CCTV Flicker and Rolling Bands Under LED Lights: The 50 Hz Fix (India)

India's grid runs at a National Reference Frequency of 50.000 Hz, so tube lights on chokes and many mains-driven LED fittings ripple at about 100 Hz. A camera left on 60 Hz/NTSC catches that ripple as rolling bands. The fix: set Anti-flicker (Dahua/CP Plus), Video Standard (Hikvision) or Exposure Mode (Uniview) to 50 Hz.

Verified against

• CERC, Order in Suo-Motu Petition No. 2/SM/2025, 29 Mar 2025, quoting Regulation 30(1) of the CERC (Indian Electricity Grid Code) Regulations, 2023 (PDF, p. 6).
• U.S. DOE / Pacific Northwest National Laboratory, Characterizing Photometric Flicker, Feb 2016 (PDF, pp. 5–6).
• Hikvision, Network Camera User Manual (Baseline), V5.6.5, 28 Dec 2023, UD19347B-C (PDF, pp. 104–108).
• CP Plus, IP Camera User Manual, Version 2.01, Q-series (PDF, §4.3.1.4, p. 24–25); CP Plus, Network Camera Web Operation Manual, Version 1.0.3, LQ-series (PDF, §5.1.1.a.ii, pp. 27–28).
• Dahua, Network Camera Web 3.0 Operation Manual, Version 1.0.1, §5.1.1.2 (copy hosted by distributor LSC: PDF, pp. 32–33).
• Uniview, How to set Exposure? (3 Jul 2019, PDF) and How to Troubleshoot If a Uniview Camera Has Strobe Problem? V1.1, 26 Sep 2023 (PDF).
• Prama, PT-NC120D3-N(D2) product page (spec table on the page).
• Checked 7 Oct 2026.
• Not verified: Prama's menu path (its product page links a datasheet only via a login page, no open manual); any vendor-printed 50 Hz shutter value; firmware builds (manuals give document versions only); flicker data for specific Indian LED fittings.

Anti-flicker setting by brand

Related device-level defaults from the same documents:

Why bands appear: shutter vs 100 Hz light

Per DOE/PNNL, for many traditional sources the dominant flicker frequency "is simply twice the input-line-voltage frequency": 100 Hz on 50 Hz power. For LEDs, flicker "is generally determined by the LED driver" and its frequency "can vary significantly", so two same-wattage LED high-bays can behave differently. Electronically ballasted tube lights modulate at 20–60 kHz, far too fast for a camera to see.

A CMOS sensor reads rows one after another. If each row is exposed for only part of a 10 ms light cycle, rows caught at bright and dim moments differ: horizontal stripes. If frame timing is not locked to the light, they drift: the "rolling band".

Our arithmetic, not a vendor statement: at 100 Hz the light cycle is 10 ms, so an exposure of whole cycles (1/100 s, 1/50 s) averages the ripple out. Uniview's strobe guide suggests a manual 1/120 s without naming a mains frequency; that is one cycle of 120 Hz ripple (60 Hz mains). On 50 Hz mains the equivalent is 1/100 s. No vendor document we checked prints 1/100 s.

Fix in four steps

1. Check the video standard first. CP Plus cameras ask for region and Video Standard (PAL/NTSC) at initialisation (Q v2.01, LQ v1.0.3); the Q manual also puts it under System > General > Basic, noting "Some devices have default PAL video standard". Choose PAL/50 Hz.
2. Set anti-flicker to 50 Hz at the path in the table. Avoid "Outdoor" indoors: in the CP Plus and Dahua manuals it is the mode that unlocks gain or shutter priority instead.
3. Uniview only: its strobe guide (V1.1) suggests, in order, an NVR capture mode at @20/@25/@30 fps, Exposure Mode Indoor 50Hz, then a manual shutter (it prints 1/120 s; on 50 Hz mains our arithmetic gives 1/100 s). With WDR on, lower the level and enable "Suppress WDR Stripes".
4. Recheck by day and by night. Uniview says strobing appears especially "when the indoor light is on during daytime". After dark, day/night switching changes exposure, so check again on the night shift.

