Adding GIF2WebM, but it actually works will with any video input file.

plugins/available/gif.plugin.bash

@@ -1,7 +1,10 @@
 cite about-plugin
-about-plugin 'video to gif helper functions'
+about-plugin 'video to gif, gif to WebM helper functions'
 
-# From https://gist.github.com/SlexAxton/4989674#comment-1199058
+# Based loosely on:
+#  https://gist.github.com/SlexAxton/4989674#comment-1199058
+#  https://linustechtips.com/main/topic/343253-tutorial-convert-videogifs-to-webm/
+#  and other sources
 # Renamed gifify to v2gif to go avoid clobbering https://github.com/jclem/gifify
 # Requirements (Mac OS X using Homebrew): brew install ffmpeg giflossy imagemagick
 # Requirements on Ubuntu: sudo apt install ffmpeg imagemagick ; plus install https://github.com/pornel/giflossy
@@ -159,3 +162,108 @@ function v2gif {
 
   echo "$(tput setaf 2)Done.$(tput sgr 0)"
 }
+
+function any2webm() {
+  about 'Converts an movies and Animated GIF files into an into a modern quality WebM video.'
+  group 'gif'
+  param '1: GIF/video file name(s)'
+  param '2: -s <WxH> ; Optional: set <W>idth and <H>eight in pixels'
+  param '3: -d       ; Optional: delete the original file if succeeded'
+  param '4: -t       ; Optional: Tag the result with quality stamp for comparison use'
+  param '5: -f <num> ; Optional: Change number of frames per second'
+  param '6: -b <num> ; Optional: Set Bandwidth (quality/size of resulting file), Defaults to 2M (bits/sec, accepts fractions)"'
+  param '7: -a <num> ; Optional: Alert if resulting file is over <num> kilobytes (default is 5000, 0 turns off)'
+  example '$ any2webm foo.gif'
+  example '$ any2webm *.mov -b 1.5M -s 600x480'
+
+  # Parse the options
+  local args=$(getopt -l alert -l "bandwidth:" -l "width:" -l del,delete -l tag -l "fps:" -l webm -o "a:b:w:f:dt" -- "$@")
+
+  local del_after=""
+  local size=""
+  local webmtagopt=""
+  local webmtag=""
+  local defaultfps=10
+  local fps=""
+  local bandwidth="2M"
+  local alert=5000
+  eval set -- "$args"
+  while [ $# -ge 1 ]; do
+    case "$1" in
+      --)
+        # No more options left.
+        shift
+        break
+        ;;
+      -d|--del|--delete)
+        # Delete after
+        del_after="true"
+        shift
+        ;;
+      -s|--size)
+        size="-s $2"
+        webmtag="${webmtag}-s$2"
+        shift 2
+        ;;
+      -t|--tag)
+        # mark with a quality tag
+        webmtagopt="true"
+        shift
+        ;;
+      -f|--fps)
+        # select fps
+        fps="-r $2"
+        webmtag="${webmtag}-f$2"
+        shift 2
+        ;;
+      -b|--bandwidth)
+        # select bandwidth
+        bandwidth="$2"
+        webmtag="${webmtag}-b$2"
+        shift 2
+        ;;
+      -a|--alert)
+        # set size alert
+        alert="$2"
+        shift 2
+        ;;
+    esac
+  done
+
+  # Done Parsing, all that's left are the filenames
+  local movies="$*"
+
+  if [[ -z "$movies" ]]; then
+    echo "$(tput setaf 1)No input files given. Example: any2webm file [file...] [-w <max width (pixels)>] < $(tput sgr 0)"
+    return 1
+  fi
+
+  # Prepare the quality tag if requested.
+  [[ -z "$webmtag" ]] && webmtag="-default"
+  [[ -z "$webmtagopt" ]] && webmtag=""
+
+  for file in $movies ; do
+
+    local output_file="${file%.*}${webmtag}.webm"
+
+    echo "$(tput setaf 2)Creating '$output_file' ...$(tput sgr 0)"
+
+    ffmpeg -loglevel panic -i "$file" \
+      -c:v libvpx -crf 4 -threads 0 -an -b:v $bandwidth -auto-alt-ref 0 \
+      -quality best $fps $size -pix_fmt yuva420p "$output_file" || return 2
+
+    # Checking if the file is bigger than Twitter likes and warn
+    if [[ $alert -gt 0 ]] ; then
+      local out_size=$(wc --bytes < "$output_file")
+      if [[ $out_size -gt $(( alert * 1000 )) ]] ; then
+        echo "$(tput setaf 3)Warning: '$output_file' is $((out_size/1000))kb, keeping '$file' even if --del requested.$(tput sgr 0)"
+        del_after=""
+      fi
+    fi
+
+    [[ "$del_after" = "true" ]] && rm "$file"
+
+  done
+
+  echo "$(tput setaf 2)Done.$(tput sgr 0)"
+}