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• ffmpeg screencapture with xvfb displaying green screen

  6 novembre 2016, par somya bhargava

  Using xvfb to run a browser window and want to do a screen recording of that Doing

  xvfb-run Firefox http://google.com
  
  ffmpeg -y -r 30 -f x11grab -i :94.0 output.mp4

  Getting output as if colors are washed out

• How to apply the same FFMPEG slide transition for every slide in a sequence ?

  28 juillet 2024, par will

  I have an ffmpeg command to create an MP4 video from a sequence of N x JPEG slides. That is, I do not know how many slides there are in the sequence, it is just a directory of JPEG-s.

  


  I'd like to apply a common slide transition for every slide in the sequence. All the examples I've read seem to need to know how many slides there are before the filter is written. The idea is to use one (simple) transition/filter for every slide.

  


  So far the script looks like this :

  


      play_duration="-framerate 1/10"      #   10 seconds for testing

    ffmpeg                                          \
        ${play_duration}                            \
        -pattern_type glob                          \
        -i "./slides/*.jpg"                         \
                                                    \
         -c:v libx264                                \
         -filter_complex                             \
            "pad=ceil(iw/2)*2:ceil(ih/2)*2; fade=out:120:30"         \
                                                    \
        ./Slideshow.mp4


  


  The first filter : "pad=..." is necessary to deal with inconsistiencies in the JPEG input.

  


  My limited appreciation here is that the "fade=out:120:30" filter ought to work if I didn't need to also have the pad= construct.

  


  Example transition examples for I've come across so far — there are a great many variations on the same pattern — all look a lot like this ...

  


      ffmpeg -loop 1 -t 3 -framerate 60 -i image1.jpg -loop 1 -t 3   \
        -framerate 60 -i image2.jpg -loop 1 -t 3 -framerate 60 -i image3.jpg   \
        -filter_complex                                             \
            "[0]scale=1920:1280:force_original_aspect_ratio=decrease,pad=1920:1280:-1:-1[s0]; [1]scale=1920:1280:force_original_aspect_ratio=decrease,pad=1920:1280:-1:-1[s1]; [2]scale=1920:1280:force_original_aspect_ratio=decrease,pad=1920:1280:-1:-1[s2]; [s0][s1]xfade=transition=circleopen:duration=1:offset=2[f0]; [f0][s2]xfade=transition=circleopen:duration=1:offset=4"                 \
        -c:v libx264 -pix_fmt yuv420p                                \
        output.mp4



  


  

  • from : How to Create a Slideshow from Images using FFmpeg, as a representative example.

  


  


  The requirement is to have the same filter/transition which will apply to all slide changes. It sounded so easy at first.

  


• i can not set video duration in Zoom & Pan with Fade In/Out Transition

  4 octobre 2018, par Prashant Godhani

  I am new to ffmpeg. i am doing Zoom & Pan with Fade In/Out Transition on image to make video i used this script, but this is for 4 image and i want to only for single image so i have tried this command :

  ffmpeg -y -loop 1 -i 1.jpg -filter_complex "\
  
  [0:v]setpts=PTS-STARTPTS,scale=w='if(gte(iw/ih,1280/720),-1,1280)':h='if(gte(iw/ih,1280/720),720,-1)',crop=1280:720,setsar=sar=1/1,format=rgba,split=2[stream1out1][stream1out2];\
  
  [stream1out1]trim=duration=1,select=lte(n\,30),split=2[stream1in][stream1out];\
  
  [stream1out2]trim=duration=2,select=lte(n\,60)[stream1];\
  
  [stream1in]fade=t=in:s=0:n=30[stream1fadein];\
  
  [stream1out]fade=t=out:s=0:n=30[stream1fadeout];\
  
  [stream1fadein][stream1][stream1fadeout]concat=n=3:v=1:a=0,scale=1280*5:-1,zoompan=z='min(pzoom+0.002,2)':d=1:x='iw/2-(iw/zoom/2)':s=1280x720 ,format=yuv420p[video]" -map [video] -vsync 2 -async 1 -rc-lookahead 0 -g 0 -profile:v main -level 42 -c:v libx264 -r 30 df.mp4   

  It works fine but it generate 4 second video. So i’m confused about how to set video duration in this command.