Concat 2 video and add watermark first video ffmpeg
Concatenate can be found from this link
In case of using same codec
!echo &quot;file 'video_1.mp4'&quot; &gt; list.txt
!echo &quot;file 'video_2.mp4'&quot; &gt;&gt; list.txt

Add watermark at (x=1, y=1) coordinated
!ffmpeg -y -f concat -safe 0 -i list.txt -i watermark.png -filter_complex &quot;overlay=1:1&quot; output.mp4

I don't quite understand your description, but i think it fits your title.