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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 !

  


• Revision 29902 : - mise à jour de l’appel des #SAISIE (celles qui risquent un plantage en ...

  16 juillet 2009, par marcimat@… — Log

   mise à jour de l’appel des #SAISIE (celles qui risquent un plantage en priorité)
   mise à jour du plugin.xml

• ffmpeg - problem in copying the stream with timed metadata during a split command

  15 novembre 2020, par Swarna Ananthan

  I am facing a problem while copying mp4 along with the data stream in a split command.

  


  ffmpeg -i 'testinput.mp4' -map 0 -copy_unknown -ss 12.800000 -t 14.549 -c copy testoutput.mp4


  


  I am getting the below error.

  


  Duration: 00:04:45.25, start: 0.000000, bitrate: 120 kb/s
    Stream #0:0(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 116 kb/s (default)
    Metadata:
      creation_time   : 2020-05-26T20:58:03.000000Z
      handler_name    : WowzaStreamingEngine
    Stream #0:1(eng): Data: none (amf0 / 0x30666D61), 1 kb/s (default)
    Metadata:
      creation_time   : 2020-05-26T20:58:03.000000Z
      handler_name    : WowzaStreamingEngine

File 'testoutput.mp4' already exists. Overwrite? [y/N] y

[mp4 @ 0x7fe8b0808800] Could not find tag for codec none in stream #1, codec not currently supported in container
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
Stream mapping:
  
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
Last message repeated 1 time


  


  Stream#1 is datastream in my case.