When you start exploring Hikvision camera configurations, the terms “mainstream” and “substream” appear everywhere. Many users are confused about which setting to use for live view, recording, or remote access. In this technical guide, we will clarify the Mainstream vs Substream in Hikvision cameras, helping you optimize your video streams for performance, storage, and clarity. Drawing on deep technical specifications and practical deployment experience, this article explains the key differences and how they impact your security system.

Defining Mainstream (High-Definition) and Substream (Low-Bandwidth) in Hikvision Cameras

The mainstream, also known as the primary stream, is the default high-resolution video feed from a Hikvision camera. It uses the highest available codec, bitrate, and resolution—often 4K, 5MP, or 1080p—capturing every detail for forensic review. This stream is bandwidth-intensive, designed for local recording and analysis.

The substream, often referred to as the second stream or auxiliary stream, is a lower-resolution, lower-bitrate copy of the video. Common substream resolutions are CIF, QVGA, or 360p. It is purpose-built for multi-channel viewing, mobile apps, and minimizing network load when displaying multiple camera views simultaneously.

A typical Hikvision NVR or camera web interface allows you to configure both streams independently. The mainstream is scheduled for efficient local DVR/NVR storage, while the substream is optimized for remote live view over web browsers, VMS software, or iOS/Android applications. This dual-stream architecture is why you can view twenty cameras on one screen without network congestion, a direct result of understanding the mainstream vs substream hikvision balance.

The Technical Workflow: How Mainstream and Substream Coexist

In a Hikvision IP camera, the video encoder hardware processes the raw image sensor data twice—once for high resolution (mainstream) and again for low resolution (substream). The substream is generated from the same base image but downscaled to a target resolution like 640×480 pixels. This parallel encoding requires careful tuning of parameters such as video encoding (H.265+/H.264+), frame rate, and GOP (Group of Pictures) structure.

For optimal performance, you must match the substream bitrate to the network environment. If you set it too high, the substream will consume unnecessary bandwidth; too low, and the live preview will appear pixelated. A conservative guideline: set substream bitrate to 256 kbps for mobile access in outdoor Wi-Fi networks, and up to 512 kbps for local software playback. Conversely, the mainstream bitrate should be high enough to preserve details—typically 4 Mbps for 1080p H.265, scaling up for higher resolutions.

Key Differentiators: When to Use Mainstream vs Substream

Choosing between the streams depends on your immediate objective:

• Forensic Recording (Mainstream): Use only the mainstream for continuous recording on local NVR hardware. It ensures all license plates, faces, and details are captured in high