What is DTD?

In plain language

Most of an EDID is a checklist of supported formats. A Detailed Timing Descriptor is different: it describes a single timing exactly — active pixels, blanking, sync widths, pixel clock. The first DTD in an EDID is the display's preferred timing, its native mode.

Why it matters in your setup

Sources lean on the preferred timing. It is what a PC picks as the recommended resolution and what many players default to. If the DTD is lost or replaced while EDID passes through a chain, the source may fall back to a generic mode, and you end up with a picture that is technically valid but not the one the panel wants.

This matters most for projectors and for PC use, where a non-native timing shows up immediately as soft text or unexpected scaling.

What the DR HDMI 8K does with it

DR HDMI 8K firmware 1.4 added the ability to retain DTD data, so the display's own detailed timings survive an EDID copy or an AutoMix operation instead of being dropped. You can also download the active EDID from either side and inspect it.