recordscreen: A bash script for timelapse recordinging two separate X displays, and creating a picture-in-picture overlay with one display

recordscreen.sh

#!/bin/bash

if [ ! $# -eq 2 ] ; then
    echo "Usage: ./recordscreen delay outputfolder"
    exit
fi

if [ ! -d $outputFolder ] ; then
    echo "Output folder does not exist"
    exit
fi

# $1:output
function captureScreenDump {
    xwd -root -out $1
}

# $1:input-file $2:output-file
function prepareThumbnail {
    convert $1 -thumbnail 300x300 -bordercolor "#881111aa" -border 2 \
        \( +clone -background black -shadow 100x3+2+2 \) \
        +swap -background none -layers merge +repage $2
}

# $1:left-image  $2:right-image  $3:output-frame
function prepareFinalFrame {
    pictureInPictureOffset=+1588+837
    convert -composite $1 $2 -geometry $pictureInPictureOffset $3
}

# $1:counter  $2:folderOuput
function doFrameCapture {
    # Filenames for left and right screen
    outfile=`printf '%.5d' $1`-`date +"%Y-%m-%d-%s"`
    left=${2}/left/${outfile}
    right=${2}/right/${outfile}

    # Capture both screens at the same time
    (DISPLAY=:0.0 captureScreenDump ${left}.xwd && pid1=$!) &
    (DISPLAY=:0.1 captureScreenDump ${right}.xwd && pid2=$!)
    wait $pid1 $pid2

    # Prepare right screen as thumbnail
    thumbnail=${right}-thumbnail
    prepareThumbnail ${right}.xwd ${thumbnail}.png

    # Create final frame from left frame and thumbnail of right frame
    outfileFinal=${2}/frames/`printf '%.5d' $1`
    prepareFinalFrame ${left}.xwd ${thumbnail}.png ${outfileFinal}.png

    # Cleanup:
    rm $left.xwd $right.xwd $thumbnail.png
}


###################  PROGRAM CODE STARTS  ###################
delay=$1
outputFolder=$2
mkdir $outputFolder/{left,right,frames}
curr=0
while sleep $delay;
do
    ((curr++))
    (doFrameCapture $curr $outputFolder &)
done
####################  -----------------  ####################

recordscreenalt.sh

#!/bin/bash

# Setup:
####################
# Automatic setup detection using xrandr
xrandrOutput=`xrandr --query`
leftGeometry=`echo "$xrandrOutput" | grep -P "\sconnected" \
                | grep -oP '\d+x\d+\+0\+\d+'`
rightGeometry=`echo "$xrandrOutput" | grep -P "\sconnected" \
                | grep -oP '\d+x\d+\+\d{2,}\+\d+'`
primaryGeomtry=`echo "$xrandrOutput" | grep -P "\sconnected primary" \
                | grep -oP '\d+x\d+\+\d+\+\d+'`
if [[ "$primaryGeomtry" == "$leftGeometry" ]] ; then
    mainMonitor=left
elif [[ "$primaryGeomtry" == "$rightGeometry" ]] ; then
    mainMonitor=right
else
    echo "Failed to detect main monitor"
fi
leftMonitor=${leftGeometry%%+*}
rightMonitor=${rightGeometry%%+*}
pipSize=340x340
pipOffset=+30+20

# Implicit variables
leftMonitorWidth=${leftMonitor%x*}

echo "leftMonitor:  " $leftMonitor
echo "rightMonitor: " $rightMonitor
echo "pipSize:      " $pipSize
echo "pipOffset:    " $pipOffset
echo "mainMonitor:  " $mainMonitor

########################
if  [[ ! "$mainMonitor" == "left" ]] && \
    [[ ! "$mainMonitor" == "right" ]] ; then
    echo "Bad mainMonitor variable"
    exit
fi

if [ ! $# -eq 2 ] ; then
    echo "Usage: ./recordscreen delay outputfolder"
    exit
fi

if [ ! -d $outputFolder ] ; then
    echo "Output folder does not exist"
    exit
fi

gsettings set org.gnome.desktop.sound event-sounds false

# $1:output
function captureScreenDump {
    xwd -root -out $1
}

# $1:input-file $2:output-file
function prepareThumbnail {
    if [[ "$mainMonitor" == "left" ]] ; then
        geometry=${rightMonitor}+${leftMonitorWidth}+0
    else
        geometry=${leftMonitor}+0+0
    fi
    convert $1 -crop $geometry -thumbnail $pipSize \
        -bordercolor "#881111aa" -border 2 \
        \( +clone -background black -shadow 100x3+2+2 \) \
        +swap -background none -layers merge +repage $2
}

# $1:captured-image  $2:pip-thumbnail  $3:output-frame
function prepareFinalFrame {
    geometry=
    if [[ "$mainMonitor" == "left" ]] ; then
        geometry=${leftMonitor}+0+0
    else
        geometry=${rightMonitor}+${leftMonitorWidth}+0
    fi
    convert -crop $geometry ${1} ${1}.tmp.xwd
    convert -composite ${1}.tmp.xwd $2 -gravity SouthEast \
        -geometry $pipOffset $3
    rm ${1}.tmp.xwd
}

# $1:counter  $2:folderOuput
function doFrameCapture {
    # Filenames for capture and right screen
    outfile=`printf '%.5d' $1`-`date +"%Y-%m-%d-%s"`
    capture=${2}/capture/${outfile}
    pip=${2}/pip/${outfile}

    # Capture both screens at the same time
    captureScreenDump $capture.xwd
    prepareThumbnail $capture.xwd $pip.png

    # Create final frame from left frame and thumbnail of right frame
    outfileFinal=${2}/frames/`printf '%.5d' $1`
    prepareFinalFrame ${capture}.xwd ${pip}.png ${outfileFinal}.png

    # Cleanup:
   rm -f $capture.xwd $pip.png
}

function finalize() {
    rm -f $outputFolder/{capture,pip}/*
    rmdir $outputFolder/{capture,pip}
    gsettings set org.gnome.desktop.sound event-sounds true
    exit
}
trap finalize SIGINT SIGTERM

###################  PROGRAM CODE STARTS  ###################
delay=$1
outputFolder=$2
curr=0
if [ -e $outputFolder/frames ] ; then
    lastFrame=`ls -1 $outputFolder/frames/ | tail -n 1`
    curr=`echo ${lastFrame%.*} | sed 's/^0*//'`
    while true; do
        read -p "Recording in progress (currently $curr frames)
Do you wish to continue at frame "$((curr+1))"? [y/n] " yn
        case $yn in
            [Yy]* ) break;;
            [Nn]* ) exit;;
            * ) echo "Please answer yes or no.";;
        esac
    done
fi

if [ ! -e $outputFolder/capture ] ; then mkdir $outputFolder/capture ; fi
if [ ! -e $outputFolder/pip ]     ; then mkdir $outputFolder/pip ;     fi
if [ ! -e $outputFolder/frames ]  ; then mkdir $outputFolder/frames ;  fi

while sleep $delay;
do
    ((curr++))
    (doFrameCapture $curr $outputFolder &)
done
####################  -----------------  ####################

why don't you just ffmpeg -s 1280x720 -f x11grab -i :0.0+100,100 -filter:v "setpts=PTS/30" -r 30 though?

@phiresky
Does that capture multiple screens?

There's a great script called ffcast that automates selecting an area and recording it, with x11grab as you mentioned. I summarised how to use it and convert the results to GIF here. (I don't know if my method works with multiple screens though...)

Why using xwd -root -out foo.xwd instead of import -window root foobar.png? import is from ImageMagick, the same package that provides convert.