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• Scale image with ffmpeg in bash script

  17 juin 2014, par Brian Bennett

  I’m playing with jclem’s Gifify bash script as a quick way to make GIFs for documentation. It runs on ffmpeg and ImageMagick and I’m trying to find a way to add a variable to scale the produced GIF so I don’t have to go back and add it again. I thought I added the d (resize) variable correctly, but the script fails and just prints the help contents. It does not show my added variable in that help readout. Any ideas ?

  Update

  I solved the problem with printing help contents rather than running the script, but now I’m receiving an error about the -scale parameter.

  convert: invalid argument for option `-scale': -vf @ error/convert.c/ConvertImageCommand/2513.

  Is this because of my if statement syntax for the scale parameter below ?

  #!/bin/bash
  
  
  
  function printHelpAndExit {
  
    echo 'Usage:'
  
    echo '  gifify -conx filename'
  
    echo ''
  
    echo 'Options: (all optional)'
  
    echo '  c CROP:   The x and y crops, from the top left of the image, i.e. 640:480'
  
    echo '  o OUTPUT: The basename of the file to be output (default "output")'
  
    echo '  n:        Do not upload the resulting image to CloudApp'
  
    echo '  r FPS:    Output at this (frame)rate (default 10)'
  
    echo '  s SPEED:  Output using this speed modifier (default 1)'
  
    echo '            NOTE: GIFs max out at 100fps depending on platform. For consistency,'
  
    echo '            ensure that FPSxSPEED is not > ~60!'
  
    echo '  x:        Remove the original file and resulting .gif once the script is complete'
  
    echo '  d SCALE:  Scales GIF image to specified dimensions (default no scale)'
  
    echo ''
  
    echo 'Example:'
  
    echo '  gifify -c 240:80 -o my-gif -x my-movie.mov'
  
    exit $1
  
  }
  
  
  
  noupload=0
  
  fps=10
  
  speed=1
  
  
  
  OPTERR=0
  
  
  
  while getopts "c:o:r:s:d:nx" opt; do
  
    case $opt in
  
      c) crop=$OPTARG;;
  
      h) printHelpAndExit 0;;
  
      o) output=$OPTARG;;
  
      n) noupload=1;;
  
      r) fps=$OPTARG;;
  
      s) speed=$OPTARG;;
  
      x) cleanup=1;;
  
      d) scale=$OPTARG;;
  
      *) printHelpAndExit 1;;
  
    esac
  
  done
  
  
  
  shift $(( OPTIND - 1 ))
  
  
  
  filename=$1
  
  
  
  if [ -z ${output} ]; then
  
    output=$filename
  
  fi
  
  
  
  if [ -z $filename ]; then printHelpAndExit 1; fi
  
  
  
  if [ $crop ]; then
  
    crop="-vf crop=${crop}:0:0"
  
  else
  
    crop=
  
  fi
  
  
  
  if [ $scale ]; then
  
    scale="-vf scale=${scale}:0:0"
  
  else
  
    scale=
  
  fi
  
  
  
  # -delay uses time per tick (a tick defaults to 1/100 of a second)
  
  # so 60fps == -delay 1.666666 which is rounded to 2 because convert
  
  # apparently stores this as an integer. To animate faster than 60fps,
  
  # you must drop frames, meaning you must specify a lower -r. This is
  
  # due to the GIF format as well as GIF renderers that cap frame delays
  
  # < 3 to 3 or sometimes 10. Source:
  
  # http://humpy77.deviantart.com/journal/Frame-Delay-Times-for-Animated-GIFs-214150546
  
  echo 'Exporting movie...'
  
  delay=$(bc -l <<< "100/$fps/$speed")
  
  temp=$(mktemp /tmp/tempfile.XXXXXXXXX)
  
  
  
  ffmpeg -loglevel panic -i $filename $crop -r $fps -f image2pipe -vcodec ppm - >> $temp
  
  
  
  echo 'Making gif...'
  
  cat $temp | convert +dither -layers Optimize -delay $delay -scale $scale - ${output}.gif
  
  
  
  if [ $noupload -ne 1 ]; then
  
    open -a Cloud ${output}.gif
  
  
  
    echo `pbpaste`
  
  
  
    if [ $cleanup ]; then
  
      rm $filename
  
      rm ${output}.gif
  
    fi
  
  else
  
    echo ${output}.gif
  
  fi

• How to use ffmpeg to add jpeg image before and after the video [migrated]

  26 janvier 2016, par Chito Cheng

  I am using the latest version 2.8.5 ffmpeg on Windows and I want to add 5s intro jpeg frame at the beginning of the video starts, and a 5s jpeg end frame at the end of the video.

  I found a lot of example online, but seems all of them are using previous version of ffmpeg, and none of them works with the latest version.

  Can anyone tell me how I can do that with the latest version.

• Inserting an image inside a video every few frames using ffmpeg

  9 mars 2017, par Erez Hochman

  Can I use FFMPEG to insert an image every 20 frames in a video ?
  I’m trying to create a subliminal message experiment and I thought it would be an easy way to make it but I can’t find anything online.

  I tried to make something myself and created a script that :
  1.splits a file into audio and video files
  2.splits the video into frames
  3.overwrites every 20th image in the sequence with the message image
  4.re-encoding the video
  5.concatenating it with the original audio

  this works but it’s way more disk space consuming to be comfortable, is there a better way to do this ?
  any advice or thought would be happily welcome.