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• ffmpeg delay video in overlay

  4 août 2020, par Sam

  I am trying to overlay 2 videos, and one of them (the one on the "bottom"), I want to delay the start of (let's say by 2 seconds).

  


  So, either hold the first frame for the duration of the delay, or have black frames for the duration of the delay. I have no preference as to which.

  


  Here is what I tried based on this similar question : https://superuser.com/questions/734234/delayed-video-overlay-using-ffmpeg

  


  ffmpeg
-i video_top
-i video_bottom
-filter_complex
"[0:v]trim=start='00\:04\:17.8':end='00\:04\:32.8',setpts=PTS-STARTPTS, scale=-1:'ih-ih*.5':eval=frame[v0];
[0:a]atrim=start='00\:04\:17.8':end='00\:04\:32.8',asetpts=PTS-STARTPTS[a0];
[1:v]setpts=PTS-STARTPTS+2/TB, format=yuva420p[v1];
[v1][v0]overlay=y=(main_h-overlay_h)*.074:format=yuv444:shortest=0:alpha='straight',format=yuv420p[out]"
-map [out] -map [a0] -vcodec libx264 testing_14.mp4


  


  However, the result of this is that BOTH videos freeze the first frame for the delayed duration (of 2 seconds in this case). I have tried a bunch of alternative options, including

  


  

  • Only setting PTS on one of the video streams instead of both

  


  • Using -itsoffset instead of PTS

  


  


  Nothing seems to work.

  


• ffmpeg - put video atop of second and center it while keeping aspect ratio

  25 août 2022, par artolini

  I'm trying to put 16:9 video atop of same blurred 1:1 video just like on the photos.
I'm looking a wise guy with ffmpeg knowledge to help me with think of about the command which will :

  


  

  1. rescale 16:9 (sharp video) accordingly to blurred one height (keeping the width automatically to ratio)

  


  2. center the 16:9 (sharp video) to x position = (blurredVideoWidth / 2) - (sharpVideoWidth / 2)

  


  


  My current comment looks like this :

  


  ffmpeg -y -i ${squareBlurredVideoUri} -i ${square169VideoUri} -filter_complex "[1:v]scale=620:-1[v2];[0:v][v2]overlay=0:0" -codec:a copy ${squareFinalVideoUri}

  


  As you can see scale is hardcoded to 620 which is wrong because we should rescale it accordingly to blurred video height.

  


  Overlay is set to 0:0 which places sharp video to x = 0 and y = 0 and should center it

  


  Thank you in advance.

  


  Current result :

Desired result :


  


• ffmpeg error : Unable to find a suitable output format for 'scale=1500:1000'

  13 février 2021, par Tomáš Zato - Reinstate Monica

  I am trying to convert a bunch of images into a video. The original image resolution is 6000x4000, but if I use ffmpeg to create a video with that resolution, no player can even play it because it's way to huge.

  


  I tried to set the output resolution as such, dividing the input resolution by 4 :

  


  ffmpeg -r 60 -s 1500x1000 -start_number 3790 -i DSC_%04d.jpg -vcodec libx264 -crf 25  -pix_fmt yuv420p ../video_lowres.mp4


  


  This had no effect and still produced 6000x4000 video. So instead, I tried this parameter : scale=1500:1000 The full command I ran :

  


  ffmpeg -r 60 scale=1500:1000 -start_number 3790 -i DSC_%04d.jpg -vcodec libx264 -crf 25  -pix_fmt yuv420p ../video_lowres.mp4


  


  But I got this error :

  


  [NULL @ 000002ad897bd9c0] Unable to find a suitable output format for 'scale=1500:1000'
scale=1500:1000: Invalid argument


  


  How can I create a downscaled video from photos using ffmpeg ?