Reducing your surveillance bandwidth means lower storage costs and better remote monitoring. As such, professionals are always looking for techniques to do so, including improved codecs (MPEG-4 to H.264, H.264 Baseline to High Profile), VBR vs CBR modes, etc.
Rarely though do people look at using privacy masks for reducing bandwidth. Instead, privacy masks are typically used to prevent operators from seeing inside other people's homes and offices. Guidelines for using privacy masks, like this one from the UK government, focus on blocking surveillance from looking where it should not. The image below demonstrates a typical use of privacy masks to block out windows:
However, what if those privacy masks could be used to reduce bandwidth? In this test report, we try out privacy masks from Axis, Bosch, Panasonic and Sony to see if they could deliver savings. We apply masks and track bandwidth utilization before and after plus review the masking capabilities of each manufacturer.
[UPDATED 4/26/12: Based on user requests, we've added in test results for Arecont]