Record a screen (either full screen or grabbing a screen)

screen-record.sh

#!/bin/bash
# Copyright (C) 2016, 2017 Red Hat, Inc.
# Screen capture script (with fiddly goodies)
#
# Licensed under the GNU GPL, v2 or greater
#
# To record with sound, you must install an ffmpeg which is properly compiled
# with libalsa support.  This may require using RPMFusion repositories, and
# installing the libass libavcodec supported ffmpeg.

NAME=screencast-$(date +%Y%m%d%H%M)
FPS=4
THREADS=3
HEADLESS="no"
NO_SOUND="no"
DELAY=2

while [ $# -gt 0 ]; do
    if [ "$1" == "--headless" -o "$1" == "-n" ]; then
        HEADLESS="yes"
    fi

    if [ "$1" == "--name" -o "$1" == "-o" ]; then
        shift
        NAME="$1"
    fi

    if [ "$1" == "--no-sound" -o "$1" == "-s" ]; then
        NO_SOUND="yes"
    fi

    if [ "$1" == "--threads" -o "$1" == "-t" ]; then
        shift
        THREADS="$1"
    fi

    if [ "$1" == "--fps" -o "$1" == "-f" ]; then
        shift
        FPS="$1"
    fi

    if [ "$1" == "--delay" -o "$1" == "-d" ]; then
        shift
        DELAY="$1"
    fi

    shift
done

if [ "HEADLESS" != "yes" ]; then
    echo "Click the window to capture and get ready!"

    tmpfile=/tmp/screengrab.tmp.$$
    trap 'touch $tmpfile; rm -f $tmpfile' 0

    xwininfo > $tmpfile 2>/dev/null
    left=$(grep 'Absolute upper-left X:' $tmpfile | awk '{print $4}');
    top=$(grep 'Absolute upper-left Y:' $tmpfile | awk '{print $4}');
    width=$(grep 'Width:' $tmpfile | awk '{print $2}');
    height=$(grep 'Height:' $tmpfile | awk '{print $2}');
    geom="-geometry ${width}x${height}+${left}+${top}"
    echo "Geometry: ${geom}"
    size="-s ${width}x${height}"
    pos="+${left},${top}"
    echo "pos=$pos size=$size"
fi

sleep $DELAY

SOUND_OPTS="-f alsa -ac 2 -i pulse -acodec pcm_s16le $NAME-temp.wav"
SOUND_ARGS=""
if [ "$NO_SOUND" == "yes" ]; then
    SOUND_OPTS=""
    
fi

ffmpeg -y $SOUND_OPTS -f x11grab -r $FPS $size -i ${DISPLAY-0:0}${pos} -an -vcodec libx264 -preset ultrafast -threads 0 $NAME-temp.mp4

if [ "$NO_SOUND" == "yes" ]; then
    exit 0
fi

if [ "$1" != "--headless" ]; then
    echo "Merge audio+video and encode to webm - Abort now..." && read
fi
ffmpeg -i $NAME-temp.mp4 -i $NAME-temp.wav -acodec libvorbis -ab 128k -ac 2 -vcodec libvpx -qscale 8 -me_method full -mbd rd -flags +gmc+qpel+mv4 -trellis 1 -threads $THREADS $NAME.webm