SDR (Standard Dynamic Range) – HDfury Vertex glossary
SDR is normal, non-HDR video: the picture standard used for TV, DVD and Blu-ray for decades.
SDR means Standard Dynamic Range. It is the normal kind of video that TVs showed long before HDR existed.
It is like a drawing made with a regular pack of pencils: it looks fine, but the brightest white and the richest colours are limited.
Most TV channels, DVDs, normal Blu-rays and many streams are still SDR.
Does the HDfury Vertex work with SDR, and can it convert HDR to SDR?
PARTLYPartly. SDR passes through normally, and Fixed EDID is a safe 4K60 4:2:0 8-bit SDR table. But the manual describes no HDR-to-SDR conversion; let your player do that.
How to use it with the Vertex:
- For a safe SDR fallback, set the EDID slide switch to Fixed EDID (p.8).
- Make sure Enable Custom HDR is off, or SDR programmes get an HDR flag and look wrong (p.32).
- Turn it off in the GUI, with RS232 #set hdrcustom off (p.51) or IR vertex_hdrcustomoff (p.77).
- For an SDR-only display, turn on HDR-to-SDR conversion in the player.
What it is
SDR video is made for a studio screen of about 100 nits (a unit of brightness) and uses the BT.709 colour range and a simple gamma brightness curve (ITU-R BT.1886). It usually uses 8 bits per colour.
An SDR signal carries no HDR InfoFrame, so the TV stays in its normal picture mode. When a TV shows SDR very brightly, that is the TV's own choice; the video itself does not ask for it.
Most HDR players can also turn HDR into SDR for older displays. That conversion is a kind of tone mapping and happens in the player or display, not in the cable.
On the Vertex
The Fixed EDID position of the EDID slide is a basic 4K60 4:2:0 8-bit SDR stereo table, meant as a safe fallback that gives a picture almost everywhere (p.8). The preloaded EDID list also has tables without HDR, for example 17 '4K60-444 600MHz All Sound' (p.15).
In the Custom HDR generator, 'SDR Luminance Range' is one of the EOTF choices (p.32). Be careful with Enable Custom HDR: it is stored and survives hotplugs and power cycles (p.32), and it replaces the incoming HDR data with your own (p.51). While it is on, SDR programmes are flagged as HDR too, so the display shows them wrongly. Switch it off in the GUI, with RS232 '#set hdrcustom off' (p.51) or the IR code vertex_hdrcustomoff (p.77).
The manual does not describe any HDR-to-SDR conversion inside the Vertex. If an SDR-only display needs SDR, let the player do that conversion.
Common questions
Why do my SDR programmes suddenly look washed out or too dark?
If Enable Custom HDR is on in the Vertex, every signal gets an HDR flag, including SDR. Turn Custom HDR off (p.32, p.51).
Can the Vertex convert HDR to SDR?
The manual does not describe that. The scaler changes resolution, chroma, colour space and bit depth (p.110), but it does not tone-map HDR brightness to SDR. Use the player's HDR-to-SDR setting.
Is SDR bad?
No. Well-made SDR looks very good. It simply cannot show the very bright highlights and wide colours HDR can.