JavaH264 (nexbit fork)

Java bindings for the OpenH264 library written in Rust using JNI.

This is a fork of DimasKama/JavaH264 (MIT), maintained for use in BitCam. Original work © DimasKama; modifications © Zakhar Stupak. See LICENSE (MIT + the bundled Cisco OpenH264 BSD notice).

Changes from upstream

• Package renamed to dev.nexbit.javah264 (JNI symbols updated accordingly).
• Thread safety: H264Decoder/H264Encoder guard the native pointer with a ReadWriteLock, so close() can no longer free the native instance while a decode/encode is in flight on another thread (this was a use-after-free that could crash the JVM).
• Panic safety: every unwrap()/expect() on the JNI boundary now throws a Java exception instead of panicking — under panic = "abort" a panic would take down the whole JVM.
• Zero-copy decode: H264Decoder.decodeRGBAInto(byte[], ByteBuffer) writes the decoded pixels straight into a caller-provided direct ByteBuffer, avoiding a fresh Java array allocation per frame.
• Published under dev.nexbit:javah264 (see below).

Usage

In your build.gradle:

repositories {
    maven {
        name = "JavaH264 (GitHub Packages)"
        url = "https://maven.pkg.github.com/NexBitstd/JavaH264"
        credentials {
            username = System.getenv("GITHUB_ACTOR")
            password = System.getenv("GITHUB_TOKEN") // PAT with read:packages
        }
    }
}

dependencies {
    implementation "dev.nexbit:javah264:${javah264_version}"
}

Native libraries for all supported platforms are bundled inside the jar and extracted at runtime by LibraryLoader.

Building

The native part is built per-platform by GitHub Actions (.github/workflows/) and the resulting .so/.dylib/.dll are dropped into src/main/resources/natives/<platform>/ before the Gradle build assembles the jar. To build a single native locally:

cd rust && cargo build --release --lib

Credits

• JavaH264 by DimasKama — the project this is forked from
• OpenH264
• openh264-rs
• jni-rs