It didn't work.
I changed the mtu to a value that made the messages about it being too small stopped. Here is the message log if that can help you help me.
main debug: creating new input thread
main: playlist item `udp/ts2://@239.255.255.245:4444'
main debug: waiting for thread completion
main debug: access `udp', demux `ts2', name `@239.255.255.245:4444'
main debug: looking for access module
main debug: probing 1 candidate
main debug: thread 4832 (input) created at priority 1 (src/input/input.c:326)
main debug: cmd=state old=10 new=1
main debug: playing at normal rate
access_udp debug: opening server=:0 local=239.255.255.245:4444
main debug: net: connecting to ':0@239.255.255.245:4444'
main debug: looking for network module
main debug: probing 2 candidates
ipv4 debug: IP_ADD_MEMBERSHIP multicast request
main debug: using network module "ipv4"
main debug: unlocking module "ipv4"
main debug: using access module "access_udp"
access_udp debug: no RTP header detected
main debug: looking for demux module
main debug: probing 1 candidate
main debug: demux2_New: 'udp/ts2://@239.255.255.245:4444' -> access='udp' demux='ts2' path='@239.255.255.245:4444'
main debug: looking for demux2 module
main debug: probing 1 candidate
ts2 warning: this does not look like a TS stream, continuing
main debug: using demux2 module "ts2"
main debug: using demux module "demux2"
ts2 warning: lost synchro
ts2 debug: 1692 bytes of garbage
ts2 debug: 1692 bytes of garbage
ts2 debug: 1692 bytes of garbage
etc, etc, etc