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• does the ffmpeg overlay filter support a fade option ?

  2 décembre 2016, par Stefan

  I need several overlaid image files to fade in/out at different time intervals on a video file using ffmpeg.

  I am aware of the technique some people use to achieve the effect i’m looking for, which looks something like this :

  ffmpeg.exe -i in_video.mov -loop 1 -i image.png
  
  -filter_complex "
  
  [1:v]fade=in:st=2:d=0.5:alpha=1,fade=out:st=4:d=0.5:alpha=1[t0];
  
  [1:v]fade=in:st=8.6:d=0.5:alpha=1,fade=out:st=12.6:d=0.5:alpha=1[t1];
  
  [1:v]fade=in:st=12.2:d=0.5:alpha=1,fade=out:st=14.2:d=0.5:alpha=1[t2];
  
  [0:v][t0]overlay=shortest=1[tmp0];
  
  [tmp0][t1]overlay=shortest=1[tmp1];
  
  [tmp1][t2]overlay=shortest=1[tmp2]"
  
  -map "[tmp2]" out_video.mov

  But i experience linear performance decreases as I tack on more overlays.

  By leveraging the ’enable’ overlay option like so I can achieve great performance but lose the ability to fade :

  ffmpeg.exe
  
  -i in_video.mov
  
  -i image.png
  
  -filter_complex "
  
  [0:v][t0] overlay=enable='between(t,2,4.5)' [tmp0];
  
  [tmp0][t0] overlay=enable='between(t,8.6,13.1)' [tmp1];
  
  [tmp1][t0] overlay=enable='between(t,17.3,21.5)' [tmp2]"
  
  -map "[tmp2]" output_video.mov 

  Can i tack on a ’fade’ option along with the ’enable’ option to optimize performance ? Or should i just attempt to contribute a new option for the overlay filter to the open source ?

• FFmpeg cannot extract correct first frame - always extract the second frame [closed]

  21 octobre 2024, par Cai Yu

  I am on macos Ventura 13.2.1, on Macbook Pro M1Max.

  


  The video is number counting animation video. From 2 to 125. The number on first frame is 2. The number on last frame is 125. The number plus one on each frame. You can download the video here.

  


  NOTE that :
First, you hit space bar to play it in Finder, you can see the first frame of the video is number 2.

  


  Second, in professional Video editing software - davinci resolve, on the timeline, you can see the first frame is number 2.

  


  Now I try to use FFmpeg to extract the first frame of the video.
First Try :

  


  ffmpeg -i /Users/chris/Downloads/2to125.mov -vframes 1 /Users/chris/Downloads/1.png


  


  The output png image is number 3. So it's actually the second frame.

  


  Second try :

  


  ffmpeg -i /Users/chris/Downloads/2to125.mov -frames:v 1 /Users/chris/Downloads/1.png


  


  The output png image is still the second frame - the number 3.

  


  Third try :

  


  ffmpeg -i /Users/chris/Downloads/2to125.mov -vf "select=eq(n\,0)" -q:v 3 /Users/chris/Downloads/1.png


  


  The output image is sitll the wrong second frame.

  


  NOTE that :

  


  first : all these three method are from internet. And a lot of people voted correct answer for this question.

  


  second : all their output on my system is the incorrect second frame, not the first frame.

  


  I cannot find what's wrong. Hope friend here help me.

  


• Open Video Downloader Error : Postprocessing : ffmpeg not found

  11 septembre 2022, par Nick the Community Scientist

  Error Thrown :

  


  ERROR: Postprocessing: ffmpeg not found. Please install or provide the path using --ffmpeg-location


  


  Context : macOS Big Sur M1 Chip, using the open video downloader program GitHub release or Homebrew. This specifically was thrown at the end of downloading the video file and the audio file from a given URL. The two files remained separate as a result of the error, the video was playable normally, but audio was in a .webm format (unusable for most people).

  


  Analysis : It is clear that a dependency is missing, or its path cannot be located. For macOS users like me, the first step after checking the app's preferences for a path set or dependency download function is to check for the given dependency in the system. Once checking using Homebrew, it became clear that several dependencies were missing.