HDR (High Dynamic Range)
HDR lets a picture show brighter highlights, deeper shadows and richer colour than normal video.
HDR stands for High Dynamic Range. It is a way of making video that can show very bright spots and very dark shadows in the same picture.
Think of a box of crayons: normal video has a small box, HDR has a much bigger box with extra-bright and extra-deep shades.
Your player, the cable, anything in between and your TV all have to understand HDR for it to work.
Does the HDfury Vertex pass HDR?
YESYes, when the signal fits 18 Gbps. 4K60 HDR passes as 4:2:2 12-bit or 4:2:0; 4K60 4:4:4 only fits at 8-bit, so not at the 10 bits or more HDR normally uses (p.110).
How to use it with the Vertex:
- Use an HDR EDID, such as the default table (4K60 4:4:4 BT2020 HDR) or another 'HDR BT2020' table (p.8, p.15).
- Set SCALE to No Scaling/Passthru to pass the signal untouched (p.12).
- Check the HDR tag on the OLED Info page and the HDR 1 / HDR 2 pages (p.19, p.42).
- For a non-HDR display on one output, Auto Scaling can scale that output down while the other keeps HDR (p.103).
What it is
Dynamic range is the distance between the darkest and the brightest part of a picture. Normal video, called SDR, was designed for old tube TVs and has a limited range. HDR video stores much more brightness information, usually with 10 or 12 bits per colour instead of 8, and uses a wider colour range called BT.2020.
HDR is not one single format. The common ones are HDR10, HDR10+, Dolby Vision and HLG. HDR10, HDR10+ and Dolby Vision use the PQ brightness curve; HLG uses its own curve. The source tells the TV that the signal is HDR with small data packets called InfoFrames, and the TV then switches to its HDR mode.
HDR and 4K are different things. 4K is the number of pixels; HDR is how bright and colourful each pixel can be. A 4K picture can be SDR, and a 1080p picture can be HDR.
On the Vertex
The Vertex passes HDR through as long as the signal fits its 18Gbps (600 MHz) limit. At 4K60 that means 4:2:2 12-bit or 4:2:0; 4K60 4:4:4 is only possible at 8-bit, while HDR video is normally 10-bit or more (p.110). The default Custom EDID is a 4K60 4:4:4 BT2020 HDR table (p.8), and the preloaded list has HDR BT2020 tables as well as tables without HDR (p.15–16).
You can see HDR on the unit itself: the OLED signal line shows an HDR tag, and pages 3 and 4 (HDR 1 and HDR 2) show the HDR metadata (p.19, p.42). In the Windows GUI, the HDR INFOFRAME tab captures incoming HDR data, can send your own HDR data, or can remove it completely with Disable HDR (p.32).
When one output goes to a display that cannot take the full signal, the Vertex can scale that output down while the other output keeps the HDR signal (p.103).
Common questions
Is HDR the same as 4K?
No. 4K is the number of pixels. HDR is about brightness and colour. You can have 4K without HDR and HDR without 4K.
Why does HDR sometimes look darker than SDR?
HDR is graded so most of the picture sits at normal brightness and only highlights go very bright. On a display with limited brightness, such as many projectors, the picture can look dimmer than SDR, which TVs often show brighter than intended.
Can the Vertex pass 4K60 HDR?
Yes, as 4K60 4:2:2 12-bit or 4:2:0, within 18Gbps (p.110). 4K60 4:4:4 HDR at 10-bit or more needs more bandwidth than HDMI 2.0b has.
Do I need a special HDMI cable for HDR?
HDR itself does not need a special cable, but 4K60 HDR uses the full 18Gbps. HDfury advises 600 MHz/18Gbps certified cables for those formats (p.5).
- https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2390-11-2023-PDF-E.pdf
- https://www.avsforum.com/threads/hdr-worse-than-sdr.3168461/
- manual p.8, 15-16, 19, 32, 42, 103, 110