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• Create video with correct FPS from video with incorrect FPS and file containing timestamps for each frame using FFMPEG

  4 février 2023, par Bojan

  I have a video file captured from web camera and using OpenCV in python. The nominal FPS of the web cam is 30 FPS, but because of the environment, the actual FPS varies and sometimes can go as low as 24 fps. The recorded video is created using OpenCV's VideoWriter, using MP4V FOURCC and always has FPS value of 30, which makes the video's duration incorrect if the actual FPS was not 30. I have a file which contains the timestamps when each frame from the web cam was read (generated using python's time.time()).

  


  Question :
  
Using FFMPEG (or other software) can I use the timestamps information to create new video file (probably VFR file) and then convert it to CFR file ?

  


  I am not sure what is the correct approach to create video file with correct time base.
Maybe I can split the video's frames and save them as images and then use the timestamps and the images to create VFR video, but I want to see if it is possible to do this in another, more elegant way.

  


  Thanks in advance !

  


• How to identify users in video file when streaming video ? [on hold]

  24 octobre 2017, par blackjak231

  I’m trying to find a solution to "secure" online video courses on a video streaming platform. The goals are the following :

  • Prevent easy download of video - OK
  • Be able to identify which connected user downloaded the video if it happens - NOK

  The server will be a Debian machine running PHP 7 and the "encryption" of the video will be done "on the stream" for each user.

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  My question is for the second point. I’m unable to find a good solution for it. Here is what i thought of so far and the downsides :

  1. Add a watermark with the user’s name/email with "ffmpeg" on the whole video (in a corner)
     • Can be blurred and therefore useless
  2. Add an invisible digital watermark (inside the video file) with a tool (which i have not found yet)
     • Screen can be recorded and the invisible digital watermark lost.
  3. Add a watermark with the user’s name/email on 2 or 3 specific frames of the video while streaming using "ffmpeg"
     • Best solution from my point of view but no technical solution found so far.

  ---

  Do you have any recommendations on how to do this or a completely different approach to the problem ?

  I’m open to any third party video tool such as Vimeo or any other available.

  Thank you in advance for your help ! :)

• merging audio and video and generating video file .mp4 in android

  17 avril 2015, par Ravind Maurya

  I am merging audio and video using FFMPEG library via grabber and recorder. But out file (*.mp4) got some noise or zic jac sound while I am playing. Please help me If you have any idea how remove the zic jac sound in merged video.