Last Updated 2 days ago
Filmmaking Dictionary: Number 6 / 6G-SDI
Definition
6G-SDI is a serial digital video interface with a nominal data rate of about six gigabits per second, commonly 5.94 Gb/s. It carries compatible digital video over a suitable connection, often a single 75-ohm coaxial cable with BNC connectors.
The ‘6G’ describes the interface’s data-rate class. It does not mean 6K resolution, six video channels or a six-gigabyte-per-second file transfer. Resolution, frame rate, sampling and signal mapping determine which picture formats a particular connection can carry.
Where It Fits
A common use is transporting supported UHD or 4K video at frame rates up to approximately 30 fps over one link. Exact capabilities depend on the equipment and the format being sent. A higher frame rate, different sampling format or other signal arrangement may need more bandwidth or multiple links.
The camera’s internal recording mode and its SDI output may differ. A camera can record one resolution while providing a lower-resolution monitoring signal. Read the output settings and receiving device’s supported formats rather than inferring compatibility from the recording menu.
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Checking a Signal Path
- Confirm that the source actually outputs the desired 6G-SDI format.
- Verify that every monitor, recorder, router or converter in the path accepts it.
- Use cable and connectors rated for the signal and intended run length.
- Check embedded audio and any required ancillary data as well as the picture.
Example on Set
A camera records high-resolution material internally and sends a UHD monitoring feed to video village. If an intermediate converter accepts only 3G-SDI, the chain may fail even though both the camera and final monitor support 6G. Every stage must accommodate the chosen signal.
A cable that works reliably for HD may fail at a higher data rate or longer run. Dropouts should prompt a check of format compatibility, connectors, cable condition and distance. The presence of matching BNC plugs alone is not enough.
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Frequently Asked Questions
Can 6G-SDI equipment also accept lower-rate SDI?
Many devices support several rates, but compatibility must be confirmed for the particular input or output.
Does a 6G-SDI cable compress the picture?
No. The cable transports the signal provided by the source. Any compression or conversion is performed by equipment, not by the passive cable.
Related Terms
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