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• Ffmpeg : Move a slider "image" over a "background" from 0% to 100% in sync with the audio

  7 février 2014, par Znuff

  I'm trying to create a video using the follwing code :

  `$`ffmpeg -loop 1 -r 5 -i video.png -r 5 -i progress.png -filter_complex "overlay=x='if(gte(t,0), -W+(t)*5, NAN)':y=H-h" -i video.mp3 -acodec copy video.mp4

  I have the following files

  • video.png
    • this is a 1280x720 px still frame that is simply a background with a waveform of the video.mp3 file
  • progress.png
    • this is simply a 1280x100 px semi-transparent image that should simulate an animation (from from 0 to 100% of the width of the video.png file, in order to simulate "fill up" animation.

  My issues are as following :

  • The video is not in sync with the audio. The progress bar is way off, instead of finishing at the end of the song, it just keeps going on and on and on and on...
  • Also... it just keeps going on and on ! I left it create a 1 hour video and it never stopped.

  I know I'm missing something in the filter, but I have no idea how I could fix it.

  Could someone lend me some help ?

• doc/examples : Always open files as "binary", not "text".

  25 juin 2020, par Carl Eugen Hoyos

  doc/examples : Always open files as "binary", not "text".
  Fixes ticket #8638.
  

  • [DH] doc/examples/decode_video.c
  • [DH] doc/examples/hw_decode.c

• FFMPEG : extracting jpegs at 1 fps rate with "-r 1" or "vf fps=fps=1" causes first three frames to be wrong [closed]

  11 avril 2013, par Stefan

  I need to use ffmpeg to extract video stills from a video, one picture per second, starting with second 0. I created a 4min test video with a running timecode (25fps, starting with 00:00:00 running to 03:59:24) If I use either

  ffmpeg -i input.mp4 -f image2 -r 1 still-%d.jpeg

  or

  ffmpeg -i input.mp4 -f image2 -vf fps="fps=1" still-%d.jpeg

  I fail because the first three images do not display expected time codes 00:00:00, 00:01:00, 00:02:00, but 00:00:00, 00:00:01, 00:00:13, and all subsequent images show having frame 13 in their timecode (and not :00). This causes my video preview to be off by 1-2 seconds.

  I had to resort to invoke ffmpeg for each frame, using -ss 0..240 and -vframes 1 to extract exactly one frame at the exact time. This works perfectly, all output files show the timecode of the first frame of that second.

  This method is considerably slower, however, and I'd rather not use it.

  Is there something I missed with the -r option or fps filter ? I tried specifying fps=fps=1:round=zero, but I got an error saying that the key "round" was not found.

  Thank you in advance !