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• concat 2 different image size multiple tracks videos

  12 avril 2020, par Mher Mkrtchyan

  I try concat two videos (1.mkv has 640:360 image size, 2.mkv has 1280:720 image size), both videos have 2 video tracks and 0 audio tracks. I tried this code :

  



  ffmpeg -i 1.mkv -i 2.mkv -filter_complex "[0:v:0]scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:(ow-iw)/2:(oh-ih)/2[v0];[0:v:1]scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:(ow-iw)/2:(oh-ih)/2[v0];[v0][1:v:0][1:v:1]concat=n=2:v=2:a=0[v]" -map "[v]" -c:v "libvpx" 1+2.mkv


  



  But I have wrong :

  



  Filter pad has an unconnected output


  


• Append two videos without duplicating FFMPEG

  10 septembre 2021, par Hasindu Lanka

  Let's say we have 2 video files (X,Y) in the same format, codec and dimensions.

  


  X is a longer video with several gigabytes in size. Y is a short 10 second video. I want to append Y to the end of X without creating another copy of X (Because it's big in size)

  


  I have to repeat this process for hours with many 10 second videos arriving one after another.

  


  Currently, I'm concatenating files using ffmpeg.

  


  ffmpeg -f concat -safe 0 -i chunk.list -c copy final-video.mkv

  


  chunk.list contains file names of X and several 10 second videos. After this, X will be deleted and replaced by final-video.mkv. Then, repeat.

  


  But this needs twice the storage capacity and I/O operations. How to do this without creating duplicates ?

  


  It's okay to duplicate these 10 second videos. But duplicating that bigger file X really hurts performance.

  


  Additional info :

  


  All these videos will be encoded with H264, H265, VP8 or VP9 and contained in MKV or MP4 as they are codec copy friendly. Only one of these formats will be used.

  


  This is for a special case screen recorder that's supposed to run on cloud and preemptive remote desktops (Linux).
HTML/JS browser front-end captures the screen and sends to the back-end (Golang) as chunks through HTTP. Network route is undefined and unreliable as there can be firewalls/proxies between the front-end and the back-end. Therefore, we can't use connections like UDP. So the only option is to send video chunks using HTTP.

  


  It's FOSS on https://github.com/HasinduLanka/screencorder

  


• How to overlay 2 videos at different time over another video in single ffmpeg command ?

  17 mars 2018, par Qandeel Abbasi

  Using ffmpeg command line I want to overlay 2 different videos on top of another (main video) at different time for different duration. I have successfully overlayed 1 video over the main video at specific time and for specific duration using following command :

  ffmpeg -i main.mp4 -i first.mp4 \
  
  -filter_complex "[1:v]setpts=PTS-32/TB[a]; \
  
                   [0:v][a]overlay=enable=gte(t\,5):eof_action=pass[out]; \
  
                   [1] scale=480:270 [over]; [0][over] overlay=400:400" \
  
  -map [out] -map 0:a \
  
  -c:v libx264 -crf 18 -pix_fmt yuv420p \
  
  -c:a copy \
  
  output.mp4

  How can i modify the same command to apply the same operations on two secondary videos at the same time ?