You’ve probably seen the videos: a TV in a dark room, and the colors don’t stop at the screen. A fire scene washes the wall behind the TV in orange. An underwater shot turns the room deep blue. It looks like the picture is “spilling” into your space.

So what are the lights that go behind your TV and react to the screen?

They’re screen-sync TV backlights—usually an LED strip (or light bars) paired with a system that analyzes the colors on your display in real time and matches those colors on the wall behind your TV. The most common names you’ll see are TV backlight sync, immersion backlighting, or Ambilight-style lighting.

These are reactive TV backlights that mirror on-screen colors onto your wall for a bigger, more immersive feel. The “real” versions use either:

• a camera that watches the screen, or
• an HDMI sync box that reads the video signal directly.

Everything else is usually just decorative lighting.

What are they called?

Different brands use different terms, but they generally fall under:

• TV Backlight Sync Lights
• Immersion TV Backlighting
• Ambient TV Backlighting
• Ambilight alternative (a common way people describe the effect)

If you search any of those phrases, you’ll find the same category of products—just packaged differently.

Not all TV backlights that sync are the same

A lot of people get disappointed because they buy “TV lights” expecting the viral color-matching effect, but the product they bought isn’t actually reading the picture at all. In practice, TV lighting tends to fall into three buckets.

Static bias lighting is a simple strip that turns on with the TV and stays one color (often white or warm white). It’s great for comfort and eye strain reduction in dark rooms, but it won’t match the content.

Sound-reactive lighting reacts to audio in the room through a microphone. That can be fun for music and parties, but for movies it often looks random because loud sounds can trigger bright colors that don’t match what’s on screen.

True screen-sync lighting is what you’re after if you want the wall to mirror the movie or game. It samples the picture in real time and drives the LEDs to match what’s happening around the edges of the image.

How TV backlights react to the screen

Camera based TV backlights

Camera systems mount a small camera on or near the TV and “watch” the screen. Because they’re looking at the final image, they can work with almost anything you display, including the TV’s built-in apps. The tradeoff is that they can also be influenced by the room: glare, reflections, lamps, and sunlight can affect what the camera thinks it sees, which can lead to occasional color inaccuracies. Some people also dislike the look of a visible camera on a clean setup.

HDMI sync box TV backlights

HDMI sync systems read the video signal directly. An HDMI sync box sits between your playback device (like a console or streaming box) and the TV, then drives the LEDs based on the signal data. This approach is typically consistent because it’s not affected by ambient light in the room, and it keeps your TV bezel area clean with no camera on top.

The important limitation is simple: the sync box can only react to content that passes through it via HDMI. If you watch Netflix using the TV’s built-in app, an HDMI sync box won’t “see” that app unless you switch to an external streaming device.

Software based TV backlights

Software-based syncing usually means a computer is analyzing what it outputs and controlling lights accordingly. It can be very accurate, but it’s typically limited to PC usage unless you route your entire viewing setup through a computer.

How to choose the right TV backlights for your setup

If you want to avoid overthinking it, start with how you actually watch TV.

• If you mostly use built-in TV apps, a camera-based approach is often the most straightforward path to screen syncing.
• If you mostly use external HDMI devices (Apple TV, Fire TV, Roku, PS5, Xbox, Blu-ray), an HDMI sync box approach is usually the cleaner, more consistent experience.
• If you mainly want a soft glow for comfort, static bias lighting is the simplest and cheapest option.

Common compatibility issues to check before you buy

Screen-sync kits can be amazing, but most “it didn’t work” complaints come from mismatched expectations or missing one key spec. These are the big ones to check:

• Where your content comes from Built-in TV apps versus external HDMI devices
• Resolution and refresh rate Some setups are designed around 4K viewing at common refresh rates, while some gamers care about 120Hz and features like VRR
• HDR formats If HDR matters to your audience, be clear about what’s supported in your signal chain
• Audio routing Soundbars and AV receivers using ARC or eARC can change how you should wire devices
• Copy protection Streaming services may involve HDCP requirements across HDMI devices

How to get the viral look with TV backlights

The room matters more than most people think. If your setup looks weaker than the videos, it’s often not the kit—it’s the environment.

• Wall color Light walls reflect color better. Dark walls absorb light and reduce the effect.
• Spacing A small gap between the TV and the wall helps the glow spread smoothly.
• Brightness Slightly lower brightness often looks more cinematic and less distracting.
• Placement Clean, consistent strip placement around the edges gives the most believable “spill” effect.

A clean HDMI option for screen synced TV backlights

If you’re using external HDMI devices and prefer a camera-free setup, an HDMI sync kit is the style of solution designed for that workflow. One example is the DeckTok HDMI Sync TV Backlight Kit.

From the product listing, here are the practical details that matter for planning a setup:

• Designed for 55 to 65 inch displays
• Three-sided backlighting with the bottom strip not included
• RGB lighting
• App control and voice control
• App connectivity via 2.4GHz Wi-Fi and Bluetooth
• 12V and 20W power
• LED strip lifespan listed as over 30,000 hours
• One-year warranty and 30-day return window are listed on the page

If you want the look of a full four-sided frame of light, you can either choose a four-sided kit or supplement the bottom edge with a subtle bias light under the TV cabinet. Many living room setups do this and still get a strong immersive effect.

FAQs

What are the lights that go behind your TV and react to the screen called

They’re commonly called screen-sync TV backlights, TV backlight sync lights, or immersion TV backlighting. The defining feature is that the lights match the colors of what’s on screen rather than staying static.

Do these work with Netflix built into the TV

It depends on the method. Camera systems can usually sync built-in TV apps because they watch the screen. HDMI sync boxes only react to sources that pass through the HDMI box, so built-in TV apps typically require an external streamer if you want synced lighting.

Are cheap sync lights the same thing

Often not. Many low-cost “sync” products are sound-reactive and change based on volume, which can look random during movies and doesn’t reliably match the picture.

Do HDMI sync boxes add lag

Sync performance varies by device and settings, but HDMI-based approaches often feel more consistent than camera-based approaches because they read the signal directly rather than interpreting a camera feed. Always check supported resolution, refresh rate, and HDR modes for your specific setup.