Grab a frame of a video file (Specifically for Mac)

Get Frame.md

Installing the script

sudo mkdir -p /usr/local/bin &>/dev/null ; sudo curl -fsSL -o /usr/local/bin/getframe "https://gist.githubusercontent.com/snown/a818afd18c9e2087731bdf7ce0a85195/raw/getframe.sh" && sudo chmod a+x /usr/local/bin/getframe

Install the folder action

getframe install-folder-action

getframe.sh

#!/usr/bin/env bash

################################################################################
# Config
################################################################################
SEEK_TIME="00:00:03.000"
VIDEO_FILE_TYPES=(
  mkv
  webm
  flv
  vob
  ogg
  ogv
  drc
  gifv
  mng
  avi
  mov
  qt
  wmv
  yuv
  rm
  rmvb
  asf
  amv
  mp4
  m4v
  mp
  svi
  3gp
  flv
  f4v
)

################################################################################
# Main Functions
################################################################################

function getframe::print_help {
  local script_name="$(basename "$0")"
  _pansi --reset
  here_printf <<-HELP
$(_pansi --bold "USAGE:")
  ${script_name} [-h|--help]
  ${script_name} [-v|--verbose]... [-q|--quiet] [-f|--force] [-s|--seek <seek_time>] [-i|--input <video_file>]... <video_file> [<video_file>]...
  ${script_name} install-folder-action
  
$(_pansi --bold "FLAGS:")
  -h, --help  Print this help message.
  
$(_pansi --bold "OPTIONS:")
  -v, --verbose How verbose logging should be. Can be passed multiple times.
  -q, --quiet   Suppress extraneous printing to the terminal. 
                Cancels any previous '-v' flags.
  -f, --force   Force overwrite existing frame grabs. Skips files if not
                specified.
  -s, --seek    Set how far into the video the frame should be grabbed from.
                Seek time can be specified in one of two ways:
                  '$(_pansi --italic --underline "[HH:]MM:SS[.m...]")' Where '$(_pansi --italic HH)' is an optional number of hours,
                  '$(_pansi --italic MM)' is the number of minutes, '$(_pansi --italic SS)' is number of seconds, 
                  and '$(_pansi --italic m)' is a decimal value of '$(_pansi --italic SS)'
                  '$(_pansi --italic --underline "S+[.m...]")' Where '(_pansi --italic S)' expresses the number of seconds, with 
                  the optional decimal part '(_pansi --italic m)'.
  -i, --input   A video file from which to grab a frame. 
                Can be repeated any number of times
  <video_file>  A video file from which to grab a frame. 
                Can be repeated any number of times. 
                At least one has to be specified, unless using '-i|--input'
                
$(_pansi --bold "COMMANDS:")
  install-folder-action Installs a folder action on the system to be used with Finder. Will call this script anytime a file is added to the specified folder.
HELP
}

VERBOSITY=1
function getframe {
  local passthrough_args=()
  
  if [[ $# -eq 0 ]]; then
    getframe::print_help
    exit 1
  fi
  
  while [[ $# -gt 0 ]]; do
    local _key="$1"
    case "${_key}" in
    --install-watch-script|install-folder-action|install)
      getframe::install_watch_script
      exit 0
      ;;
    -v|--verbose)
      VERBOSITY=$((VERBOSITY + 1))
      ;;
    -q|--quiet)
      VERBOSITY=0
      ;;
    -h|--help)
      getframe::print_help
      exit 0
      ;;
    -v?*|-q?*|-h?*|-f?*)
      local _next="${_key:2}"
      local _current="${_key:0:2}"
      if [[ -n "${_next}" && "${_next}" != "${_key}" ]]; then
        _begins_with_short_option -o "vqhf" "${_next}" && shift && set -- "${_current}" "-${_next}" "$@"
        getframe::log -v 5 "Next arguments: $@"
        continue
      fi
      ;;
    *)
      getframe::log -v 5 "Passthrough Key: ${_key}"
      passthrough_args+=( "${_key}" )
      ;;
    esac
    shift
  done
  
  # Perform image extraction
  getframe::make_image "${passthrough_args[@]}"
}


################################################################################
# Helper Functions
################################################################################

function _pansi {
  if ! command -v pansi &>/dev/null; then
    local tmp_pansi="$(mktemp -t pansi)"
    curl -fsSL -o "${tmp_pansi}" "https://raw.githubusercontent.com/snown/pansi/master/pansi"
    source "${tmp_pansi}"
  fi
  
  pansi "$@"
}

function _ffmpeg {
  # Check for ffmpeg
  if ! command -v ffmpeg &>/dev/null; then
    
    # if no ffmpeg look for homebrew
    if ! command -v brew &>/dev/null; then
      
    	# if no homebrew, install homebrew
      getframe::log -v 1 "Installing Homebrew..."
    	ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
    fi
    
    # Install ffmpeg
    getframe::log -v 1 "Installing FFMpeg..."
    brew install ffmpeg
  fi
  
  ffmpeg "$@"
}

# Find the absolute path of an exiting file or directory
#-------------------------------------------------------------------------------
function _abspath {
    if [[ -d "$1" ]]
    then
        pushd "$1" >/dev/null
        pwd
        popd >/dev/null
    elif [[ -e $1 ]]
    then
        pushd "$(dirname "$1")" >/dev/null
        echo "$(pwd)/$(basename "$1")"
        popd >/dev/null
    else
        echo "$1" does not exist! >&2
        return 127
    fi
}

function _scriptSudo {
  local SUDO_IS_ACTIVE
  SUDO_IS_ACTIVE=$(sudo -n uptime 2>&1|grep "load"|wc -l)
  if [[ ${SUDO_IS_ACTIVE} -le 0 ]]; then
    # Ask for the administrator password upfront
    sudo -v

