NVR Viewer — User Guide

1

Introduction

NVR Viewer is a live video viewer for NVRs, DVRs, and IP cameras on Windows. It lets you view your cameras without installing the manufacturer's software, which often includes advertisements, requires a cloud account, or simply doesn't provide a good experience on modern versions of Windows.

It works with devices that support ONVIF Profile S, the standard profile for live video streaming. In practice, most brands on the market support it, including Hikvision, Dahua, Uniview, and many generic or white-label devices built on the same chipsets. An NVR or DVR reports its individual video feeds as channels; this guide refers to them as cameras throughout, whether they come from a single IP camera or a channel on a multi-channel device.

This is a viewer, not a recorder. Recording, if you need it, is still handled by the NVR/DVR as usual. NVR Viewer does not manage recordings, events, alarms, or PTZ.

For Hikvision specifically: many Hikvision NVRs ship with ONVIF disabled by default. The app detects this automatically — if it cannot connect via ONVIF, it falls back to ISAPI (Hikvision's own HTTP API) to list the channels and construct the video URLs using standard RTSP. This fallback is specific to Hikvision; a device from another brand with ONVIF disabled simply won't connect.

2

Adding a Device

The app opens to the Devices tab. Click + Add and enter:

Name — the name used to identify the device in the list (for example, "Home" or "Office").
IP — the address of the NVR, DVR, or camera on your network.
ONVIF port — 80 by default; some devices use 8000 or 8080. If you're not sure, try 80 first.
User and Password — the device credentials. See the security recommendation below before using an administrator account.
HTTPS — enable this only if HTTPS is enabled on that port. If you're unsure, leave it unchecked (HTTP) and try.

Click Save.

3

Connecting

In the device row, click Connect. The app will:

Try ONVIF first to discover the device's cameras.
If the device is Hikvision and has ONVIF disabled (common out of the box), automatically fall back to ISAPI — no additional configuration is required.

If neither method works, the app shows the reason (such as rejected credentials or a wrong port). See Troubleshooting below.

4

Viewing Cameras

Once connected, the left panel lists the device's cameras. There are two ways to view them:

Individual view — select a camera and it fills the entire video area.
Mosaic — view all cameras at once in a grid. Drag and drop tiles to reorder them as you like; the order is saved.
Clicking the video in individual view returns to the mosaic. Optionally, require a double-click to switch between individual view and mosaic (in Settings) instead of a single click.
If a tile already has a live stream in the mosaic, opening that camera individually reuses the same connection instead of reconnecting — the switch happens instantly.

Mosaic columns — choose Auto, 2, 3, 4, or 5 fixed columns from the mosaic toolbar. This only fixes the number of columns, never the number of rows, so no camera is ever hidden by the chosen grid size; if there are more rows than fit on screen, the mosaic scrolls instead of shrinking the tiles.

Excluding a camera from the mosaic — right-click a camera in the side list and toggle it out of the mosaic grid. It stays fully available in individual view and in a floating window; the setting is saved per device and the camera's position in the order is preserved if you re-include it later.

Floating window — right-click a camera, either in the mosaic tile or the side list, and choose to open it in an always-on-top floating window. It has an independent connection to the camera, separate from the main window — handy for keeping an eye on a camera on a second monitor while using the app normally on the first.

5

Renaming Cameras

The name reported for each camera by the device (via ONVIF or ISAPI) is sometimes not very descriptive ("Channel 1", for example). To give it your own name, right-click the camera name — either in the side list or in its tile header in the mosaic — and choose Rename. The chosen name is saved locally for the device and used throughout the app until you change it. To restore the device-reported name, right-click again and choose Reset to device name.

6

Video Controls

With a camera open in individual view, the top bar provides these controls:

Control	What it does
Main / Sub	Switches between the high-quality stream (more bandwidth) and the lower-quality stream (lighter, useful with a mosaic of many cameras or on a slow network).
Full screen	Hides everything else. Press Esc to exit. Also available in Mosaic view.
Reconnect	Forces the stream to reopen if it appears stuck or frozen.
Snapshot	Saves the current frame as a JPEG image. By default, captures are saved to `Desktop\NVR Viewer - Captures`; the folder can be changed in Settings.

