with subprocess.Popen's start_new_session set to True (output via ps -efjxa):
PPID PID PGID SID TTY TPGID STAT UID TIME COMMAND
1 561 561 561 ? -1 Ss 0 0:00 /usr/sbin/sshd -D
561 7432 7432 7432 ? -1 Ss 0 0:00 \_ sshd: pi [priv]
7432 7450 7432 7432 ? -1 S 1000 0:02 | \_ sshd: pi@pts/0
7450 7451 7451 7451 pts/0 12152 Ss 1000 0:06 | \_ -zsh LC_TERMINAL_VERSION=3.4.8 LANG=en_GB.UTF-8 LC_TERMINAL=iTerm2 USER=pi LOGNAME=pi HOME=/home/pi PATH=/usr/local/bin:/usr/bin:/bin:/
7451 12152 12152 7451 pts/0 12152 S+ 1000 0:02 | \_ python3 ./broadcast --url https://www.youtube.com/watch?v=53yEyj0mjfo LC_TERMINAL_VERSION=3.4.8 LANG=en_GB.UTF-8 LC_TERMINAL=iTerm2
12152 12177 12177 12177 ? -1 Ss 1000 0:00 | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v=53yEyj0mjfo
12177 12178 12177 12177 ? -1 RLl 1000 0:02 | \_ ffmpeg -i /dev/fd/63 -i /dev/fd/62 -c:v copy -c:a mp2 -b:a 192k -f mpegts - SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabaga
12178 12180 12177 12177 ? -1 S 1000 0:00 | | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v=53y
12180 12184 12177 12177 ? -1 S 1000 0:04 | | | \_ /usr/bin/python3 /usr/local/bin/yt-dlp --extractor-args youtube:player_client=android https://www.youtube.com/watch
12180 12186 12177 12177 ? -1 Sl 1000 0:00 | | | \_ mbuffer -q -Q -m 52428800b SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R PWD=/home/pi/piwall2 LOGNAME=
12178 12182 12177 12177 ? -1 S 1000 0:00 | | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v=53y
12182 12190 12177 12177 ? -1 S 1000 0:03 | | \_ /usr/bin/python3 /usr/local/bin/yt-dlp --extractor-args youtube:player_client=android https://www.youtube.com/watch
12182 12191 12177 12177 ? -1 Sl 1000 0:00 | | \_ mbuffer -q -Q -m 5242880b SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R PWD=/home/pi/piwall2 LOGNAME=p
12177 12179 12177 12177 ? -1 S 1000 0:00 | \_ tee /dev/fd/63 /dev/fd/62 SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R PWD=/home/pi/piwall2 LOGNAME=pi XDG_SE
12179 12181 12177 12177 ? -1 S 1000 0:00 | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v=53y
12181 12185 12177 12177 ? -1 Sl 1000 0:00 | | \_ mbuffer -q -l /tmp/mbuffer.out -m 209715200b SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R PWD=/home/p
12181 12187 12177 12177 ? -1 S 1000 0:00 | | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v
12187 12189 12177 12177 ? -1 SL 1000 0:00 | | \_ ffmpeg -re -i pipe:0 -c:v copy -c:a copy -f mpegts - SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R
12179 12183 12177 12177 ? -1 S 1000 0:00 | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v=53y
12183 12188 12177 12177 ? -1 R 1000 0:01 | \_ python3 /home/pi/piwall2/msend_video --log-uuid TFLJL SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R PW
with subprocess.Popen's start_new_session set to False (output via ps -efjxa):
PPID PID PGID SID TTY TPGID STAT UID TIME COMMAND
1 561 561 561 ? -1 Ss 0 0:00 /usr/sbin/sshd -D
561 7432 7432 7432 ? -1 Ss 0 0:00 \_ sshd: pi [priv]
7432 7450 7432 7432 ? -1 S 1000 0:03 | \_ sshd: pi@pts/0
7450 7451 7451 7451 pts/0 12349 Ss 1000 0:07 | \_ -zsh LC_TERMINAL_VERSION=3.4.8 LANG=en_GB.UTF-8 LC_TERMINAL=iTerm2 USER=pi LOGNAME=pi HOME=/home/pi PATH=/usr/local/bin:/usr/bin:/bin:/
7451 12349 12349 7451 pts/0 12349 S+ 1000 0:02 | \_ python3 ./broadcast --url https://www.youtube.com/watch?v=53yEyj0mjfo LC_TERMINAL_VERSION=3.4.8 LANG=en_GB.UTF-8 LC_TERMINAL=iTerm2
12349 12358 12349 7451 pts/0 12349 S+ 1000 0:00 | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v=53yEyj0mjfo
12358 12359 12349 7451 pts/0 12349 RLl+ 1000 0:08 | \_ ffmpeg -i /dev/fd/63 -i /dev/fd/62 -c:v copy -c:a mp2 -b:a 192k -f mpegts - SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabaga
12359 12361 12349 7451 pts/0 12349 S+ 1000 0:00 | | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v=53y
12361 12364 12349 7451 pts/0 12349 R+ 1000 0:07 | | | \_ /usr/bin/python3 /usr/local/bin/yt-dlp --extractor-args youtube:player_client=android https://www.youtube.com/watch
12361 12367 12349 7451 pts/0 12349 Sl+ 1000 0:00 | | | \_ mbuffer -q -Q -m 52428800b SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R PWD=/home/pi/piwall2 LOGNAME=
12359 12363 12349 7451 pts/0 12349 S+ 1000 0:00 | | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v=53y
12363 12372 12349 7451 pts/0 12349 Sl+ 1000 0:00 | | \_ mbuffer -q -Q -m 5242880b SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R PWD=/home/pi/piwall2 LOGNAME=p
12358 12360 12349 7451 pts/0 12349 R+ 1000 0:00 | \_ tee /dev/fd/63 /dev/fd/62 SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R PWD=/home/pi/piwall2 LOGNAME=pi XDG_SE
12360 12362 12349 7451 pts/0 12349 S+ 1000 0:00 | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v=53y
12362 12366 12349 7451 pts/0 12349 Sl+ 1000 0:00 | | \_ mbuffer -q -l /tmp/mbuffer.out -m 209715200b SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R PWD=/home/p
12362 12368 12349 7451 pts/0 12349 S+ 1000 0:00 | | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v
12368 12370 12349 7451 pts/0 12349 SL+ 1000 0:00 | | \_ ffmpeg -re -i pipe:0 -c:v copy -c:a copy -f mpegts - SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R
12360 12365 12349 7451 pts/0 12349 S+ 1000 0:00 | \_ /usr/bin/bash -c ffmpeg -i <(yt-dlp --extractor-args youtube:player_client=android 'https://www.youtube.com/watch?v=53y
12365 12375 12349 7451 pts/0 12349 S+ 1000 0:05 | \_ python3 /home/pi/piwall2/msend_video --log-uuid 91QG3 SHELL=/usr/bin/zsh LSCOLORS=Gxfxcxdxbxegedabagacad LESS=-R PW