Some of the newer DVRs on the market offer a feature called either a substream or a dual stream. A sub stream is used for viewing your DVR over the LAN or WAN when the resolution or frame rate of the recorded video is too high for the available bandwidth. For example, if your DVR was recording at 4CIF (or D1) resolution which is 704×480 in realtime (30fps), that would provide you with some exceptional recorded footage that would be both 4 times larger than the average CIF (360×240) recording and in realtime. Unfortunately, in most cases you would not be able to remotely view the video with fluid motion over the internet because there would not be enough available up bandwidth coming from the DVR location. In this case you would benefit from a sub stream that would be set at a lower resolution like CIF (360×240). This would allow you to have a high quality recording, but still be able to view fluid video over the internet.