Where brands differ

• Hikvision vs Prama. Hikvision files 50/60 Hz under Video Adjustment as "Video Standard", not Exposure. Prama's spec page lists only "anti-banding" and "50 Hz: 25 fps". A similar field is likely but undocumented; confirm on your firmware.
• CP Plus vs Dahua. The anti-flicker table text is almost word for word the same in both. The path differs by CP Plus line: Q-series uses the settings icon > Camera > Image > Exposure; LQ-series uses Setting > Camera > Conditions > Exposure, as Dahua Web 3.0 does.
• Uniview. In Uniview's exposure how-to, the 50 Hz choice is an Exposure Mode ("Indoor 50Hz"), not a separate anti-flicker field, so picking it replaces Automatic/Manual exposure.

What breaks in a factory

• Mixed lighting in one frame. A bay with new LED high-bays next to old choke tube lights or sodium lamps on magnetic ballasts can band in one part of the image only. A poor LED driver may still stripe.
• Motion blur trade-off. Anti-flicker modes limit the shutter (Uniview: "limiting shutter frequency"). Fast parts (spindles, conveyors, press strokes) blur more at 1/100 s than at 1/1000 s. For counting or reading fast motion, more light beats a faster shutter; see resolution and lens for a factory floor.
• Analytics see bands as motion. A rolling band changes pixels every frame, so motion-based analytics can read a stopped machine as busy. Fix flicker before you run analytics on existing CCTV.
• Night shifts. The fittings become the only light. For IR and low-light settings, see night and low-light cameras on a shop floor.
• Grid frequency drift does not matter. The IEGC band is 49.900–50.050 Hz, and CERC's order records three days in August 2024 with peaks of 50.33–50.39 Hz. A 50 Hz anti-flicker setting is still the right choice.

For other symptoms, start at the CCTV troubleshooting guide for factories. For stream URLs by brand, use the RTSP and ONVIF cheat sheet for Indian brands or the CP Plus RTSP and ONVIF page.

When to call the installer / what to ask the vendor

Call the installer if bands persist after 50 Hz is set on every camera, or if the setting is greyed out. Ask the vendor: Does this firmware expose anti-flicker or video standard for this model? Is the camera region-locked to NTSC? Does the NVR override the camera's frame rate?

Where Mama fits

Mama reads a factory's existing cameras over RTSP/ONVIF and tells the owner, in plain language, where machines sat idle. That reading is only as good as the picture: a rolling band can look like activity, so correct anti-flicker settings come first. Leave an email or phone in the form below.

FAQ

Should I set my CCTV camera to 50 Hz or 60 Hz in India? 50 Hz. Indian grid regulation fixes the National Reference Frequency at 50.000 Hz (IEGC 2023, Reg. 30(1)). In Hikvision's manual, 50 Hz goes with PAL. CP Plus manuals ask for the video standard (PAL/NTSC) at initialisation; choose PAL.

Why do horizontal lines roll across my CCTV picture only under LED lights? Choke tube lights and many mains-driven LED drivers ripple at twice mains frequency (100 Hz in India); DOE/PNNL notes LED flicker frequency varies by driver. By our arithmetic, an exposure that is not whole 10 ms cycles catches the ripple row by row. Anti-flicker at 50 Hz limits the shutter to avoid this.

Does anti-flicker make the image darker or blurrier? It limits how fast the shutter can go, so fast-moving objects can blur more. Per the CP Plus and Dahua exposure tables, in 50Hz mode the camera still adjusts exposure automatically to the ambient light, so it should not by itself leave the picture dark.

My camera flickers only at night. Is it the same problem? It can be: at night the fittings are the only light source, so any light ripple is no longer diluted by daylight. Uniview also notes that WDR can cause strobing; lowering WDR or enabling "Suppress WDR Stripes" may help on Uniview models.