zemer-cast

Prebuilt FCast sender-SDK native libraries for Zemer's on-demand cast download.

Zemer does not bundle the ~5.3 MB libfcast_sender_sdk.so in its APK. When a user enables casting in settings, the app downloads the matching-ABI library from this repo's GitHub releases, verifies a pinned SHA-256, saves it to app-private storage, and System.load()s it before initialising the cast SDK. Users who never cast never pay the download.

How the libs are produced

.github/workflows/build-release.yml runs entirely in CI:

1. Downloads the official SDK aar from jitpack — org.futo.gitlab.videostreaming.fcast-sdk-jitpack:sender-sdk-minimal:<version> — the exact artifact the app would otherwise bundle.
2. Extracts jni/<abi>/libfcast_sender_sdk.so for the two ABIs Zemer ships: arm64-v8a, armeabi-v7a.
3. Computes SHA-256 for each and publishes a release tagged sdk-<version> with the libs plus a SHA256SUMS file.

Nothing is hand-uploaded — every asset is reproducible by re-running the workflow against the same SDK version, and the SHA256SUMS in each release are what the app pins. That pinned checksum (verified before the library is loaded as native code) is the trust anchor: a tampered download fails the check and is rejected.

Cutting a release

• Manual: Actions → build-release → Run workflow → enter the SDK version (default 0.4.0).
• By tag: push a tag sdk-<version> (e.g. sdk-0.4.0).

Releases

Tag	SDK version	ABIs
sdk-0.4.0	0.4.0	arm64-v8a, armeabi-v7a