If a camera has no signal, its tile shows a clear message instead of an unexplained black screen.

7

Settings

On the Settings tab:

Start with Windows — launches the app automatically when you sign in to Windows.
Minimize to tray — closing the window keeps the app running in the system tray instead of fully exiting (useful if you leave it running in the background).
Opening a single camera switches it to the main stream — when enabled, opening a single camera while the mosaic is showing the secondary stream switches that camera to the main stream; returning to the mosaic restores the secondary stream.
Language — 10 languages available: English, Spanish, French, German, Italian, Portuguese, Dutch, Russian, Chinese, and Korean.
Capture folder — specifies where snapshot photos are saved. You can choose any folder or reset it to the default.

8

Security

This app only watches — it doesn't configure the device or delete recordings. For that reason, avoid using the NVR/camera's administrator account here. Instead, go to the device's web interface or local menu and create a new user with live-view-only permissions (an "operator" or "viewer" profile, depending on the manufacturer), with a different password from the administrator account, and use that account in the app. That way, if the password ever leaks, it can only be used to view live video — not to change the NVR's configuration or delete anything.

The app also limits the number of automatic reconnection attempts: if a stream never manages to authenticate, it backs off and eventually stops retrying instead of repeatedly sending failed login attempts to the device, which could otherwise lock the account.

Live video is never encrypted, even when the control channel uses HTTPS: the app does not implement RTSP over TLS, so video always travels over plain RTSP. HTTPS protects the control channel (credentials and configuration), not the video itself. Avoid exposing these devices directly to the Internet — use this app only on a trusted LAN or through a VPN.

If you use HTTPS: the device certificate

If you checked HTTPS when adding the device, the app saves the device's certificate the first time it connects. If a future connection presents a different certificate, the app rejects the connection instead of blindly accepting it. This can happen after a legitimate firmware change on your end, or if someone else on the network is impersonating the device.

If you changed the certificate intentionally (for example, after reinstalling firmware or generating a new certificate) and the app now blocks the connection, go to Devices, select the device, and click Forget certificate. The next connection will trust the certificate it receives and save it as the new certificate.

9

Troubleshooting

What you see	Likely cause	What to do
Wrong user or password (401)	Wrong credentials, or the user doesn't have the ONVIF service enabled on the device	Double-check user/password; on Hikvision devices, try anyway — it falls back to ISAPI
The device responded but no camera shows up	ONVIF poorly implemented in the firmware, or the user lacks "live view" permission	Try another user/profile on the device, or check the ONVIF port (80, 8000, 8080)
Camera listed but "no video URI"	That specific channel has no signal or a broken profile on the device	Check that camera/channel directly from the device
Video doesn't start	RTSP port (554) blocked by a firewall, different RTSP credentials than ONVIF, or the device requires UDP instead of TCP	Check the error message (usually points to the cause); check the firewall
The error message stops changing and mentions giving up after several attempts	The stream never managed to connect at all in several attempts — most often wrong RTSP credentials, but can also be a wrong port/URL or a firewall blocking the connection entirely	The app stops retrying automatically after a few failed attempts to avoid triggering an account lockout on the device. Check the underlying error text (shown right before the giving-up message), fix the likely cause — starting with credentials — and reconnect manually (reselect the camera).
Image doesn't appear but there's no error	The stream isn't standard H.264/H.265	Uncommon; may require changing the codec in the device's configuration
Not sure which ONVIF port to use	Varies by manufacturer/firmware	Try 80, then 8000, then 8080

If none of these suggestions solves the issue, the app's status/error text can be copied to the clipboard with one click and pasted when asking for help.

10

Supporting Development

If you find NVR Viewer useful and would like to support its continued development, you can donate via PayPal by scanning the QR code below.

Thank you for using NVR Viewer.