example of making a side by side video with ffmpeg

side-by-side.sh

#!/bin/sh

# used to make this video:   https://youtu.be/jg9SOqIEYCk 
ffmpeg -i finalboss-crt.mkv -ss 00:00:00.600 -i finalboss-lcd.mp4 -filter_complex \
  "[0:v]crop=1287:1080:395:0[v1]; \
   [1:v]scale=480:360[v2]; \
   [v1][v2]xstack=inputs=2:layout=0_0|1287_40[v]; \
   [v]pad=1920:1080:0:0:color=black[v]; \
   [v]drawtext=text='CRT':fontcolor=white:fontsize=24:box=1:[email protected]:boxborderw=5:x=10:y=10, \
   drawtext=text='LCD':fontcolor=white:fontsize=24:box=1:[email protected]:boxborderw=5:x=1297:y=10[outv]" \
  -map "[outv]" -map 1:a -c:v libx264 -r 59.9402 -crf 23 -c:a aac -shortest output.mp4