High-efficiency NDI variant. Uses H.264 or H.265 compression instead of full NDI's lightly-compressed visually-lossless format — fits NDI signals onto low-bandwidth networks like Wi-Fi at the cost of slightly higher latency and CPU/GPU decode overhead.
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 (in HX3 and later) H.265 compression and lands at roughly 8-20 Mbit/s 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 with updated profile, lower latency than HX1 at the same bitrate. The current most-common variant in production cameras as of 2026.
- NDI HX3. H.265 (HEVC) based. Roughly half the bitrate of HX2 for the same picture quality, at the cost of higher decode CPU. 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. HX is the only NDI variant that fits.
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 ten 1080p60 sources, full NDI fits without compression 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 HX3 — software H.265 decode at 1080p60 across more than 4-5 sources hits a Ryzen 7 hard.