EDID and capabilities

EDID

Extended Display Identification Data

Every source reads an EDID before it sends anything, and then believes it. On the Diva you decide what each of the four inputs is told.

EDID stands for Extended Display Identification Data, a VESA structure that has been in monitors since 1994 and in every HDMI display since. It lives in a small memory chip inside the sink and is read over the two wire display data channel in the cable, not over the video pairs. The base block is 128 bytes and holds the manufacturer, the model name and a set of timings. A CEA-861 extension block of the same size holds everything a television needs beyond that: the list of supported video formats, the audio formats and channel counts, speaker layout, colorimetry, HDR support and any vendor specific blocks such as the Dolby Vision one.

The important part is when it is read. Hot plug detect goes low and comes back, the source reads the EDID once, then sends the best format it claims support for. There is no negotiation afterwards and no second look. EDID is not a hint, it is the entire basis of the source decision, and anything it fails to mention will never be sent.

That becomes a problem once more than two devices are in the chain. A matrix, an amplifier and two displays of different vintages each contribute, and the honest combined answer is the lowest common denominator, so quality is lost for no good reason.

The five EDID modes on the HDfury Diva

The EDID section of the web server is where you choose what each source is told, and the RS232 and IP command is set edidmode with values automix, custom, fixed, copytx0 or copytx1.

COPY TX0 SINK

Use the EDID from the device connected at the TX0 output. The simplest choice when one display matters and the other is secondary.

COPY TX1 SINK

Use the EDID from the device connected at the TX1 output instead.

FIXED EDID

A 4K60 4:2:0 8-bit 300MHz 2-channel audio EDID, modest enough to give a picture in almost any setup and so the right thing to fall back on when you have lost your image.

CUSTOM

Define an individual EDID for each input, from 10 custom banks and 90 predefined tables. Use it when a games console and a disc player genuinely need to be told different stories.

AUTOMIX

Build a dynamic EDID from the real capabilities of the connected sinks, using one of five algorithms and fourteen forceable flags.

Per input assignment has its own command, for example set edidtableinp0 11. EDID Mode and EDID Table also appear in the OLED menu on the unit, which is what rescues you when an EDID change has left the display you were driving the browser from without a picture.

Getting an EDID in and out

DOWNLOAD ACTIVE EDID TABLES saves the EDID from any input or output as a file, which is worth doing before you change anything and is what support will ask for. UPLOAD EDID TABLES takes a file and a custom table number, and SEND EDID writes it into one of banks 8, 9 or 10, the three left empty for exactly this. Then click REFRESH and check the EDID rows in the INFO section to confirm the sources are seeing what you intended.

All glossary terms