How to use rviz without having problems with a freezing picture

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I'm trying to reconfigure some parameters (e.g. min_disparity) with rqt_reconfigure whilst using rviz to see how my point cloud changes. The point cloud moves because I'm playing back a video sequence. Unfortunately most of the time, the picture freezes after 10-20 seconds and rviz doesn't respond to any changes anymore. I can barely work on my parameters as I have to restart everything regularly. Has anyone else had similar problems using rviz and knows how to fix this problem? Tank you