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• Is there a way to prevent black frames from appearing at the start of a video when using -c:v copy ?

  11 juillet 2023, par MethanE

  My task seems simple. Using ffmpeg in terminal, I'm trying to pass through the exact video settings minus the audio, and i've been successful, except for the fact that the videos start with a frame of black before the actual video plays.

  


  currently using this :

  


  for i in *.*;do ffmpeg -i "$i" -an -c:v copy "${i%.*}_noaudio.mp4";done


  


  My current thought is it may be related to the error I'm getting (the vid still exports), but I'm not certain :
Missing key frame while searching for timestamp : 1001

  


  Input video metadata :

  


  Metadata :
major_brand : XAVC
minor_version : 16785407
compatible_brands : XAVCmp42iso2
creation_time : 2021-09-12T20:13:46.000000Z
Duration : 00:00:17.52, start : 0.000000, bitrate : 107315 kb/s
Stream #0:0(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 96798 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc (default)

  


  Googling led me to try not using -c:v copy as there might be a glitch related to h264 keyframes and instead using -c:v libx264 but i really don't want to have to re-encode as I don't want to lose any quality. The file I tried this on went from 135 mb down to 6.

  


  Thanks for your help. Kind of a newb at this.

  


• ffmpeg installation : pkg-config can't find package (using Homebrew)

  21 septembre 2018, par Rico Picone

  I’m trying to install ffmpeg with Homebrew using the command

  brew install ffmpeg --with-freetype

  but get

  ERROR: freetype2 not found using pkg-config

  If I check /usr/local/lib/pkgconfig, the file freetype2.pc exists. In fact,

  pkg-config --list-all

  includes freetype2.

  I’ve tried reinstalling pkg-config and freetype with Homebrew, reinstalling git, updating Homebrew, upgrading Homebrew, uninstalling and reinstalling all Homebrew packages, etc.

  brew doctor gives mostly a bunch of warnings about dylibs, config scripts, and header files, probably from recently moving to a new machine and copying files. I thought the config scripts might be related, but they’re all pyenv shims.

  I’m ok with a nuclear fix, but I feel like I’ve tried every nuclear option I know other than creating an entirely new user account.

• [FFMPEG]how to merger video clips into one output stream with timeline editing ?

  17 mars 2019, par Kent Wood

  I was trying to make a video editor, there are 2 short video clips, both duration are only 5 seconds. I placed a red background and set duration to 10s, then i placed video1 to 0-4s, placed video2 to 4-8
  command like this

  ffmpeg -i video1.mp4 -i video2.mp4 --complex_filter ^ 
  
  "color=c=red:s=640x480:duration=12[out],^
  
  [out][1]overlay=(W-w)/2:(H-h)/2:enable='between(t,4,8)'[out],^
  
  [out][0]overlay=(W-w)/2:(H-h)/2:enable='between(t,0,4)'[out]" output.mp4

  my thought is all video clips is as overlays on the red background, which exist all time, and be the first output,
  then, each video clip merges on as an overlay, then set and override ’out’ again.
  however, in fact, when the first video played over in the 5th second,(meanwhile,video2 has played 1 second already) the video just jammed, I think it is the problem about using the same tag as input and output.
  but how to merger them clips into one output stream with timeline editing ?