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• ffmpeg : Is there a way to create video from images and overlay on image at same time ?

  2 mai 2019, par sarkon

  I am trying to create a video from still images using ffmpeg. The command I use to do this is

  ffmpeg -y -r 3 -i input_images%03d.png -c:v libx264 -vf fps=24 -pix_fmt yuv420p output.mp4

  However, I would like to overlay this video on still image, without creating a video of the still image first. So, for example, if I have the following images

  [still, frame1, frame2, frame3]

  I’d like a command to create a video of frame1, frame2, and frame3 overlayed on still.

  all with one command. Is there a way to do this ?

  I’ve looked at several answers to related problems (e.g., Add image overlay on video FFmpeg) but they don’t answer my question, exactly.

• Extract frame at x time and crop [duplicate]

  31 mars 2019, par Thaison Nguyen

  This question already has an answer here :

  • FFmpeg stucks for few seconds on start
    
    1 answer
    

  I use the following cmd line to extract a frame at a certain timestamp and crop the image for analysis

  ffmpeg -i nba2.mp4 -ss 00:00:02 -vf "crop=in_w:in_h/6:0:in_h*.85" -vframes 1 out.png

  I get it just fine at 2 seconds, but the farther I go out, the longer it takes. It takes over 1 minute to extract a frame at 14 minutes and 30 seconds (00:14:30).

  ffmpeg -i nba2.mp4 -ss 00:14:30 -vf "crop=in_w:in_h/6:0:in_h*.85" -vframes 1 out.png

  This is a HD video, it appears that FFMPEG is looping through each frame to get to 00:14:30, is there a way to improve this efficiency ?

• How to extract time-accurate video segments with ffmpeg ?

  30 octobre 2023, par Jim Miller

  This is not a particularly new question area around here, but I've tried what's been suggested there without much luck. So, my story :

  


  I've got a hunk of 15 seconds of straight-from-the-camera.mov video out of which I want to extract a specific chunk, which I can identify by start time and stop time, in seconds. I started by trying to do what I'll call a "copy extraction" : to get seconds 9 to 12,

  


  ffmpeg -i test.mov -vcodec copy -acodec copy -ss 9 -to 12 test-copy.mov


  


  This was a not-bad start, but there are some black frames at the beginning and end of the clip, which I can't have — it has to be a clean edit from the original. So, I tried recoding the original into a new, trimmed clip :

  


  ffmpeg -i test.mov -ss 00:00:09 -t 00:00:03 test-out.mov


  


  This is better, but not quite : There are no longer any black frames at the beginning of the clip, but they're still there at the end.

  


  After some more browsing and reading, I then suspected that the problem is that ffmpeg is having trouble finding the proper points because of a lack of keyframes in the original video. So I recoded the original video to (presumably) add keyframes, in a couple of different ways. Since I want to be able to pick video at boundaries of a second ("from 9 seconds to 12 seconds"), I tried, copying various suggestions around the web,

  


  ffmpeg -i test.mov -force_key_frames "expr:gte(t, n_forced)" test-forced.mp4


  


  and

  


  ffmpeg -i test.mov -g 1 test-g-inserted.mp4


  


  (I built these as mp4's based on some comments about an mp4 container being needed to support the keyframe search, but I'm honestly just hacking here.) I then tried the extraction as before, but on these new videos that presumably now have keyframes in them. No luck — both seem to be about the same ; the start is OK but there are still black frames at the end. (FWIW, both test-forced.mp4 and test-g-inserted.mp4 also have trailing black frames.)

  


  So : I'm still stuck, and would like to not be. Any insights out there as to what I'm doing wrong ? I feel like I'm close, but I really need to get rid of those trailing black frames....