An apparatus includes a network interface and a processor. The network interface is configured to communicate over a communication network. The processor is configured to receive (i) data, including a medical parameter acquired as a function of time, and (ii) a selection of one or more time intervals of interest within the time period. The processor is further configured to compress a first portion of the data, which is within the selected time intervals, at a first resolution, and compress a second portion of the data, which is outside the selected time intervals, at a second resolution, which is coarser than the first resolution. The processor is additionally configured to transmit the compressed first and second portions of the data, via the network interface, over the communication network.