Ndi Docs

NDI Docs

Context: $ARGUMENTS

Quick start

• Find an NDI API / feature / spec detail: → Step 2 (search --query <term>)
• Read the full section for a topic: → Step 3 (section --page <page> --id <anchor>)
• Grab a whole doc page: → Step 4 (fetch --page <name>)
• Prime cache for offline use: → Step 5 (index)

When to use

• User asks "what port does NDI use?" or "what's NDI|HX?" or "does NDI 6 support HDR?"
• Need to verify a wire-protocol detail before recommending config (mDNS 5353, TCP 5960, streams 5961+).
• Need the exact SDK-vs-Advanced-SDK feature matrix (routing, multicast, access-control, compressed passthrough).
• Need the official NDI 6 / HX3 / Agilex 7 feature list before claiming support.
• Need to cite the canonical docs.ndi.video URL.
• Integrating NDI with OBS → check DistroAV (not "obs-ndi" — that repo was renamed/forked).

Step 1 — Know the page catalog

The script only works against a fixed list of known docs.ndi.video pages plus the DistroAV GitHub README. Get the list:

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py list-pages

Common picks:

Read references/pages.md for the full catalog + use-cases.

Step 2 — Search first

When the user names an NDI feature / port / flag / function, search across all pages:

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py search --query "multicast" --limit 5

When you know the page, scope it (faster, less noise):

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py search --query "5960" --page sdk-port-numbers

Output format per hit:

--- <page>:<line> — <nearest heading>
<canonical URL with anchor>
<±3 lines of context>

Use --format json for machine-parseable output.

First run downloads the page; subsequent runs hit the local cache at ~/.cache/ndi-docs/.

Step 3 — Read one section in full

When a hit points to a specific topic and you want the whole block:

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py section --page sdk-port-numbers --id discovery

--id accepts an anchor id OR a heading keyword fallback.

Step 4 — Fetch a whole page

Rarely needed; search/section are almost always better.

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py fetch --page tech-ndi6

Pair with --format json for structured output.

Step 5 — Prime the cache (optional)

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py index

Fetches every known page into ~/.cache/ndi-docs/. Override with export NDI_DOCS_CACHE=/path. Clear: uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py clear-cache.

Gotchas

• NDI is proprietary. There is NO open-source libndi reimplementation. Every NDI-capable tool links against NewTek/Vizrt's binary libndi.so / Processing.NDI.Lib.dll / libndi.dylib that ships with the SDK installer. "Build NDI support from source" is not a thing.
• The SDK cannot legally be redistributed inside ffmpeg binaries. That's why ffmpeg's NDI support was removed from mainline (non-redistributable) and why OBS-NDI was renamed to DistroAV and must be installed separately — it dlopens the system-installed NDI runtime.
• Wire protocol uses THREE port families. mDNS discovery on UDP 5353 (standard Bonjour), messaging on TCP 5960, and each source opens streams starting at TCP/UDP 5961 and incrementing. Firewall rules must open 5353/udp + 5960-5999/tcp + 5960-5999/udp minimum, more if you host many sources.
• NDI full uses the SpeedHQ codec (Vizrt's proprietary DCT-based codec, ~15:1 compression, visually lossless on broadcast material). It is I-frame-only. Bitrate is roughly 100–250 Mbps for 1080p60.
• NDI|HX is H.264 or H.265 (the "HX" family — HX2 = AVC, HX3 = HEVC added in NDI 6). NDI|HX is NOT SpeedHQ; it's much lower bitrate (~8–20 Mbps) at the cost of latency (P/B-frames introduce encode/decode delay). Don't confuse SpeedHQ bitrates with HX.
• NDI 6 adds native HDR (PQ and HLG) and 10/12/16-bit pixel formats. Before NDI 6, HDR was unofficial / metadata-only. If a user says "NDI HDR", clarify they're on NDI 6+ runtime on both sender and receiver.
• Standard SDK is free for non-commercial use only. Commercial redistribution requires the Advanced SDK licence. Pricing is via Vizrt sales — not publicly listed.
• Advanced SDK unlocks routing, access-control (groups), multicast sending, compressed passthrough (send already-encoded streams without re-encode), custom frame sync, and a C++ wrapper. Standard SDK is send/recv/find only.
• NDI Bridge bridges NDI across subnets/WANs using TCP relay through a server. Required when mDNS can't traverse (LAN segmentation, VLAN isolation, site-to-site). Without Bridge, NDI is LAN-only.
• NDI Discovery Server is an alternative to mDNS — when mDNS is blocked on a hostile network, run a Discovery Server and point clients at it via env var NDI_DISCOVERY_SERVER=ip:port.
• DistroAV (the OBS plugin) is the successor to obs-ndi. The obs-ndi GitHub repo is archived/stale. Install DistroAV from github.com/DistroAV/DistroAV releases or via OBS's in-app plugin installer. It requires the NDI runtime installed separately (the SDK or the standalone Tools/Runtime installer).
• Fallback when docs.ndi.video is down: the DistroAV README (page=distroav) is hosted on GitHub raw and covers install + hotkey + common config.
• Cache is per-page only, not per-NDI-version. After a NDI release shifts spec pages, clear-cache then index.
• The script is stdlib-only — no pip install. Python 3.9+.

Examples

Example 1 — "What ports does NDI need open on the firewall?"

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py search --query "port" --page sdk-port-numbers

Example 2 — "Does NDI support HDR PQ?"

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py search --query "PQ" --page sdk-hdr
uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py fetch --page sdk-hdr

Example 3 — "What's the difference between the SDK and the Advanced SDK?"

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py fetch --page faq-sdk-vs-advanced

Example 4 — "What did NDI 6 add?"

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py search --query "NDI 6" --page tech-ndi6 --limit 10

Example 5 — "OBS + NDI setup steps"

uv run ${CLAUDE_SKILL_DIR}/scripts/ndidocs.py search --query "install" --page distroav

Troubleshooting

Error: unknown page: foo

Cause: Name isn't in the catalog. Solution: Run list-pages for valid names.

Error: urlopen error [SSL: CERTIFICATE_VERIFY_FAILED]

Cause: macOS Python missing certs. Solution: Run /Applications/Python\ 3.x/Install\ Certificates.command or set SSL_CERT_FILE. Don't disable SSL verification.

Search returns zero hits

Cause: Term doesn't exist on the selected page or docs.ndi.video moved the page. Solution: Drop --page to search all pages. Try broader query. Some details live in the DistroAV README rather than docs.ndi.video.

Cache stale after an NDI SDK release

Solution: clear-cache then index.

Reference docs

• Full URL catalog, wire-protocol summary, and SDK-vs-Advanced-SDK matrix → references/pages.md.