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• ffmpeg image scroll based on size and zoom particular position

  12 décembre 2015, par Lali

  Is it possible to create a video using FFMPEG where it should look like as if we are scrolling the page and zoomin particular location. I don’t have correct example but you can check this video http://avideos.5min.com//9/5193009/519300834_2.mp4 where the first google page scroll effect and along with that i need zoomin option as well.

  If i use the below code it just zoomin but i need scroll and zoomin (vise versa as well)

  ffmpeg -r 45 -i 1.png -vf "zoompan=z='min(zoom+0.0015,1.5)':d=335" -shortest  -pix_fmt yuv420p video1.mp4

• remuxing audio and videos (screen and presenter) captured at the same time does not synchronize

  22 septembre 2014, par user28163

  trying to merge a screencast with a video (without sound) and a sound steam which has been captured separately using ffmpeg using a bash command. All the stream-capture were started at the same time and all ffmpeg processes killed at the same time (pkill). But when I remux them together, the screencast and video does not match, and thus sound does not synchronize either.

  Where did I go wrong ? Any inputs appreciated from ffmpeg experts here. Thanks in advance.

  Please find the ffmpeg output as follows :

  1. The ffmpeg log of two videos muxing (http://pastebin.com/XwnDSf5i)
  2. The ffmpeg log of remuxing the sound with the side-by side video as of 1 above (cannot paste as the pastebin limit exeeded :( ).

  UPDATE :

  After checking the lenght of the screencast, I figured out that the screen capture (though started and stopped at the same time as video and sound using a bash script), is shorter in lenght by 1m54s than video and audio (former 34:22 vs later 36:16). The video was captured in h264 mp4 wrapper at -r 30. So is screen capture but lossless

  %ffmpeg -report -f x11grab -r 30 -s 1920x1080 -i :0.0 -qscale 0 -vcodec libx264 -threads 4 screen.m4v

  Could that be the reason for the delay ? Is there any way to extend the screencast against the videos ? Thanks !

• Creating an MP4 video with ffmpeg from timestamped JPEG frames received by pipe

  16 août 2024, par Denis Fevralev

  I need to create a video with following conditions :

  


  

  1. It can only be made from a sequence of JPEG files, each having its timestamp (milliseconds) in the name. The images' durations are not the same, they differ, so i cannot just concat them all and use particular fps

  


  2. There are several tar archives with the images sequences, the archives are kind of huge so I read them from a file storage as an async steam of data and cannot save them on the disk as files. The frames are read and right away put to ffmpeg running process stdin.

  


  3. The images may have different aspect ratios so it's required to make a NxN square and scale the images to fit in with filling the empty space with pads

  


  


  My current solution :

  


  ffmpeg -r $someFpsValue -i - -vf scale=w=$w:h=$h:force_original_aspect_ratio=1,pad=$w:$h:(((ow-iw)/2)):(((oh-ih)/2)) result.mp4


  


  As you can see, it doesn't let me concat the images with correct durations. I know that the concat demuxer can solve the problem of merging images with different durations but seemingly it doesn't work with pipe protocol. I have an idea of evaluating an average fps as (videoFramesCount) / (videoDurationInSeconds) for -r argument, or maybe even counting the fps for each video's second and then getting the avg, but maybe there is a more reliable solution (like some concat demuxer analogue) ?

  


  Thanks in advance :)