Tvheadend

Yes possible with option "MPEG-TS Spawn" in streaming profile.

can you please give me an example of the command?

this streaming profile is present only in the unstable version?

Need reading ;)
https://www.torchlightmedia.co.uk/add-watermark-or-logo-to-videos-with-ffmpeg-filters-tutorial/

yes i was able to add from line command and ffmpeg the logo!

but do i have to add that command in tvheadend in streaming profile?

So add command to TVH interface and go to next case.
Use search in forum there are similar questions.

new rpi wrote:

this streaming profile is present only in the unstable version?

where i can add the command in tvh interface i am using tvh 4.2

TRYED:
ffmpeg -y -i pipe:0 -i ./home/ubuntu/ffmpeg_sources/ffmpeg/test.png -filter_complex "overlay=10:10" -preset superfast -bitrate 2000k -bufsize 1500k -c:v libx264 -c:a aac -c:s copy -f mpegts pipe:1

while this is the comand working that add on a mp4 file my logo
ffmpeg -y -i mylink -i ./test.png -filter_complex "overlay=10:10" OUT.mp4

i can see video but no logo