diff --git a/.github/workflows/build-binaries.yml b/.github/workflows/build-binaries.yml
new file mode 100644
index 0000000..46b5e5a
--- /dev/null
+++ b/.github/workflows/build-binaries.yml
@@ -0,0 +1,216 @@
+# Builds the FFmpeg binaries for every slice the package ships (issue #7).
+#
+# Each slice builds on its own runner in parallel, then one macOS job merges
+# them with scripts/ffmpeg/package.sh β the same script a local release uses β
+# so a CI build and a local build produce the same bundle layout, checksum
+# manifest, and build-info.txt.
+#
+# Run it by hand from the Actions tab (optionally attaching the result to a
+# GitHub release), or let it run on pull requests that touch the build scripts.
+name: Build binaries
+
+on:
+ workflow_dispatch:
+ inputs:
+ ffmpeg_version:
+ description: FFmpeg release to build
+ default: '9.0.1'
+ release_tag:
+ description: >-
+ Attach the bundle to this GitHub release (for example v0.6.0). Leave
+ empty to only keep it as a workflow artifact.
+ default: ''
+ pull_request:
+ paths:
+ - scripts/ffmpeg/**
+ - .github/workflows/build-binaries.yml
+
+concurrency:
+ group: build-binaries-${{ github.ref }}
+ cancel-in-progress: true
+
+env:
+ FFMPEG_VERSION: ${{ inputs.ffmpeg_version || '9.0.1' }}
+ FFMPEG_WORKSPACE: ${{ github.workspace }}/.build
+ NDK_VERSION: 27.1.12297006
+
+jobs:
+ android:
+ name: Android ${{ matrix.abi }}
+ runs-on: ubuntu-latest
+ timeout-minutes: 120
+ strategy:
+ fail-fast: false
+ matrix:
+ abi: [arm64-v8a, armeabi-v7a, x86_64]
+ steps:
+ - uses: actions/checkout@v4
+
+ # fontconfig 2.16 needs Meson 1.6+, newer than the apt package, so Meson
+ # comes from pip.
+ - name: Install build tools
+ run: |
+ sudo apt-get update
+ sudo apt-get install -y --no-install-recommends \
+ ninja-build nasm yasm pkg-config gperf \
+ autoconf automake libtool cmake xz-utils
+ python3 -m pip install --user 'meson>=1.6'
+ echo "$HOME/.local/bin" >> "$GITHUB_PATH"
+
+ # Pinned to the same NDK the local build uses, so both produce the same
+ # binaries; the runner's preinstalled "latest" NDK moves over time.
+ - name: Install Android NDK ${{ env.NDK_VERSION }}
+ run: |
+ yes | "$ANDROID_HOME/cmdline-tools/latest/bin/sdkmanager" --install "ndk;$NDK_VERSION" > /dev/null
+ echo "ANDROID_NDK=$ANDROID_HOME/ndk/$NDK_VERSION" >> "$GITHUB_ENV"
+
+ - name: Cache dependency sources
+ uses: actions/cache@v4
+ with:
+ path: ${{ env.FFMPEG_WORKSPACE }}/deps/*.tar.*
+ key: deps-${{ hashFiles('scripts/ffmpeg/build-android.sh', 'scripts/ffmpeg/build-ios.sh') }}
+
+ - name: Build FFmpeg for ${{ matrix.abi }}
+ run: |
+ scripts/ffmpeg/fetch-source.sh
+ scripts/ffmpeg/build-android.sh "${{ matrix.abi }}"
+
+ - name: Show what was built
+ run: |
+ lib="$FFMPEG_WORKSPACE/out/android-${{ matrix.abi }}/lib/libmunimffmpeg.so"
+ ls -la "$lib"
+ "$ANDROID_NDK"/toolchains/llvm/prebuilt/linux-x86_64/bin/llvm-readelf -d "$lib" | grep NEEDED
+
+ - name: Upload build logs
+ if: always()
+ uses: actions/upload-artifact@v4
