x11grab script: Screen record your desktop and audio sources with `ffmpeg` FOR FREE!

x11grab.sh

#!/bin/bash

# Usage:
#
#    AVOUTFILE=screecap.mkv x11grab
#
# Records the screen, the output to the speakers and whatever your default mic recording device is.
# After starting the record, you can toggle which input is recorded with the GUI interface: `pavucontrol`
# or direct this with $PULSE_MIC_SOURCE
# Use `pactl list sources` to list the available sources.


if [ -n "$DEBUG" ]; then
  set -x
fi
FFMPEG=${FFMPEG:-"ffmpeg -hide_banner"}

#####! BEGIN: Configuration Section !#####

# 0-index of which screen to capture on the $DISPLAY
SCREEN=${1:-0}

# The "$W,$H" factor for the offset. What's the offset of the X,Y anchor for the top-left to start recording?
OFFSET=${OFFSET:-${2:-0,0}}

# This was more relevant on a computer with 2 monitors. If you have >1 display, you can include them in this list.
SCREENS=(
'0,0'
)

# If the sizes of the displays are different, you can indicate them here.
SIZES=(
1920x1080
1920x1080
)

# Monitor the output sent to the speakers by using Pulse audio monitor.
PULSE_AUDIO_SOURCE=${PULSE_AUDIO_SOURCE:-alsa_output.pci-0000_00_1f.3.analog-stereo.monitor}
PULSE_MIC_SOURCE=${PULSE_MIC_SOURCE:-default}

# Set the video and audio codecs to be used in the output.
ACODEC=${ACODEC:-aac}
VCODEC=${VCODEC:-h264}

# Output file.
AVOUTFILE=${AVOUTFILE:-/tmp/x11grab.mp4}

# Size of the screen.
SIZE=${SIZE:-${SIZES[$SCREEN]:-$3}}
# Offset is how many pixels from the top-left corner of the screen to offset before capturing the screen.
# NOTE: ffmpeg will complain if you indicate a size that is larger than the screen size.
OFFSET=${OFFSET:-$SIZES[0]}

# This loop allows for basic processing of some command line options in case you don't know the env var names. (read:accessibility)
while getopts 'osavf' opt; do
  case "$opt" in
    o) OFFSET=$OPTARG ;;
    s) SIZE=$OPTARG ;;
    a) ACODEC=$OPTARG ;;
    v) VCODEC=$OPTARG ;;
    f) AVOUTFILE=$OPTARG ;;
  esac
done

#####! END: Configuration Section !#####

# Audio Input options.
AIOPTS=${AIOPTS:-"-thread_queue_size 256 -f pulse -i $PULSE_AUDIO_SOURCE -thread_queue_size 256 -f pulse -i $PULSE_MIC_SOURCE"}
# Video Input options.
VIOPTS=${VIOPTS:-"-thread_queue_size 64 -analyzeduration 100M -probesize 100M -framerate ${FRAME_RATE:-30} -f x11grab -s ${SIZE} -i $DISPLAY+${OFFSET}"}
# Audio Output options.
AOOPTS=${AOOPTS:-"-c:a ${ACODEC} -filter_complex '[0:a][1:a]amix[audio]' -map [audio] -map 2:v"}
# Video Output options.
VOOPTS=${VOOPTS:-"-c:v ${VCODEC} -preset veryfast -crf ${CRF:-28} -r ${FRAME_RATE:-30} -pix_fmt yuv420p"}

AVOPTS="$AIOPTS $VIOPTS $AOOPTS $VOOPTS -y $AVOUTFILE"

pkill compton
#trap "$HOME/bin/compton.sh" EXIT

echo "Execute: $FFMPEG $AVOPTS"
eval "$FFMPEG $AVOPTS"

# These are here for reference to give an idea of how these commands evolved.
#ffmpeg -f pulse -i default -f x11grab -s 1920x1080 -i :0.0+0,92 -q:v 1 -y /tmp/live.mkv -acodec ac3 -ar 48000 -b 224k -vcodec libx264 -bt 8192k -r 50

# avconv is an alternative to ffmpeg. Doesn't quite behave the same, but very similar options.
#avconv -f pulse -i default -f x11grab -s 1920x1080 -i :0.0+0,92 -y -f matroska -b:a 224k -b:v 8192k -c:a ac3 -c:v libx264 -y /tmp/live.mkv