This is because the ASA will block it if the security level is lower, by default, you can send traffic to lower security levels but not the other way arround, from the config, I asume that the tandberg is sending the RTP stream and the other equipment is recieving it suscesfully, however, the tandberg is not getting video.
If that is the case, could you please tell me the IP address of the Tandberg and the other video endpoint? Have you tried to edit the ACL with the IP address of the other endpoint in order to log the packets and see if they are getting to the ASA or not?
Thanks and regards,
espereir