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• Overlay video with other video in ffmpeg

  15 août 2018, par user2212461

  I have a short and a long mp4 video. In the long video, I would like to replace the visual with a part of the visual of the short video. Additionally, I would like to keep the audio of the long video throughout.

  The following set of commands work. However the concat and audio replacing seems to add a slight delay to the video, which makes the audio slightly out of sync from the video.

  ffmpeg -ss 0 -i short.mp4 -t 2.0 -vcodec copy -an v1_short.mp4
  
  ffmpeg -ss 0 -i long.mp4 -t 6.0 -vcodec copy -an v1_before.mp4
  
  ffmpeg -ss 8.0 -i v_before.mp4 -vcodec copy -an v1_after.mp4.mp4
  
  ffmpeg -i v1_before.mp4 -i v1_short.mp4 -i v1_after.mp4 -filter_complex "[0:v] [1:v] [2:v] concat=n=3:v=1 [v]" -map "[v]" out_temp.mp4
  
  ffmpeg -i long.mp4 -i out_temp.mp4 -c copy -map 0:v -map 1:a out_final.mp4

  How can I do this without the audio getting out of sync ?

  I am using ffmpeg version 4.0.2.

• Remove video noise from video with ffmpeg without producing blur / scale down effect

  17 avril 2024, par Sucahyo Aji

  My videos are 1920x1080 recorded with high ISO (3200) using smartphone (to get bright view, backlight scene mode). It produce a lot of noise. I try many video filter but all of them produce blur similar to when we reduce the resolution in half then increase it back again.

  


  Is there a good video noise filter that only remove noise without producing blur ?

  


  Because if it produce blur, I would prefer to not do any filtering at all.

  


  I have tried video filter :

  


  


  • nlmeans=s=30:r=3:p=1

    


  


  • vaguedenoiser=threshold=22:percent=100:nsteps=4

    


  


  • owdenoise=8:6:6

    


  


  • hqdn3d=100:0:50:0

    


  


  • bm3d=sigma=30:block=4:bstep=8:group=1:range=8:mstep=64:thmse=0:hdthr=5:estim=basic:planes=1

    


  


  • dctdnoiz=sigma=30:n=4

    


  


  • fftdnoiz=30:1:6:0.8

    


  


  


  All produce blur, some even worse. I have to use strong setting to make the noise moderately removed. I end up halving the resolution and use remove grain then scale it up again. This is much better for me than all the above method (pp filter is used to reduce size without reducing image detail) :

  


  

  • scale=960:540,removegrain=3:0:0:0,pp=dr/fq|8,scale=1920:1080

  


  


  code example

  


  FOR %%G IN (*.jpg) DO "ffmpeg.exe" -y -i "%%G"  -vf "nlmeans=s=30:r=3:p=1" -qmin 1 -qmax 1 -q:v 1   "%%G.jpg"

  


  Part of the image
  
The image:

  


• Overlay a 16/9 video to a 9/16 ratio and shrink the original video [closed]

  6 avril 2024, par thanhbo

  I assume the video has an aspect ratio of 16/9 (size 1920:1080). I want to convert it to 9/16 ratio and shrink the original video. The formula I wrote is as follows but there is an error. I hope someone can help, thank you.

  


  ffmpeg -y -i A1.mp4 -filter_complex "split[crp0][crp1];[crp0]scale=iw:2*trunc(iw*16/18),boxblur=luma_radius=min(h\,w)/20:luma_power=1:chroma_radius=min(cw\,ch)/20:chroma_power=11,setsar=1[bg],[1:v]scale=(iw-100):-1[bg2];[bg][bg2]overlay=(W-w)/2:(H-h)/2[bg3]" -map "[bg3]" bg3.mp4

ffmpeg -y -i A1.mp4 -filter_complex "split[crp0][crp1];[crp0]scale=iw:2*trunc(iw*16/18),boxblur=luma_radius=min(h\,w)/20:luma_power=1:chroma_radius=min(cw\,ch)/20:chroma_power=11,setsar=1[bg],[1:v]scale=(iw-100):-1[bg2];[bg][bg2]overlay=(W-w)/2:(H-h)/2[bg3]" -map "[bg3]" bg3.mp4