Yet, within the H.264 framework there are other ways of structuring the compression process which do not involve chains. For example, each P frame may be generated by only referring to the I frame. (See Figure 4) This structure allows individual P frames to be discarded without affecting the decompression of other images in the GoP, but it is seldom used because it reduces compression efficiency. Closer examination though shows that any disadvantage is more than offset by gains in flexibility and the ability to employ other CCTV cost-reduction processes such as time lapse recording, ‘fading long term memory’ as well as independent control of display and recording rates. And, free from the constriction of P-chains, this kind of encoder can generate new I-frames at will, thus enabling video characteristics to be changed instantly and CCTV process latencies to be eliminated. Although still a tiny minority, products using this kind of structure do now exist. They include Geutebruck’s MPEG4CCTV and its new H264CCTV, an H.264 implementation that Basler (www.basler-ip.com) is offering in their latest generation of IP cameras, and one from Stretch Inc. which is fully supportive of such structures.