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• Construct fictitious P-frames from just I-frames [closed]

  25 juillet 2024, par nilgirian

  Some context.. I saw this video recently https://youtu.be/zXTpASSd9xE?si=5alGvZ_e13w0Ahmb it's a continuous zoom into a fractal.

  


  I've been thinking a whole lot of how did they created this video 9 years ago ? The problem is that these frames are mathematically intensive to calculate back then and today still fairly really hard now.

  


  He states in the video it took him 33 hours to generate 1 keyframe.

  


  I was wondering how I would replicate that work. I know by brute force I can generate several images files (essentially each image would be an I-frame) and then ask ffmpeg to compress it into mp4 (where it will convert most of those images into P-frames). I know that. But if I did it that way I calculated it'd take me 6.5 years to render that 9min video (at 30fps, 9 years ago).

  


  So I imagine he only generated I-frames to cut down on time. And then this person somehow created fictitious P-frames in-between. Given that frame-to-frame are similar this seems like it should be doable since you're just zooming in. If he only generated just the I-frames at every 1 second (at 30fps) that work could be cut down to just 82 days.

  


  So if I only want to generate the images that will be used as I-frames could ffmpeg or some other program just automatically make a best guess to generate fictitious P-frames for me ?

  


• FFMPEG zoompan filter cut short my video and slowed it down [on hold]

  9 décembre 2018, par Ewan Sou

  I am using FFMPEG (version 4.0.2) to zoompan my video. My code is as below

  ffmpeg -y -i input.mp4 -loop 1 -i overlay.png -ss 0 -t 10 -filter_complex "[0:v]scale=iw+iw:ih+ih, zoompan=z='if(lte(pzoom,1.0),1.6,max(1.001,pzoom-0.004))':d=1:x='iw/2-(iw/zoom/2)':y='0':s=720x720, setsar=1 [v0];[1:v]crop=720:720,fade=t=in:st=0:d=1,fade=t=out:st=3:d=1[v1];[v0][v1] overlay [v]" -map "[v]" -f mp4 -preset ultrafast -y output.mp4

  Essentially, what this code should do is slowly pan out from the center of my video, with a logo (overlay.png) fading in and out.

  This input.mp4 is 10 seconds. With the above code, the final video duration is 10 seconds still. But its not the full footage, it is cut short and compensated with slow motion to make it 10 seconds still...

  I need the final video to not be cut off at all. It should be the full footage and no slow motion effect.

  Anyone has any ideas what I am doing wrong ?

  Input video is at : https://instantly.sg/photobooth/input.mp4

  Overlay is at : here

  Thanks in advance !

• Issues with ffmpeg2theora- Please port your application to avcodec_decode_audio4()

  8 août 2016, par sudheerpaturi

  I am using the latest versions of ffmpeg and ffmpeg2theora for windows. I try to convert an mp4 file(with audio) to an ogv file using this command on terminal

  ffmpeg2theora.exe -v 10 input_file_name.mp4

  Then its giving out this error.
  Image for the Output

  I am totally new to using this tool. From my investigation I found that this is because of the new versions. This problem doesn’t exist with the old versions.

  Is there any way to get rid of this issue ?

  Thanks in advance.