+ with:
+ name: logs-android-${{ matrix.abi }}
+ path: ${{ env.FFMPEG_WORKSPACE }}/build/*.log
+ if-no-files-found: ignore
+
+ - name: Upload slice
+ uses: actions/upload-artifact@v4
+ with:
+ name: slice-android-${{ matrix.abi }}
+ if-no-files-found: error
+ path: |
+ ${{ env.FFMPEG_WORKSPACE }}/out/android-${{ matrix.abi }}/lib/libmunimffmpeg.so
+ ${{ env.FFMPEG_WORKSPACE }}/build/ffmpeg-${{ matrix.abi }}-configure.log
+ ${{ env.FFMPEG_WORKSPACE }}/build/android-${{ matrix.abi }}/ffbuild/config.log
+
+ ios:
+ name: iOS ${{ matrix.sdk }} ${{ matrix.arch }}
+ runs-on: macos-15
+ timeout-minutes: 120
+ strategy:
+ fail-fast: false
+ matrix:
+ include:
+ - { sdk: iphoneos, arch: arm64 }
+ - { sdk: iphonesimulator, arch: arm64 }
+ - { sdk: iphonesimulator, arch: x86_64 }
+ steps:
+ - uses: actions/checkout@v4
+
+ - name: Install build tools
+ run: brew install meson ninja nasm yasm pkg-config gperf autoconf automake libtool
+
+ - name: Cache dependency sources
+ uses: actions/cache@v4
+ with:
+ path: ${{ env.FFMPEG_WORKSPACE }}/deps/*.tar.*
+ key: deps-${{ hashFiles('scripts/ffmpeg/build-android.sh', 'scripts/ffmpeg/build-ios.sh') }}
+
+ - name: Build FFmpeg for ${{ matrix.sdk }} ${{ matrix.arch }}
+ run: |
+ scripts/ffmpeg/fetch-source.sh
+ scripts/ffmpeg/build-ios.sh "${{ matrix.sdk }}" "${{ matrix.arch }}"
+
+ - name: Show what was built
+ run: |
+ lib="$FFMPEG_WORKSPACE/out/ios-${{ matrix.sdk }}-${{ matrix.arch }}/lib/libmunimffmpeg.a"
+ ls -la "$lib"
+ lipo -info "$lib"
+
+ - name: Upload build logs
+ if: always()
+ uses: actions/upload-artifact@v4
+ with:
+ name: logs-ios-${{ matrix.sdk }}-${{ matrix.arch }}
+ path: ${{ env.FFMPEG_WORKSPACE }}/build/*.log
+ if-no-files-found: ignore
+
+ - name: Upload slice
+ uses: actions/upload-artifact@v4
+ with:
+ name: slice-ios-${{ matrix.sdk }}-${{ matrix.arch }}
+ if-no-files-found: error
+ path: |
+ ${{ env.FFMPEG_WORKSPACE }}/out/ios-${{ matrix.sdk }}-${{ matrix.arch }}/lib/libmunimffmpeg.a
+ ${{ env.FFMPEG_WORKSPACE }}/build/ffmpeg-${{ matrix.sdk }}-${{ matrix.arch }}-configure.log
+ ${{ env.FFMPEG_WORKSPACE }}/build/ios-${{ matrix.sdk }}-${{ matrix.arch }}/ffbuild/config.log
+
+ package:
+ name: Package bundle
+ needs: [android, ios]
+ runs-on: macos-15
+ timeout-minutes: 30
+ steps:
+ - uses: actions/checkout@v4
+ - uses: actions/setup-node@v4
+ with:
+ node-version: 22
+
+ # Every slice artifact was uploaded relative to the workspace root, so
+ # merging them recreates the out/ and build/ layout package.sh expects.
+ - name: Collect slices
+ uses: actions/download-artifact@v4
+ with:
+ pattern: slice-*
+ path: ${{ env.FFMPEG_WORKSPACE }}
+ merge-multiple: true
+
+ - name: Assemble the bundle
+ run: scripts/ffmpeg/package.sh
+
+ - name: Summarise
+ run: |
+ {
+ echo '### munim-ffmpeg binaries'
+ echo
+ echo '```'
+ cat scripts/binaries.json
+ echo '```'
+ echo
+ echo 'build-info.txt
'
+ echo
+ echo '```'
+ cat dist-binaries/build-info.txt
+ echo '```'
+ echo '