Convert video files to animated GIF with FFmpeg

mov-to-gif.sh

# Usage: mov-to-gif path/to/input.mov [path/to/output.gif]
#
# This script generates high-quality GIFs at reasonable file sizes from practically *any* type of video file.
# By default, it reduces the framerate to 10 fps and scales the resolution to 800px wide (maintaining aspect ratio), but
# those parameters can be changed below.
#
# If no output path is specified (second argument), the script will use the input file's path with the extension changed
# to ".gif".
#
# EXISTING GIF FILES WILL BE OVERWRITTEN AUTOMATICALLY!
#
# FFmpeg can be installed via go/homebrew on Mac.
#
# Add this function to your ~/.bash_profile script and run `source ~/.bash_profile` in the terminal to use it.
function mov-to-gif() {
  local INPUT_PATH="$1"
  local OUTPUT_PATH="$2"
  if [ -z "$OUTPUT_PATH" ]; then
    local OUTPUT_PATH=$(echo "$INPUT_PATH" | sed -E 's/[.][[:alnum:]]+$/.gif/')
  fi

  local FPS='10'
  local WIDTH='800'

  # From http://blog.pkh.me/p/21-high-quality-gif-with-ffmpeg.html
  local PALETTE_PATH="/tmp/palette.png"
  local FILTERS="fps=$FPS,scale='min($WIDTH,iw)':-1:flags=lanczos"
  ffmpeg -y -v warning -i "$INPUT_PATH" -vf "$FILTERS,palettegen" "$PALETTE_PATH"
  ffmpeg -y -v warning -i "$INPUT_PATH" -i "$PALETTE_PATH" -lavfi "$FILTERS [x]; [x][1:v] paletteuse" "$OUTPUT_PATH"
}