A simple screen recorder using ffmpeg, designed to be used headlessly, e.g., from a keyboard shortcut

recorder

#!/bin/bash

# ~/bin/recorder
#
# A simple screen recorder using ffmpeg, designed to be used headlessly, e.g.,
# from a keyboard shortcut. Calling the script again while another instance is
# running will kill the running instance, allowing you to toggle recording.
#
# REQUIRES: VAAPI, ffmpeg, notify-send, yad, beep 
#
# * Recordings are placed in ~/recordings, which will be created if it does not
#   exist.
# * A symlink to the latest recording is created at ~/recordings/latest.mp4
# * A PID file is created at ~/.recorder.pid
# * A PNG image is expected at ~/.recording.png, which will be used as a system
#   tray icon. Example: https://0e9b061f.github.io/files/recording.png
#
# A system tray icon is created during recording to alert the user when running
# headlessly. There will be no indication that recording is occuring if you
# don't have a system tray.
#
# A script like `vlc ~/recordings/latest.mp4` may be useful to view recordings
# immediately.

read -r -d '' USAGE <<'EOF'
A simple screen recorder designed for headless use

recorder [-f FPS] [-q CQP] [-t TIME]
  -f FPS
     Frames per second to record
     Default: 15
  -q CQP
     A number between 0-51. Controls recording quality. Higher numbers mean
     lower quality, and smaller files. Zero is lossless.
     Default: 26
  -t TIME
     End recording after TIME seconds
EOF

LIMIT=
FR="15"
CQP="26"
while getopts 'ht:f:q:' arg; do
  case "${arg}" in
    h) echo "${USAGE}"; exit 0 ;;
    t) LIMIT="${OPTARG}" ;;
    f) FR="${OPTARG}" ;;
    q) CQP="${OPTARG}" ;;
    *) exit 1 ;;
  esac
done
shift $((OPTIND - 1))
OUT="$(date +%s)"

PIDF="${HOME}/.recorder.pid"
ICON="${HOME}/.recording.png"
OUTD="${HOME}/recordings"
OUTF="${OUTD}/${OUT}.mp4"
LINK="${OUTD}/latest.mp4"

TIMER=
YAD=

function msg() {
  local msg
  msg="${1}"
  echo "${msg}"
  notify-send -t 4000 "RECORDER" "${msg}"
}

function err() {
  local msg
  msg="${1}"
  echo "ERROR: ${msg}"
  notify-send -u critical -t 8000 "RECORDER ERROR" "${msg}"
}

function smite() {
  kill "${1}" >& /dev/null
}

function on_exit() {
  [[ -n "${TIMER}" ]] && smite "${TIMER}"
  [[ -n "${YAD}" ]] && smite "${YAD}"
  rm -f "${PIDF}"
  ln -sf "${OUTF}" "${LINK}"
  beep -f 1000 -l 8 -D 0
}

mkdir -p "${OUTD}"

if [[ -f "${PIDF}" ]]; then
  PID="$(cat "${PIDF}")"
  if ps -p "${PID}" >& /dev/null; then
    if smite "${PID}"; then msg "Ended recording."
    else
      err "Unable to kill recorder"
      exit 1
    fi
  else
    if rm "${PIDF}"; then "${BASH_SOURCE[0]}" ${@}
    else
      err "Unable to remove stale PID file (${PIDF})"
      exit 1
    fi
  fi
else
  trap on_exit EXIT
  echo "Begin recording:"
  if [[ -f "${ICON}" ]]; then
    yad --notification --command='' --image="${ICON}" &
    YAD="${!}"
  fi
  beep -f 2000 -l 6 -D 0
  ffmpeg                              \
    -hwaccel vaapi                    \
    -hwaccel_output_format vaapi      \
    -f x11grab                        \
    -framerate "${FR}"                \
    -i "${DISPLAY}"                   \
    -c:v h264_vaapi                   \
    -compression_level 1              \
    -vaapi_device /dev/dri/renderD128 \
    -vf 'format=nv12,hwupload'        \
    -f mp4                            \
    -threads 12                       \
    -rc_mode 1                        \
    -qp ${CQP}                        \
    "${OUTF}"                         &
  FFPID="${!}"
  echo "${FFPID}" > "${PIDF}"
  if [[ -n "${LIMIT}" ]]; then
    (
      sleep "${LIMIT}"
      smite "${FFPID}" && msg "Ended recording."
    ) &
    TIMER="${!}"
  fi
  wait "${FFPID}"
fi