BARB measurement of VOD 22 July 2012 Currently any viewing to programmes broadcast within the past 7 days is picked up and reported as time-shifted viewing, provided it takes place on a TV set. (BARB is at the first stage of installing meters in its panel homes to measure TV viewing on PCs and laptops). The main technique for measuring viewing is audio matching, which captures time-shifted viewing, so long as what is being viewed matches what was broadcast. This is the case whether a programme is recorded and being played back or is being accessed from a VOD service. One current limitation, however, is that it is not possible to distinguish between VOD viewing and play back of a recording using audio matching alone. Another is that, for VOD services in particular, if the commercials differ from those in the original broadcast (which is usually the case) viewing to VOD commercials cannot be picked up.