Magewell Pro Capture SDI 4K Plus

About this product

4K SDI sources do not all cable up the same way: some send the picture down one cable, others split it across two or four. The Pro Capture SDI 4K Plus is for broadcast and production teams who need one 4K capture card that copes with all three. It fits inside a computer, takes one 4K SDI signal, the kind used by broadcast cameras and vision mixers, and makes it available to software on that computer for recording, streaming or processing. It is a one-channel PCIe capture card that accepts 4K SDI however your equipment delivers it.

One signal, three ways to cable it

A 4K SDI picture can arrive on one cable or be split across several. The card captures one 12G-SDI signal by any of these connecting methods:

• Single-link 12G-SDI: the whole picture on one cable
• Dual-link 6G-SDI: the picture shared across two cables
• Quad-link 3G-SDI: the picture shared across four cables, as used by older 4K equipment

The card detects single, dual and quad link automatically, which saves you setting the mode when the source changes. It is one capture channel: the four connectors work together to carry one multi-cable signal. For two 4K SDI channels on one card, see the Dual SDI 4K Plus.

The connectors

There are four HD-BNC input connectors. HD-BNC is a smaller version of the usual BNC plug, used so that four fit on a low profile bracket. Each has its own range of signals:

• One accepts SD, HD, 3G, 6G and 12G-SDI
• One accepts SD, HD, 3G and 6G-SDI
• Two accept SD, HD and 3G-SDI

Four short HD-BNC to BNC cables (17.3 cm) are included, so you can plug in ordinary BNC cables without buying adapters. Because the inputs also take SD, HD and 3G-SDI, the same card suits HD sources today and 4K ones later.

Feeding a monitor as well

All four connectors on the card are inputs, dedicated to capture. If the signal also has to feed a monitor or other equipment, plan for an SDI splitter or a spare output on the source.

Picture, sound and frame rate

Input resolutions go up to 4096×2160 pixels, at 10 or 12-bit colour depth, with up to 8 embedded audio channels at 48 kHz, so sound arrives with the picture. Closed captions are available through the SDK. Capture frame rates go up to 144 fps, depending on PCIe bandwidth and image resolution. Ask us to confirm the frame rate for your source.

Processing done on the card

The card does part of the video work itself, before the pictures reach your software, which saves processor time on the computer. It provides:

• Two video processing pipelines with about 720 megapixels per second of processing bandwidth, and full 10-bit processing
• Scaling, cropping and de-interlacing, plus aspect ratio, colour format and frame rate conversion, so the software receives the picture in the shape it asked for
• On-screen overlay (OSD composition), where a graphic is laid over the picture
• Unlimited capture streams for the input channel, which lets you record in one program and monitor in another, and a latency of 64 video lines

Works with the software you already use

Magewell supplies drivers for Windows 10, Windows 11 and Windows Server 2016 to 2025, for Linux on x86, x64 and ARM (kernel 2.6.35 and above), and for Mac OS X 10.9 / macOS 10.12 and above. The card is then used through the standard capture interfaces of each system: DirectShow on Windows, V4L2 and ALSA on Linux, AVCaptureSession on macOS. That lets you use VLC, OBS, XSplit, vMix, Wirecast and other compatible programs, and an SDK is offered for developers.

Fitting it

It is a low profile PCIe x4 card, 140 × 68.88 mm without bracket, with a low profile bracket in the box, so it suits slim and compact PCs as well as towers. Maximum power is about 10.4 to 10.9 W depending on the cabling method. For two 4K SDI channels on one card, see the Dual SDI 4K Plus.