    # Keep-alive: update existing `sudo` time stamp until `.osx` has finished
    while true; do sudo -n true; sleep 60; kill -0 "$$" || exit; done 2>/dev/null &
  fi
  
  sudo "$@"
}

function _begins_with_short_option {
	local next_option
  local all_short_options=""
  
  while [[ $# -gt 0 ]]; do
    local _key="$1"
    case "${_key}" in
    -o|--options)
      all_short_options="${all_short_options}$2"
      shift
      ;;
    *)
      if [[ $# -gt 1 ]]; then
        shift && set -- "-o" "${_key}" "$@"
        continue
      fi
      next_option="${1:0:1}"
      ;;
    esac
    shift
  done
  
	test "${all_short_options}" = "${all_short_options/${next_option}/}" && return 1 || return 0
}

function getframe::log {
  local print_level=0
  
  if [[ "$1" == "-v" ]]; then
    print_level=$2
    shift
    shift
  fi
  
  if [[ $print_level -le $VERBOSITY ]]; then
    for string in "$@"; do
      echo "${string}" > /dev/tty
    done
  fi
}

function getframe::is_video_file {
  local result=false
  local nocasematch_bu=$(shopt -p nocasematch; true)
  
  shopt -s nocasematch
  for file_ext in "${VIDEO_FILE_TYPES[@]}"; do
    if [[ "$1" == *"${file_ext}" ]]; then
      result=true
      break
    fi
  done
  
  # Restore case matching
  ${nocasematch_bu}
  
  ${result}
}

function getframe::install_watch_script {
  local username="$(whoami)"
  local script_path="$(_abspath "$0")"
  local tmp_script="$(mktemp -t getframe_watch_script)"
  local installation_path="/Library/Scripts/Folder Action Scripts/add - Still Frame from Videos.scpt"
  
  
  cat > "${tmp_script}" <<-APPLESCRIPT
on adding folder items to theAttachedFolder after receiving theNewItems
	set posixDirectory to the quoted form of (POSIX path of (theAttachedFolder as alias))
	try
		do shell script "sudo -u '${username}' -i getframe " & posixDirectory
	on error
    try
      do shell script "'${script_path}' " & posixDirectory
    on error
  		tell application "Finder"
  			display alert "Error" message "Could not find 'getframe' command"
  		end tell
  	end try
	end try
end adding folder items to
APPLESCRIPT
  
  _scriptSudo mkdir -p "$(dirname "${installation_path}")"
  if [[ -e "${installation_path}" ]]; then
    _scriptSudo rm "${installation_path}"
  fi
  _scriptSudo mv "${tmp_script}" "${installation_path}"
}

function getframe::make_image {
  local input_candidates=()
  local seeking="${SEEK_TIME}"
  local force=false
  
  # Parse arguments
  while [[ $# -gt 0 ]]; do
    local _key="$1"
    case "${_key}" in
    -i|--input)
      local input="$2"
      shift
      
      local input_candidates=()
      if [[ ! -r "${input}" ]]; then
        getframe::log -v 2 "Cannot read input: ${input}"
        shift
        continue
      fi
      
      if [[ -d "${input}" ]]; then
        while IFS= read -d '' -r file; do input_candidates+=("$file"); done < <(find "${input}" -maxdepth 1 -type f -not -iname "*.png" -print0)
      elif [[ -f "${input}" ]]; then
        input_candidates=( "${input}" )
      else
        getframe::log -v 2 "Input needs to be a file or directory: ${input}"
        shift
        continue
      fi
      ;;
    -s|-ss|--seek)
      seeking="$2"
      shift
      ;;
    -f|--force)
      getframe::log -v 5 "Should force"
      force=true
      ;;
    *)
      getframe::log -v 5 "Possible positional input: \"${_key}\""
      if [[ -f "${_key}" || -d "${_key}" ]]; then
        getframe::log -v 5 "\"${_key}\" is either a file or directory"
        shift && set -- "--input" "${_key}" "$@"
        getframe::log -v 5 "Input params: $*"
        continue
      else
        getframe::log -v 1 "Unrecognized option: ${_key}"
        getframe::print_help
        exit 1
      fi
      ;;
    esac
    shift
  done
  
  local video_files=()
  for file in "${input_candidates[@]}"; do
    if ! getframe::is_video_file "${file}"; then
      getframe::log -v 3 "Input was not recognized as a video file: ${file}"
      continue
    fi
    
    if [[ -e "${file%.*}.png" && "${force}" != true ]]; then
      getframe::log -v 3 "Frame grab already exists for file: ${file}"
      continue
    fi
    
    video_files+=( "${file}" )
  done
  
  for file in "${video_files[@]}"; do
    _ffmpeg -y -ss "${seeking}" -i "${file}" -frames:v 1 "${file%.*}.png"
  done
}

################################################################################
# Run
################################################################################

getframe "$@"