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• Create a video from images where the video size is not much larger than the sum of all images

  25 mars 2024, par Stefan Falk

  What I am describing is basically a slideshow.

  


  I was hoping to be able to create a video which consistis of, for example, three different frames 1, 2 and 3 but each of them gets shown for an hour.

  


  Let's say we have a file inputs.txt

  


  file 'img1.jpg'
duration 3600
file 'img2.jpg'
duration 3600
file 'img3.jpg'
duration 3600


  


  I would like to concatenate these images like so :

  


  ffmpeg -f concat -i inputs.txt output.mp4 -y


  


  However, this is already giving me the warning of

  


  


  More than 1000 frames duplicated

  


  


  I have seen some parameters in the documentation like decimate or mpdecimate but they do not seem to do the trick here.

  


  Is it even possible to do what I am trying here ?

  


  It seems like a "no-brainer" to just show a particular image after a certain amount of time but I am not sure how to achieve that.

  


  By the way, I also tried to use MKV here, but this results in a video with just three frames instead of a three hours video :

  


  ffmpeg -f concat -i inputs.txt output.mkv -y


  


• ffmpeg not detecting corrupt video file

  16 février 2018, par Nitishkumar Singh

  I have a video file with duration 2:06:43. The video can be played for 2 hours on vlc player, but as it reaches to 2:03:00 vlc player just skips to the end of duration. I assume reason for this behavior is corrupt video file.

  I am trying to detect error in video file using ffmpeg using below command

  ffmpeg -v error -sseof -60 -i source.mp4 -f null - 2>error.log

  but no error log is generated for video file. is there any way I can detect these errors.

  EDIT
  tried running with warning and it produced below output

  ffmpeg -v warning -sseof -60 -i source.mp4 -f null - 2>error.log

  Finishing stream 0:0 without any data written to it. Finishing stream
  0:1 without any data written to it. Output file is empty, nothing was
  encoded (check -ss / -t / -frames parameters if used)

• What is the most efficient way of stacking two videos using ffmpeg ?

  4 octobre 2024, par technical_difficulty

  I want to stack two videos of a talk together vertically using ffmpeg. One shows the presentation (slides) and one shows the speaker. Since I want to do this for several talks, I'd like to do this in a more general way and as efficiently as possible. Most of the time the videos have different resolutions and aspect ratios.

  


  My current workflow is :

  


  


  1. Scale the video with the lower resolution up to match the resolution of the other video :
ffmpeg -i video1.mp4 -s 1920x1080 -c:a copy video1_upscaled.mp4

     


  


  2. Stack the two videos :
ffmpeg -i video1_scaled.mp4 -i video2.mp4 -filter_complex vstack=inputs=2 combined.mp4

     


  


  


  The videos are between one and two hours long and the commands do take a while to complete. Is there any way of saving some time ?

  


  Would it be faster to put black bars/borders around the smaller video instead of scaling it to the size of the other one ? Can the stacking be done in a more efficient way ? Would it help a lot if those two steps were combined into one ?

  


  Some information that might be relevant :

  


  

  • it's always exactly two videos to stack vertically, one above the other

  


  • the quality of the video is not incredibly important, both having the resolution of the video with the lower resolution would be perfectly fine

  


  • disk space is not an issue

  


  • the resolution and aspect ratio of the videos are known (use any for your example)

  


  • both videos have the same audio

  


  • both videos have the exact same length