gif_from_cli_3.sh

#!/bin/sh
# https://trac.ffmpeg.org/wiki/Capture/Desktop

FILENAME=${1:-"screencast"}
FPS=${2:-"30"}
WIDTH=${3:-"1366"}

HEIGHT="768"
DIMENSIONS="${WIDTH}x${HEIGHT}"
MP4="$FILENAME.mp4"
PALETTE="/tmp/palette.png"
FILTERS="fps=$FPS,scale=$WIDTH:-1:flags=lanczos"

printf "\n\033[0;35mRecording to $MP4, $FPS fps, $DIMENSIONS...\033[0m\n\n"

ffmpeg -v error -framerate $FPS -video_size $DIMENSIONS -f x11grab -i :0.0+0,0 -vcodec libx264 -crf 0 -preset ultrafast -acodec pcm_s16le $MP4

printf "\n\033[0;35m$MP4 saved, converting to gif [$FPS fps, $DIMENSIONS > $FILENAME.gif]...\033[0m\n\n"

# http://blog.pkh.me/p/21-high-quality-gif-with-ffmpeg.html

ffmpeg -v warning -i $MP4 -vf "$FILTERS,palettegen" -y $PALETTE
ffmpeg -v warning -i $MP4 -i $PALETTE -lavfi "$FILTERS [x]; [x][1:v] paletteuse" -y $FILENAME.gif