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HDMI

High-Definition Multimedia Interface

Standard: HDMI Forum Last updated: 2025-01-21

HDMI has been the dominant consumer A/V connector since the mid-2000s. The transition to HDMI 2.1 has been confusing because manufacturers can implement subsets of features. When buying a TV or monitor for gaming, verify specific feature support (VRR, ALLM, 4K@120Hz) rather than just checking for 'HDMI 2.1' branding.

Quick Specifications

Max Speed

48 Gbps

Max Power

0.275W

Pins

19

Reversible

No

⚠️ Common Confusion Points

  • HDMI 2.1 ports may not support all 2.1 features - manufacturers can pick and choose which features to implement
  • A 4K@120Hz display requires HDMI 2.1 - HDMI 2.0 maxes out at 4K@60Hz
  • Not all HDMI cables support all HDMI versions - look for 'Ultra High Speed' for 2.1
  • HDMI cables are not rated by version number - they're rated by speed (High Speed, Premium High Speed, Ultra High Speed)
  • VRR and ALLM are HDMI 2.1 features but some 2.0 devices support them via firmware
  • eARC requires HDMI 2.1 and a compatible cable - regular ARC works on HDMI 1.4+
  • Mini HDMI and Micro HDMI are physically different connectors with the same capabilities
  • HDMI ARC only works on specific labeled ports - usually HDMI 1 or 2 on TVs

Protocols & Versions

Protocol Data Rate Power Max Length
HDMI 1.4 (1.4) 10.2 Gbps — 15m at 1080p, 5m at 4K
HDMI 2.0 (2.0) 18 Gbps — 5m for 4K@60Hz
HDMI 2.0b (2.0b) 18 Gbps — 5m for 4K@60Hz
HDMI 2.1 (2.1) 48 Gbps — 3m passive for 48Gbps, longer with active cables
HDMI 2.1a (2.1a) 48 Gbps — 3m passive for 48Gbps

HDMI 1.4 Features

Audio Return Channel (ARC) 3D support Ethernet channel
Video support: 4K@30Hz, 1080p@120Hz, 3D

Cable requirements: High Speed HDMI cable

HDMI 2.0 Features

4K@60Hz HDR support 32 audio channels Dual video streams
Video support: 4K@60Hz, 1080p@240Hz, HDR10

Cable requirements: Premium High Speed HDMI cable

HDMI 2.0b Features

HDR10 HLG (broadcast HDR) Same bandwidth as 2.0
Video support: 4K@60Hz, HDR10, HLG

Cable requirements: Premium High Speed HDMI cable

HDMI 2.1 Features

Variable Refresh Rate (VRR) Auto Low Latency Mode (ALLM) Enhanced ARC (eARC) Quick Frame Transport (QFT) Dynamic HDR
Video support: 4K@120Hz, 8K@60Hz, 10K

Cable requirements: Ultra High Speed HDMI cable

HDMI 2.1a Features

Source-Based Tone Mapping (SBTM) All 2.1 features
Video support: 4K@120Hz, 8K@60Hz

Cable requirements: Ultra High Speed HDMI cable

Connector Specifications

Shape
trapezoidal
Pins
19 (2 rows)
Width × Height
13.9 × 4.45 mm
Depth
10 mm
Reversible
No

Electrical Specifications

Max Voltage
5V
Max Current
0.055A
Max Power
0.275W

Compatibility

Backwards Compatible With

  • DVI-D (video only, no audio)
  • HDMI 1.0-1.3

Forward Compatible With

  • HDMI 2.1

Can Adapt To

  • DVI
  • DisplayPort (active)
  • VGA (active)
  • USB-C (active)

Can Adapt From

  • DisplayPort
  • DVI
  • USB-C/Thunderbolt
  • VGA (active)

Common Uses

  • TVs
  • Monitors
  • Gaming consoles (PS5, Xbox Series X)
  • Streaming devices (Roku, Apple TV)
  • Laptops
  • Graphics cards
  • Blu-ray players
  • AV receivers
  • Projectors

Buying Guide

For 4K@60Hz HDR, get a Premium High Speed cable. For 4K@120Hz, 8K, or VRR gaming, you need an Ultra High Speed cable with HDMI 2.1 certification. Look for the holographic label on certified cables. Avoid extremely cheap cables for high-bandwidth uses. Cable length matters - longer cables may not support full bandwidth.

Data Sources