It can be difficult to estimate how long you will be able to record your IP cameras before your disk becomes full and the oldest recordings are overwritten to make way for new video.

We refer to this time as the recording duration.

You need to know (or estimate) the following:

The following section discusses each of these, and you can use our recording duration calculator at the end of this article.

This can typically be anywhere from 1 Mbps to 10 Mbps. A high-quality 25/30fps video stream at 1080p can take 5-10 Mbps, but it's possible to tune those settings to reduce the bitrate.

Depending on the quality of your camera's video compressor, it is often possible to reduce the bitrate to 3 Mbps with minimal quality loss - if you reduce the bitrate too much you'll notice visual artefacts in the output video feed, especially in scenes with a lot of movement.

The next step is to reduce the video resolution from 1080p to 720p, and/or reduce the frame rate to 15fps. This should allow you to reduce your camera bitrate to 1-3 Mbps.

The last factor is how much motion there is in a scene - the more motion there is, the higher the bitrate you'll need to maintain quality.

You would normally set this setting on your camera before adding it to your encoder. While adding the camera, you have the option to automatically set your quality/bitrate on your camera - make sure to disable this if you have set lower settings to help with your recording duration.

As you add more cameras to your encoder, this will proportionally reduce the recording duration you can achieve.

The larger the disk, the longer you can record. It is possible to add an additional USB recording disk to extend your recording duration.

You can use this Excel spreadsheet to enter your own details to calculate an expected recording duration: