obs-streamer-tools-plugin/third_party/livekit/README.md

# LiveKit client-sdk-cpp redistribution notices

This plugin links and **redistributes** prebuilt binaries from
[`livekit/client-sdk-cpp`](https://github.com/livekit/client-sdk-cpp) — the
`liblivekit` / `liblivekit_ffi` shared libraries that ship next to the plugin
module — so the SDK's licence and notice files ship with it.

`LICENSE` and `NOTICE` here are copied verbatim from the pinned release tag
`v1.10.1` (Apache License 2.0). They are staged into `build/package/licenses/`
by `obs-adapter/CMakeLists.txt` on every build, alongside this plugin's own
Apache-2.0 `LICENSE` (this project's own first-party code was relicensed from
GPL-2.0 to Apache-2.0 to match).

## A correction to the design doc

The design doc's open questions say:

> `client-sdk-cpp`'s bundled `LICENSE.md` (~28 distinct third-party license
> blocks — Google WebRTC, OpenH264, etc.) must ship inside the plugin package

**No such file exists at `v1.10.1`.** Checked, on 2026-09-06:

- The five release archives for this tag (`livekit-sdk-<triple>-1.10.1.tar.gz`
  / `.zip`) contain only `include/`, `lib/`, `bin/` and
  `share/livekit/build-info.json`. No licence file of any kind.
- The repository at tag `v1.10.1` has `LICENSE` (Apache-2.0, 10142 bytes) and
  `NOTICE` (553 bytes) at its root. There is no `LICENSE.md`, no `NOTICE.md`,
  and no `THIRD_PARTY_LICENSES` file.

So what ships here is the Apache-2.0 licence and notice, which is what
actually exists upstream. **The aggregated third-party notice the design doc
expected — covering the WebRTC/OpenH264/etc. code statically linked inside
`liblivekit_ffi.so` — has not been located and is not being shipped.** That
is a real, open licensing question for whoever signs off on distributing
release binaries, not something this packaging step has resolved. Worth
raising upstream, or asking counsel whether the Apache-2.0 NOTICE alone
suffices for a binary redistribution of that library.

## The OpenH264/MPEG-LA royalty question specifically (2026-09-07)

This is narrower and more concrete than the paragraph above, and worth
tracking separately because it changes the actual risk, not just the
paperwork:

Cisco's own OpenH264 FAQ (`https://www.openh264.org/faq.html`) draws a sharp
line: Cisco covers the MPEG-LA/AVC patent-pool royalties **only** for their
own prebuilt OpenH264 binary module, downloaded at install time by the end
user's machine. Anyone who compiles OpenH264 source themselves and
redistributes the result inside their own binary takes on "all applicable
license fees" themselves — Cisco is explicit that it "will not be liable for
any licensing fees incurred by other parties" in that case.

LiveKit's `client-sdk-cpp` links Google's `libwebrtc`, built via the
`webrtc-sdk` org's fork (`github.com/webrtc-sdk/libwebrtc`), whose documented
build args include `rtc_use_h264=true` and `ffmpeg_branding="Chrome"` — the
standard Chromium/WebRTC recipe, in which H.264 encode is provided by a
from-source compile of OpenH264 (pulled from Google's own mirror of the
Cisco source, not downloaded as Cisco's runtime binary) and statically linked
into the resulting `libwebrtc`. That is the exact shape of the case Cisco's
FAQ says voids their royalty coverage.

**This has not been independently confirmed against LiveKit's actual pinned
build** (their `v1.10.1` release archives ship only compiled `lib/`/`bin/`
output, no build manifest showing which GN args actually produced them) —
what's established is that this is `webrtc-sdk/libwebrtc`'s documented
*default* recipe, not a verified fact about LiveKit's specific artifact. But
taking it at face value: `liblivekit_ffi`, which this plugin bundles and
redistributes, likely contains a statically-linked copy of OpenH264 built in
the way that shifts H.264 patent-royalty liability onto whoever redistributes
it — i.e., onto a release of this plugin, not onto Cisco or LiveKit.

This is exactly what C1 (see the main `README.md` `## Status` section) is
tracking, now with a concrete mechanism attached instead of an open question
mark. It does not resolve C1 — if anything it sharpens the case for treating
it as unresolved — and it is not a substitute for an actual legal opinion.