NDI HX

What it is

NDI HX is the high-efficiency variant of NDI. Where full NDI ships visually-lossless video at roughly 100-150 Mbit/s for a 1080p60 stream, NDI HX uses H.264 or (from HX2 onwards) H.265 compression and lands at roughly 11-16 Mbit/s (HX2) or 50-62 Mbit/s (HX3) for the same picture. The trade is the standard compressed-video compromise: smaller pipe, slightly more end-to-end latency, more CPU or GPU work to decode.

The variant chain

• NDI HX (legacy). The original H.264-based variant from 2017. Still supported by virtually every NDI receiver but no longer the default for new cameras.
• NDI HX2. H.264 or H.265 (HEVC) with an updated profile and lower latency than HX1 at the same bitrate — roughly 11-16 Mbit/s at 1080p60. The current most-common variant in production cameras as of 2026.
• NDI HX3. H.264 or H.265 (HEVC) at a higher bitrate than HX2 — roughly 50-62 Mbit/s at 1080p60 — for lower latency (under 100 ms on average) and a cleaner picture, at the cost of more bandwidth and decode work. Shipping in new product generations from PTZOptics, BirdDog, Lumens, Marshall and others.

When NDI HX is the right call

• Wireless cameras. A full-NDI stream saturates a clean Wi-Fi link. NDI HX over Wi-Fi is the normal way wireless PTZ cameras actually work.
• Large source counts on 1 GbE networks. Twenty full-NDI sources on a 1 Gbit/s switch saturate the link. The same twenty HX2 sources fit comfortably with headroom.
• Mobile broadcast / news crews. Bonded-cellular uplinks have a hard bandwidth ceiling. Only the lower-bitrate HX variants (HX, HX2) fit.

When to keep full NDI

• Production master switching where keying / chroma matter. H.264/H.265 artefacts show up in colour-keyed feeds. Full NDI is the broadcast-safe choice.
• Low-latency operator workflows. HX adds ~40-100 ms over full NDI at typical settings. For wall-driven operator UX, full NDI on wired networks usually wins.
• Wired 1 GbE+ networks with modest source counts. Below about six 1080p60 sources per 1 GbE link, full NDI fits without the HX decode overhead and gives the cleanest picture.

What this means for video walls

A video-wall controller that accepts NDI sources should accept HX, HX2 and HX3 in addition to full NDI, decode them all through the same composer pipeline, and expose the bitrate / variant per source so the operator can spot the bandwidth-hungry sources during commissioning. Hardware decode (NVDEC on NVIDIA, Quick Sync on Intel) is effectively required for H.265 sources (HX2 or HX3) — software H.265 decode at 1080p60 across more than 4-5 sources hits a Ryzen 7 hard.

Related terms

• NDI (Network Device Interface)
• AV over IP
• IPMX
• SRT (Secure Reliable Transport)