Razer Kiyo Pro Ultra A/V Sync & Latency Test

Razer Kiyo Pro Ultra A/V Sync Test: Measure Audio Offset for Streaming

A large-sensor webcam can look excellent and still need a specific sync correction on your machine. Kiyo Pro Ultra houses a 1/1.2-inch Sony STARVIS 2 sensor and an f/1.7 aperture lens, with Razer positioning it around large-sensor webcam capture and HDR support.¹ That physical size gives more low-light headroom, but it also means each frame carries more data through the camera processor and USB link. In practice, the Kiyo Pro Ultra should be tested in the same capture mode you plan to stream with, because HDR, Synapse processing, frame-rate, and exposure settings can all change the production offset.

Measure the Kiyo Pro Ultra in your actual capture configuration instead of relying on a generic offset range. The useful number is the one you get with your browser, USB connection, Synapse profile, lighting, and OBS frame-rate settings active.

Specifications¹

Connection and browser setup

Connect the Kiyo Pro Ultra to a USB 3.0 port before opening the test page. Grant camera and microphone permissions in Chrome when prompted; the browser Media Capture API is designed to request local audio and video devices from the platform.² USB video devices can also work through the system UVC driver without a proprietary camera driver.³

For the most accurate sync measurement, close Razer Synapse while you capture a clean baseline, then reopen it and configure the Kiyo Pro Ultra's Camera and Processing settings before testing your production setup. Razer's Synapse support workflow exposes those camera controls, including zoom and lens-distortion processing options, so the baseline and production runs should be treated as two different configurations.⁴

Synapse profile changes that shift the offset

Do not mix the clean baseline with the production profile when copying values into OBS. If the baseline is measured with Synapse closed and your stream uses Synapse HDR or lens processing, the baseline number will not represent the live setup. Run a second five-clap test after enabling the production profile, then use that second result for the stream. The difference between the baseline and production values tells you exactly how much Synapse processing adds to your video path, which is useful information when diagnosing future sync issues after software updates.

Common A/V sync issues with this model

Synapse image settings are the first things to check when Kiyo Pro Ultra readings vary. The product is designed around large-sensor capture and Synapse-driven customization, so your measured offset should match the exact profile you stream with rather than a default lab-style setup. Small changes to sharpness, saturation, or lens-distortion processing in Synapse can shift the video pipeline timing enough to move the offset by several milliseconds, which is why the production profile always matters more than a generic baseline.

The second common issue is changing light. The Media Capture and Streams specification notes that source conditions can change, such as when a camera switches to a lower frame rate because of low light, and that can affect the timing window used by the detector. Set the room to consistent, bright lighting before testing so the measurement reflects your capture pipeline instead of exposure changes. The Kiyo Pro Ultra's large 1/1.2-inch sensor gathers more light than smaller webcam sensors, which helps in dim rooms, but the camera's auto-exposure algorithm can still introduce frame-to-frame brightness adjustments that soften the clap transient if the lighting is uneven or slowly shifting.

Lighting changes that affect clap detection

In a dim room, add a desk lamp facing you before running the test. Brighter ambient light lets the sensor use a faster shutter speed, which means the clap motion appears in a shorter exposure window and creates a sharper luminance edge at the frame boundary. Sharper edges make individual clap detection more reliable and tighten the spread across five readings. Return to your streaming light setup after measuring and re-enable HDR if your production uses it.

What the test covers

The luminance transient detector samples each video frame drawn to a canvas element. At 60fps, each frame represents about 16.7 ms; at 30fps, each frame represents about 33.3 ms, so the detector has a smaller timing window when the capture path is running at 60fps.⁵ This makes the five-clap average more useful when your browser and OBS scene are both using the same frame-rate target.

Building on this, the tool reports the average offset across your five clap pairs. OBS lets you choose the resolution and frame-rate combination for a Video Capture Device source, so set that source to the same capture mode you use in your scene before copying the result into production.⁶ For the Kiyo Pro Ultra used as an OBS webcam source, enter the displayed OBS Audio Offset value in Edit > Advanced Audio Properties for your microphone; the Sync Offset column accepts a delay in milliseconds.⁷

Re-measuring after changing capture settings

The measured offset is specific to the capture configuration you tested with. HDR, Synapse processing settings, lighting, browser permissions, and OBS frame-rate settings can all change the production value, so re-run the five-clap test any time you change one of those settings. Update the OBS Sync Offset value to match the new measurement immediately, before starting a stream or recording session that uses the changed configuration. An outdated offset produces visible lip-sync gap from the very first minute of the session.

Independent review testing found that enabling HDR recording on the Kiyo Pro Ultra measurably reduces its frame rate, confirming the Synapse-controlled processing options change the camera's real-time performance rather than just its stored image settings.⁸ That heavier, configurable processing load is why this camera's typical offset runs higher than a basic fixed-focus, non-HDR webcam in this series.

Match the capture mode to your OBS scene before you trust the number. At 60fps each frame is about 16.7 ms and at 30fps about 33.3 ms, so the detector works inside a tighter timing window at the higher frame rate and the same HDR or Synapse change can read differently across modes. Set the Video Capture Device source in OBS to the exact resolution and frame rate you measured, then paste the offset into the Sync Offset column. Re-checking how enabling HDR changes the Kiyo Pro Ultra's frame rate after any single setting change keeps the first minute of your stream clean. Update the value before you go live.