstable frame loss, the FPS is not a stable value either. Therefore, when I manually set the FPS, it usually make the video has wrong length, and sometimes when the stream froze, it keeps waiting because it hasn't finished 15-min-long video. Something I noticed is that it may generate a 15-min-long video, which contains both night and day, started from perhaps 2AM but ended at 8AM.

  


  3. The live CCTV video stream is not frame by frame, but video clip by video clip. Therefore, when I set the -use_wallclock_as_timestamps to 1, the video will be ultra-fast playing the short video clip, then frozen for the rest of time until receiving next video clip.

  


  


  The only thing I can think of is to re-distribute the frames evenly between the timestamp of receiving the current video clip and the timestamp of receiving the prior video clip. What parameters can help FFMPEG to fix the FPS and archive correctly ? I am using FFMPEG to save the video instead of using OpenCV to decode the frame and then encode a video because we have huge amounts of cameras and our legacy Xeon processor had trouble encoding so many frames simultaneously.

  


  Any suggestion is appreciated !

  


• ffmpeg : How can I add video-1 at the beginning of video-2

  10 juin 2012, par Crazy_Bash

  I want to add video-1 at the beginning of video-2 with command line in linux, is it possible ?

• how to convert a video to H264 video codec format & webm and ogv with watermark via ffmpeg

  5 mars 2015, par ali

  I used this code :

  function convert()
  
  {
  
    exec("$ffmpegPath  -i $inputPath -i $watermark -filter_complex overlay=10:10 $outPath");
  
  }
  
  
  
  convert('test.mp4');
  
  convert('test.webm');
  
  convert('test.ogv');

  This code works...but not in browser !
  I can run output videos via KMPLAYER in desktop (ovg only video - no audio)

  I want to run it on web via videojs.

  mp4 playback with videojs in browsers - audio plays but video is blank.

  I googled and I think I must convert it to h264 format...

  Can somebody change my orginal code to 3 valid codes for h264,webm and ogv ?