HD Lite can be achieved by any combination of several techniques. "Rate-shaping" dynamically adjusts allocated bit rate for each of a set of TV-channels, based on an allocation-policy (which can come from realtime video-analysis or an operator-specified program weighting.) Rate shaping allows a set of channels to be transmitted with less bandwidth, based on the statistical observation that not all channels display the same level of motion-activity at a given instant of time (or the period of observation.) "Downsampling" reduces the spatial (horizontal and/or vertical) resolution of the TV-program, reducing the TV-signal's pixel-rate, and therefore its bandwidth requirements. Thus far, customers have reported downsampling on "1080i" signals only; 1920x1080i can be downsampled to 1440x1080i or 1280x1080i, with a corresponding reduction in transmission bandwidth. In contrast, over-the-air (ATSC) broadcasts of 1080i are fixed at 1920x1080. Temporal (frame-rate) reduction has not been attempted yet, as it unacceptably changes the character of motion video sequences.