Display Freezes at the receiver

[Beginner1]

I experience with UDP streaming from one PC to another across the LAN.
When I stream with the codec mp4v and stop in a certain moment, the display in the receiver freezes. If I resume the stream source, the display at the receiver synchronizes and resumes also.
On the other hand with the codec h264 stoping the source causes the display at the receiver to close completely (without a freeze).
1. What is the explanation for this difference at the receiver?
2. Can I control it by means of the VLC GUI or programatically by using a command line(at the receaiver and/or the transmitter)?

Thanks for any reference to my questions.
Regards
Izack