A packet-based video network including: two or more video data sources, each configured to launch video data packets onto the network as multicast data packets each associated with a multicast group identifier corresponding to that video data source; and a video data destination configured to receive and process video data from a video data source by joining a multicast group corresponding to that video data source, and execute a switching operation to switch from receiving video data from a first video data source to receiving video data from a second video data source by leaving a multicast group of the first video data source and joining a multicast group of the second video data source. The video data destination is configured to process video data corresponding to a video frame which, at end of a frame period, represents a most recently received video frame from the first video data source.