HDMI, DVI, and SDI all have corresponding non-compressed optical transceivers. The reason is very simple: non-compression means direct modulation of the original signal, no encoding, no frame dropping, and no delay. So when is this expense worth spending? Let's start with the three differences between compression and non-compression.
The first difference is delay
Network compression transmission must first be encoded and then decoded by H.264 or H.265. The end-to-end delay is usually tens of milliseconds to more than 200 milliseconds. Monitoring playback is enough, but live switching and real-time monitoring are unacceptable. Non-compressed optical transmission is point-to-point transparent forwarding, and the delay is generally within one frame. The feel of the director's screen switching is almost the same as that of the local monitor. This is a hard indicator for oral broadcasts and performance programs.
No chroma sampling, picture details are preserved
The compression link generally performs 4:2:0 or 4:2:2 sampling of chroma. The problem is exposed after the large screen is enlarged: the edges of subtitles and thin lines become blurry, and solid color blocks appear with gradient bands. The uncompressed link maintains 4:4:4 full sampling, and text remains sharp on the splicing screen. For exampleDVI non-compressed audio and video optical transceiverIt is a common choice for large screens on computer signals; when it is necessary to transparently transmit audio and EDID, compare HDMI and SDI series models.
Save money in three types of scenarios
- Signal interaction between studio and OB truck: any additional processing is a live broadcast risk
- Multi-screen splicing in the command center: multiple signal source links are inconsistent and the pictures are not aligned
- Display and detail review based on text and charts: Chroma sampling is a flaw
To sum up in one sentence: the compression solution buys flexibility, and the non-compression solution buys certainty. The signal running in the link is error-proof, so the optical fiber can be transmitted transparently as it is. If you are not sure, you can call EB-LINK technical support 0755-83179002 to help you judge.