Can HDMI 2.0 carry 4K60 at 10-bit?
4K60 bandwidth by bit depth and color format
Standard CTA-861 4K60 timing (VIC 97, 594 MHz pixel clock). Percentages show how much of each connector's capacity the signal uses.
| Format | Video Gbit/s | HDMI 2.0 | HDMI 2.1 | DisplayPort 1.2 | DisplayPort 1.4 |
|---|---|---|---|---|---|
| 8-bit RGB 4:4:4 | 14.26 | At the limit · 99% | Fits · 33% | Fits · 83% | Fits · 55% |
| 8-bit YCbCr 4:2:2 | 9.50 | At the limit · 99% | Fits · 33% | Fits · 55% | Fits · 37% |
| 8-bit YCbCr 4:2:0 | 7.13 | Fits · 50% | Fits · 17% | Not supported | Fits · 28% |
| 10-bit RGB 4:4:4 | 17.82 | Too much · 124% | Fits · 42% | Too much · 103% | Fits · 69% |
| 10-bit YCbCr 4:2:2 | 11.88 | At the limit · 99% | Fits · 33% | Fits · 69% | Fits · 46% |
| 10-bit YCbCr 4:2:0 | 8.91 | Fits · 62% | Fits · 21% | Not supported | Fits · 34% |
| 12-bit RGB 4:4:4 | 21.38 | Too much · 149% | Fits · 50% | Too much · 124% | Fits · 83% |
| 12-bit YCbCr 4:2:2 | 14.26 | At the limit · 99% | Fits · 33% | Fits · 83% | Fits · 55% |
| 12-bit YCbCr 4:2:0 | 10.69 | Fits · 74% | Fits · 25% | Not supported | Fits · 41% |
"At the limit" means the signal fits but uses almost all of the link. Use certified Premium High Speed (HDMI 2.0) or Ultra High Speed (HDMI 2.1) cables, and keep runs short or use fiber.
Why YCbCr 4:2:2 is the HDMI 2.0 workaround
HDMI sends YCbCr 4:2:2 in a fixed 12-bit container that runs at the same TMDS character rate as 8-bit RGB. So 8, 10 and 12-bit 4:2:2 all use 594 MHz, which just fits HDMI 2.0. YCbCr 4:2:0 halves the rate again, leaving plenty of room. The trade-off is color detail: fine colored text and single-pixel lines on an LED wall look softer in 4:2:2 and 4:2:0.
Does reduced blanking help?
A little, but not enough. CVT reduced blanking (RB v1) cuts the pixel clock from 594 to 533.28 MHz, but 10-bit RGB still needs 111% of HDMI 2.0. It does make a difference on DisplayPort 1.2: 10-bit RGB goes from 103% (too much) to 93% (fits).
Many TVs and projectors only accept the standard CTA-861 timing over HDMI. LED processors and media server outputs usually accept reduced blanking, so check the receiving device before you rely on it. More on reduced blanking.
4K60 CTA-861 timing (VIC 97)
Pixel clock 594 MHz · horizontal 135.000 kHz · 60.000 Hz
| Active | Front porch | Sync pulse width | Back porch | Total | Polarity | |
|---|---|---|---|---|---|---|
| Horizontal | 3840 | 176 | 88 | 296 | 4400 | Positive |
| Vertical | 2160 | 8 | 10 | 72 | 2250 | Positive |