Mainstream and Substream - What is the difference?

When setting up your CCTV recorder, you'll notice the option to choose between mainstream or substream. But, what are mainstream and substream? These settings are used for viewing your DVR over LAN, WAN or Internet. Here is a detailed explanation of the two.

Mainstream and Substream

What is Main Stream?

This is the primary stream that affects data recorded to the hard disk drive and will directly determine your recording quality. The resolution denotes the image size and quality and is therefore very important and should not be overlooked. The frame rate (FPS - Frames Per Second) denotes how many frames are captured each second, with more frames being captured resulting in a smoother, more fluent and higher quality recording - 25FPS = “Real Time”. A higher resolution and frame rate will look best, however, be aware that it will use up more storage space on the hard disk drive. Setting a higher FPS will also affect your internet bandwidth when viewing a live stream. Users with limited internet speeds may suffer when using higher settings. The bit rate affects both of these settings and is usually dictated by a combination of the above. Lowering the mainstream settings is an effective way to increase available recording time.

What is Substream?

The sub-stream or extra stream is a second codec that runs alongside the mainstream. This allows you to reduce outgoing internet bandwidth without sacrificing your direct recording quality. The substream is often exclusively used by smartphone applications to live stream however some smartphone applications do allow the user to choose the mainstream too. Lowering the substream settings is often a common solution to no picture availability on a smartphone. Users with limited internet speeds may benefit most from this setting.