Logitech MX Brio 4K A/V Sync & Latency Test

Logitech MX Brio 4K A/V Sync Test: Measure Audio Offset for Streaming

Start with the production settings you actually use, then measure the MX Brio from that same state. MX Brio is Logitech's 4K Ultra HD collaboration and streaming webcam, with 4K at 30fps or 1080p at 60fps from its image sensor.¹ Logitech describes AI image enhancement, Show Mode, and advanced controls through Logi Options+ or G HUB, so disable variable framing or presentation features before you measure a stable A/V offset.

This tool compares local video and audio transients after the browser grants the requested media tracks, then reports the offset for the resolution and device path you actually used. Use the five-clap result from your own USB topology and app settings rather than a generic MX Brio offset figure.

Specifications²

Connection and browser setup

Disable Show Mode and any variable AI framing features before opening this page. Those features can change crop, lighting, or enhancement behavior between claps, which makes the five readings less consistent. The MX Brio's AI image enhancement pipeline can also adjust sharpness and noise reduction on a per-frame basis, so a variable scene with moving hands and changing light creates a less predictable processing load than a static scene.

After granting camera and microphone access, verify the preview resolution and frame rate before you start; the reported offset applies to that exact browser stream.³ Connect the MX Brio to a USB port with enough available bandwidth for the resolution you want to test. USB bandwidth is shared across the host controller and device tree, so another high-bandwidth device can change what the camera can sustain during the test.⁴

The MX Brio is a USB video device, and Windows can use the system UVC driver for compliant USB video devices instead of a Logitech driver.⁵ Close conferencing apps or other camera-control software before testing if the preview stutters, drops frames, or shows a different resolution than expected.

Matching the production stream profile

Keep the browser preview on the same resolution and frame rate you intend to use in OBS or Streamlabs. A 4K measurement can differ from a 1080p/60 measurement because the camera, USB path, and browser processing path are no longer identical. If you switch between 4K and 1080p during the week, measure both profiles and label the OBS values separately.

Common A/V sync issues with this model

AI image enhancement is the main feature to control on the MX Brio. With variable enhancement active, processing can change from frame to frame, which can widen the spread between clap readings. Disable Show Mode and variable framing features before testing so the camera stays in a consistent state. The MX Brio's 4K sensor captures significantly more data per frame than a 1080p camera, and when AI enhancement processes each frame at full resolution, the per-frame processing time can vary depending on scene complexity, introducing small timing fluctuations that show up as wider spread across your five clap measurements.

Frame drops are the other common issue to watch. They can come from USB bandwidth pressure, another app holding the camera, or power-management behavior on the host. The five-reading average helps expose inconsistent sessions, but it cannot turn a dropped-frame clap into a reliable timestamp. If one reading sits far outside the cluster, close camera-control software, keep the same USB topology, and rerun the test.

Outlier readings and how to handle them

Outlier readings usually mean the clap was not measured under the same conditions as the other four. A dropped frame, a sudden exposure change, or another app changing the camera mode can move one timestamp away from the rest. Retest before copying the offset into OBS or Streamlabs when the readings do not cluster tightly. Comparing the spread between your five readings against the average tells you whether the outlier pulled the final number away from the true offset for your setup.

What the test covers

Five clap pairs produce an averaged millisecond offset and a direction label. The value applies to the exact conditions you measured: same resolution, same machine load, same USB port, and same camera settings. Changing any variable requires re-measurement. Because the MX Brio supports multiple resolution and frame-rate combinations, each combination can produce a different offset; a 4K/30fps measurement should not be applied to a 1080p/60fps production scene because the camera's internal processing path changes between modes.

OBS source timing is based on audio and video timestamps, so the sync value you enter should match the measured browser stream conditions as closely as possible.⁶ Enter the value in OBS under Edit > Advanced Audio Properties > Sync Offset (ms) for your microphone source, then record a short test clip to verify the clap sound aligns with the visible hand impact.

Rechecking after Logitech app changes

Re-running the test after changing Logi Options+, G HUB, or camera firmware settings confirms whether the new settings changed the offset. Open the relevant Logitech app after each update, check the MX Brio image and framing features, disable any variable features you do not want during production, and run the five-clap test again to get the updated offset. A before-and-after comparison of the two measured values quantifies exactly how much the Logitech software change shifted your pipeline, which helps you decide whether the new settings are worth the sync trade-off.

Logitech markets the MX Brio around AI-powered face-based image enhancement that runs continuously as you present¹, a heavier per-frame processing load than a fixed-focus, non-HDR camera in this series carries. Expect the MX Brio's typical offset to sit closer to other active-processing cameras than to the C920x's minimal-pipeline baseline.

Because the offset only holds for the conditions you measured, keep in mind the 4K-versus-1080p60 offset gap on the MX Brio and start from the production state you intend to keep. The value you capture applies to the exact resolution, machine load, USB port, and camera settings you used, so re-running after a firmware or app change protects the number you paste into OBS. A 4K/30fps reading should never be applied to a 1080p/60fps scene, because the MX Brio's internal processing path differs between those modes. Keep the before-and-after numbers together so you can see how much a single setting shift moved your pipeline. Measure once per mode.