HDMI: Digital video/audio connector for uncompressed HD/4K signal transfer — standard on consumer cameras and monitors.
Technical Details
HDMI 2.1, the current specification, achieves 48 Gbit/s compared to 18 Gbit/s for HDMI 2.0. The connector uses 19 pins in four different form factors: Type A (Standard), Type B (Dual-Link, rarely used), Type C (Mini), and Type D (Micro). Cable length is limited to 15 meters at 1080p and 5 meters at 4K due to signal attenuation. Variable Refresh Rate (VRR), Auto Low Latency Mode (ALLM), and Enhanced Audio Return Channel (eARC) are among the advanced features.
History & Development
Seven electronics companies developed HDMI in 2002 as a successor to analog interfaces, with the first specification, 1.0, appearing in December 2002. HDMI 1.3 introduced Deep Color and lossless audio formats in 2006, and HDMI 2.0 brought 4K support at 60fps in 2013. The current version, 2.1, was released in 2017 and enables 8K resolutions. Over a billion HDMI-enabled devices are sold annually.
Practical Use in Film
Modern film cameras like the RED V-Raptor or ARRI Alexa Mini LF utilize HDMI 2.1 for live monitoring on external recorders and director's monitors. In "Avengers: Endgame," HDMI links were used for real-time transmission of LED wall content. External recorders such as the Atomos Ninja V+ receive ProRes RAW streams directly from the camera via HDMI. The single-cable approach significantly reduces cabling effort compared to SDI installations.
Comparison & Alternatives
SDI (Serial Digital Interface) remains dominant in professional environments due to its support for longer cable runs up to 300 meters and its use of more robust BNC connectors. DisplayPort offers higher bandwidth but is primarily used in the computer sector. USB-C with DisplayPort Alt Mode is establishing itself as a mobile alternative. While HDMI dominates consumer hardware, broadcast productions continue to rely on SDI infrastructures. Thunderbolt 4 competes in high-end workflows with its 40 Gbit/s throughput.
Current News
The new Atomos recorders Ninja TX Go and Ninja RAW demonstrate the increasing specialization of HDMI-based recording solutions. While the TX Go is limited to 6K 30p recording via HDMI and omits SDI connections, the Ninja RAW focuses entirely on HDMI RAW recording up to 6K. This development underscores HDMI's growing importance as the primary interface for high-resolution video transmission in professional production.
Current News
Current external recorders like the Atomos Ninja TX Go utilize HDMI inputs for recordings up to 6K 30p and support modern codecs like H.265 for efficient file compression. Newer models offer advanced features such as camera control via USB-C connections. However, some more compact variants forgo SDI ports and wireless timecode synchronization in favor of portability.