UVC, uncompressed video, & the USB-C question.
UVC isn't compression itself — it's the protocol that lets a USB device tell your computer "I'm a camera." But UVC can carry both compressed and uncompressed video, and that distinction is exactly what trips people up when they plug a webcam into a RØDECaster Video S and get nothing. Here's what's really going on inside that USB-C cable.
It's a handshake, not a codec.
UVC stands for USB Video Class. It's a specification — a rulebook — that says "if you make a USB device that produces video, follow these rules and any computer will recognize it as a camera, no driver install needed." It's the reason you can plug almost any modern webcam into a Mac, a Windows PC, or a Linux box and have it just work.
What UVC doesn't do is dictate how the video is encoded. The spec lets the camera and the host computer negotiate which format to use during the connection handshake. The camera says "I can do these formats..."; the host picks one based on bandwidth, software needs, and what it understands.
UVC is like the postal service: a system for moving packages. What's inside the package — a paperback book or a vacuum-sealed brick of compressed laundry — is a separate question. The RØDECaster Video S is picky about what's inside the package.
Two families. The compressed and the uncompressed.
When a webcam announces itself over UVC, it lists the formats it can produce. They fall into two groups:
The RCV-S has to mix your webcam's video with HDMI cameras and put it all on screen with zero perceptible delay. Decoding compressed video adds latency — sometimes a half-second or more. By accepting only uncompressed YUV, the RCV-S skips the decode step entirely and stays in sync. The trade-off is that you need a webcam that can produce uncompressed output, which not all of them can.
Uncompressed video is fat. The cable has to be fat too.
Compressed video exists for a good reason: uncompressed video is enormous. Here's the math, roughly, for 1080p video:
Look at that table: 1080p uncompressed at 30fps doesn't even fit through USB 2.0. That's why most consumer webcams default to MJPEG — it lets them claim "1080p over any USB port" by sending compressed video and letting the computer decompress it. Once you require uncompressed, you also need USB 3.0 or better. The RCV-S USB-C input is USB 3, so the bandwidth is fine — the question is whether your webcam can produce uncompressed output at all.
Three ways to find out before you buy.
- Read the spec sheet carefully. The phrases you want to see are "uncompressed video," "YUY2," "YUV 4:2:2," or "NV12." If the spec sheet only says "1080p H.264" or "MJPEG," that webcam cannot do uncompressed and won't work as a direct UVC input to the RCV-S.
- Check on a computer with the webcam tool. On macOS, open QuickTime Player → New Movie Recording and pick the webcam. On Windows, use OBS and add a Video Capture Device. The format dropdown will list every format the webcam offers. If "YUY2" or "NV12" appears, you're good.
- If your webcam is compressed-only, use a capture card. An HDMI-to-USB capture card (Elgato Cam Link 4K, Magewell USB Capture, etc.) takes any HDMI source and presents itself to the computer as a UVC webcam — in uncompressed mode. You can plug a webcam-class HDMI output (most webcams don't have one, but most cameras do) into the capture card and the capture card into the RCV-S USB-C input.
The general-rule list, not an exhaustive one.
RØDE keeps an official tested list on their support site (linked below). The general principle, gathered from RCV-S user reports and product spec sheets, is that these tend to work as direct UVC inputs to the RCV-S:
- Logitech BRIO 4K — explicitly supports YUY2 at 1080p30.
- Logitech C920 / C922 — supports YUY2 at 720p, but only MJPEG at 1080p. Works at lower resolutions.
- Insta360 Link — PTZ webcam, supports uncompressed.
- Anker PowerConf C300 — reported working.
- iPhone via RØDE Capture — RØDE's own free app sends uncompressed UVC over USB-C.
- Any HDMI camera + capture card — the safest universal path.
What tends not to work as a direct UVC input: cheap no-brand webcams, most laptop built-in cameras, and security/IP cameras that produce H.264 streams.
Before buying a specific webcam to use with the RCV-S, search "[webcam model] YUY2" or "[webcam model] uncompressed" and confirm at least one source says it offers uncompressed output. The official RØDE support article is the most authoritative source: help.rode.com · supported webcams.
One sentence to remember.
UVC is the rulebook. The RCV-S follows the rulebook strictly — it only accepts uncompressed YUY2 or NV12, not MJPEG or H.264 — so the question isn't "is my webcam UVC?" (almost all are), the question is "does my webcam offer an uncompressed mode?" (a much smaller subset).