3G-SDI is a digital video interface (SMPTE 424M) transmitting uncompressed 1080p50/60 at approximately 3 Gbit/s over a single coaxial cable with BNC connector.
3G-SDI (Third Generation Serial Digital Interface) is a professional, uncompressed standard for transmitting digital video signals over a single coaxial cable. It is defined in the SMPTE 424M standard (first published in 2006, revised in 2012) and, along with the associated mapping standard SMPTE 425M, forms the third generation of the SDI family. The "3G" stands for the nominal data rate of approximately 3 Gbit/s.
On set and in the studio, 3G-SDI is the common connection between camera, monitor, recorder, wireless video transmitter, and video engineering. Unlike HDMI, the interface is designed for long, locking connections and is therefore more robust for professional continuous use.
| Parameter | Value |
|---|---|
| Standard | SMPTE 424M (Mapping: SMPTE 425M) |
| Data Rate (nominal) | 2.970 Gbit/s (or 2.970/1.001 Gbit/s) |
| Connector | BNC |
| Cable / Impedance | Coaxial cable, 75 Ohm |
| Typical Resolution | 1080p50 / 1080p60, 10 Bit, 4:2:2 |
3G-SDI distinguishes between two mapping variants: Level A transmits the 1080p signal as a direct, single data stream. Level B maps two combined HD-SDI streams (e.g., a dual-link signal or two independent signals). Both use the same physical 3 Gbit/s connection; however, the source and sink must be configured to the same variant, otherwise the image will remain black.
3G-SDI is the successor to HD-SDI (SMPTE 292M, approx. 1.5 Gbit/s) and uses the same connectors and coaxial cables, but doubles the bandwidth. This allows 1080p to be transmitted at full frame rate over a single line, which previously required a dual-link connection with two cables for HD-SDI. Above 3G-SDI follow 6G-SDI (approx. 6 Gbit/s) and 12G-SDI (approx. 12 Gbit/s) for 4K/UHD over a single cable.
As a cinematographer, I especially appreciate 3G-SDI for the reliable transmission of the camera feed to the monitors on set, without any loss of quality or latency. The robust BNC connection holds up reliably even under difficult shooting conditions and allows me to work precisely with the focus puller and other departments.
For me, 3G-SDI means the certainty that the image I see on my monitor is exactly what the camera is capturing – with no delay or compression artifacts. This reliability is crucial for precise directorial instructions and creative control over every shot.
3G-SDI equipment is more expensive to acquire than consumer alternatives, but the investment pays off in time savings and technical reliability. Failures or signal problems can ruin a shooting day, which is why this proven technology is a crucial component for a cost-effective production.
1. Zu welchem Department gehört „3G-SDI"?
2. Wie viele verschiedene Fachperspektiven bietet dieser Eintrag?
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