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• What it the expected behavior when using the input Framerate option (in FFmpeg) when the input is a real-time camera device ?

  28 août 2023, par J.M.

  As far as I know, the use of the Framerate option should be used only on an input files (like sequence of images or perhaps a video file that don't have a defined PTS).

  



  However, if I run the command below on my web-cam, the video still streams fine (at least for a few hours from what I've checked till now). Why is that still works ? Should I expect that something will get wrong ? (maybe later, after a few hours or days of streaming)

  



  ffmpeg -framerate 30 -f v4l2 -copyts -i /dev/video0 -c:v libx264 -r 30 -f mpegts udp://192.168.10.199:1234


  



  EDIT :

  



  After running some more tests, it seems that when I'm running the command like this, the steam get stuck after a few hours :

  



  ffmpeg -framerate 30 -f v4l2 -copyts -i /dev/video0 -c:v libx264 -r 30 -f mpegts udp://192.168.10.199:1234


  



  However, if I run the command like this, it runs for days :

  



  ffmpeg -r 30 -f v4l2 -copyts -i /dev/video0 -c:v libx264 -r 30 -f mpegts udp://192.168.10.199:1234


  



  But I don't understand why...

  


• FFmpeg Video Library Quick Review

  3 juillet 2019, par Rich_F

  I’m in need of reducing 18 videos so I can review them daily. I’d like to script some kind of compression or sampling using FFmpeg to not have to sit through 6 hours of video every day.

  What is the best way to review 6 hours of videos captured every day on SD cards ? The videos come in two cards, a 32 GB card ( 4 hours) and a 16 GB card ( 2 hours).

  Currently, I’m concatenating all videos and creating a screenshot every 3 seconds, which seems the longest I can go without missing something in the field of view (a vehicle will enter/leave). Still, this is thousands of images per card, and I select all, then preview and scroll down using page up/down. Any vehicle quickly appears in the thumbnails. This system isn’t bad, but I’m always inquisitive. I’m looking for more ways of sampling or seeing if any motion detection or frame analysis might register where I should be looking in my library of original captured videos.

  Options :

  1. Motion capture by analysis of frame by frame through trial and error on sensitivity to not measure wind on the bushes. This could be output to filename and time within the video (videos are captured 10 minutes long).

  2. Take my exported list of png files and string them together somehow into a slide show.

  3. Version 1 here, plus some retroactive capture of clips inside master clips.

  4. Some kind of compression. Again, I have to respect the 3-second max jump.

  Any other options that would be relatively easy to achieve without moving into any other software ? I’m trying to put the heavy lifting on the computer, as staring at videos is not something I’m finding I’ll be able to do for many days.

• How to use FFmpeg

  20 septembre 2021, par Moayyad Yaghi

  I'm trying to extract frames from a video and I've picked ffmpeg ( tell me if you know something better ) for this task.

  


  I've downloaded its source and don't know how to use it ?? how can I compile it ?

  


  What is the recommended language for it ? I know Python and C++.
Please note that my operating system is Windows Vista 64 bit .