How to Face Swap Live on Stream (OBS and Twitch)

Most guides to face swapping on stream say: turn on the tool's virtual camera and add it in OBS as a Video Capture Device. With a browser face swap that fails, because OBS never lists the camera. Here is the route that works, what came out the far end of an RTMP stream, and the settings that decide whether viewers notice anything.

Why doesn't Facecam show up as a camera in OBS?

Facecam's camera lives inside Chrome, and OBS is a desktop app that only lists cameras installed on the computer. Live Face Swap is a real-time face swap that lets you look like anyone you choose: try it with your webcam on facecam.ai, then use it as a virtual camera in Google Meet, Zoom on the web, Discord in the browser and other sites in Chrome with the extension. Websites in Chrome see Facecam Virtual Camera; OBS, Zoom's desktop app and Discord's desktop app don't, unless you run Facecam for PC and Mac, which installs a camera with the same name. This guide uses the Chrome route.

So the swap reaches OBS as a picture: Chrome shows the swapped camera in a window, and OBS captures the window. It's one extra hop, but nothing heavy runs on your computer. The swap happens on our GPU servers, so you don't need the NVIDIA card that local tools like Deep-Live-Cam want.

How do I set it up, step by step?

1. 1

   Start the swap in Chrome

   Install the Facecam extension and sign in. In the popup, choose Face swap under Your look, then click a built-in face or upload a photo of the face you want. Live face swap is on every paid plan, from $10 a month.

2. 2

   Show the camera in its own Chrome window

   Open facecam.ai/webcam-test in a new window, click Start camera, and under Camera pick Facecam Virtual Camera. Turn Mirror off: it's on by default, and viewers would see any text behind you backwards.

3. 3

   Zoom the page to 150%

   Press Ctrl and + (Cmd and + on a Mac) three times. In a 1280-pixel-wide window the preview was 734 px wide at 100% and 1,102 px at 150%, more than our 960×720 camera, so OBS gets every pixel. Scroll until the whole picture shows.

4. 4

   Add the window to OBS

   On Windows, click + under Sources, choose Window Capture and pick the Chrome window. On a Mac with macOS 13 or newer, choose macOS Screen Capture, set Method to Window and pick Chrome; macOS asks you to allow screen recording for OBS the first time.

5. 5

   Crop to the video

   Hold Alt (Option on a Mac) and drag the source's red edges in until only the camera picture is left. Right-click the source, choose Transform then Fit to screen, or size it into a corner over your game.

6. 6

   Delay your mic and go live

   Add your microphone as usual and set its Sync Offset (next section). In Settings → Stream, choose Twitch, connect your account and press Start Streaming.

What do Twitch viewers actually see?

They see the swapped face and nothing of the setup. We streamed the OBS scene pictured at the top to a local RTMP server, the kind of ingest Twitch runs, and it received 31 seconds of 1280×720 video at 30 frames a second and 4.5 Mbit/s, with Kai's face in every frame we pulled out. No browser bar, no Facecam controls, no watermark.

Two numbers set expectations. The face updates about 17 times a second in our benchmark, so in a 30 fps stream most frames repeat the last swapped face; fine for talking, less so for fast head turns. And Facecam Virtual Camera is the size of your webcam picture, at most 1280 pixels wide (ours came through at 960×720). A 1280×720 stream matches it; a 1080p canvas only stretches the same pixels.

How do I fix lip sync?

Delay your microphone by about 220 ms. Your voice goes straight into OBS, but your face makes a round trip to a GPU first: in our benchmark a swapped frame took a median of 217 ms from camera to screen in Chrome on a computer (318 ms for the slowest 5%). OBS then takes the window once per frame, which adds up to 33 ms at 30 fps.

1. 1

   Open Advanced Audio Properties

   In OBS, choose Edit → Advanced Audio Properties, or click the gear next to your mic in the Audio Mixer.

2. 2

   Set Sync Offset to 220 ms

   Type it in the mic's Sync Offset (ms) box. A positive number delays that sound in your stream and recordings.

3. 3

   Check it with a clap

   Record 10 seconds of yourself clapping, step through the recording frame by frame, and raise or lower the offset in steps of about 30 ms until the sound lands on the frame where your hands meet.

How long can I stream, and what does it cost?

Live face swap uses 4.6 credits a minute, up to 6.4 at busy times: 276 to 384 credits an hour. A two-hour stream at the usual rate is 552 credits. It only uses credits while a page is using Facecam Virtual Camera, so close the Webcam Test window when you end the stream. Each start counts at least 3 minutes.

So Premium covers about one two-hour stream a week, and Pro about two. A two-hour stream every night (about 60 hours a month) is more than any plan includes, so live face swap suits a show night better than a daily stream.

What can go wrong on stream?

• Your real face for the first seconds. Until the new face is ready, Facecam Virtual Camera shows your normal camera, for up to 20 seconds the first time. Go live on a Starting Soon scene and switch only when the OBS preview shows the new face.
• A minimised Chrome window. Window Capture can't capture a minimised window. Put Chrome on a second monitor, or behind your game without minimising it.
• A black Window Capture on Windows. Open the source's properties and change Capture Method; OBS's own guide says BitBlt can help with some programs.
• A mirrored stream. The Webcam Test mirrors by default. If a poster behind you reads backwards in the OBS preview, turn Mirror off.
• Credits running out mid-stream. The swap stops when they do. The popup shows the time you have left; check it before a long stream.

Can I skip OBS?

Yes, with a browser studio. StreamYard and Restream Studio run in Chrome, so they list Facecam Virtual Camera directly: nothing to capture or crop. OBS earns the extra hop when you want game capture, overlays and your own encoder settings. For the other route into OBS, a VDO.Ninja link added as a Browser source, see face swap in OBS.

What didn't we test?

We ran OBS 30 on Linux with Screen Capture cropped to the Chrome window, not Window Capture on Windows or macOS Screen Capture, and streamed to our own RTMP server, not Twitch. The swap server replayed our GPU's real output, so the 217 ms delay comes from our benchmark on the real GPU, not this run. Our test machine had no graphics card and OBS's preview sometimes fell below 30 fps, so we report no CPU or smoothness numbers. We didn't test a Chrome window fully covered by a game; Chrome can stop drawing windows it thinks are hidden, so watch the preview.