PyAV: add riscv64 build support, use pyav-ffmpeg artifacts in smoke.yml

.github/workflows/smoke.yml

@@ -46,12 +46,19 @@ jobs:
           - {os: ubuntu-24.04, python: "3.14", ffmpeg: "9.0.1", extras: true}
           - {os: ubuntu-24.04, python: "3.12", ffmpeg: "8.1.2"}
           - {os: ubuntu-24.04, python: "3.13", ffmpeg: "9.0.1"}
+          - {os: ubuntu-24.04-riscv, python: "3.14", ffmpeg: "9.0.1"}
           - {os: macos-14, python: "3.12", ffmpeg: "8.1.2"}
           - {os: macos-14, python: "3.14", ffmpeg: "9.0.1"}
 
     env:
       PYAV_PYTHON: python${{ matrix.config.python }}
       PYAV_LIBRARY: ffmpeg-${{ matrix.config.ffmpeg }}
+      # riscv64 wheels (e.g. Pillow) are often missing on PyPI; RISE mirrors
+      # prebuilt wheels for it so uv doesn't have to build them from source.
+      # unsafe-best-match is needed so uv still falls back to PyPI for
+      # packages/versions RISE doesn't happen to carry.
+      UV_INDEX: ${{ matrix.config.os == 'ubuntu-24.04-riscv' && 'https://pypi.riseproject.dev/simple/' || '' }}
+      UV_INDEX_STRATEGY: ${{ matrix.config.os == 'ubuntu-24.04-riscv' && 'unsafe-best-match' || 'first-index' }}
 
     steps:
     - uses: actions/checkout@v7
@@ -66,9 +73,9 @@ jobs:
     - name: OS Packages
       run: |
         case ${{ matrix.config.os }} in
-          ubuntu-24.04)
+          ubuntu-24.04|ubuntu-24.04-riscv)
             sudo apt-get update
-            sudo apt-get install \
+            sudo apt-get install -y \
               autoconf \
               automake \
               build-essential \
@@ -79,7 +86,7 @@ jobs:
               pkg-config \
               zlib1g-dev
             if [[ "${{ matrix.config.extras }}" ]]; then
-              sudo apt-get install doxygen
+              sudo apt-get install -y doxygen
             fi
             ;;
           macos-14)

.github/workflows/tests.yml

@@ -33,6 +33,8 @@ jobs:
             arch: arm64
           - os: macos-15-intel
             arch: x86_64
+          - os: ubuntu-24.04-riscv
+            arch: riscv64
           - os: ubuntu-24.04-arm
             arch: aarch64
           - os: ubuntu-24.04
@@ -61,7 +63,10 @@ jobs:
           CIBW_BEFORE_BUILD: python scripts/fetch-vendor.py --config-file scripts/ffmpeg-latest.json /tmp/vendor
           CIBW_BEFORE_BUILD_MACOS: python scripts/fetch-vendor.py --config-file scripts/ffmpeg-latest.json /tmp/vendor
           CIBW_BEFORE_BUILD_WINDOWS: python scripts\fetch-vendor.py --config-file scripts\ffmpeg-latest.json C:\cibw\vendor
-          CIBW_ENVIRONMENT_LINUX: LD_LIBRARY_PATH=/tmp/vendor/lib:$LD_LIBRARY_PATH PKG_CONFIG_PATH=/tmp/vendor/lib/pkgconfig
+          # riscv64 wheels (e.g. numpy, for CIBW_TEST_REQUIRES) are often missing on
+          # PyPI; RISE mirrors prebuilt wheels for it. unsafe-best-match is needed so
+          # uv still falls back to PyPI for packages/versions RISE doesn't carry.
+          CIBW_ENVIRONMENT_LINUX: LD_LIBRARY_PATH=/tmp/vendor/lib:$LD_LIBRARY_PATH PKG_CONFIG_PATH=/tmp/vendor/lib/pkgconfig${{ matrix.arch == 'riscv64' && ' UV_INDEX=https://pypi.riseproject.dev/simple/ UV_INDEX_STRATEGY=unsafe-best-match' || '' }}
           CIBW_ENVIRONMENT_MACOS: PKG_CONFIG_PATH=/tmp/vendor/lib/pkgconfig LDFLAGS=-headerpad_max_install_names
           CIBW_ENVIRONMENT_WINDOWS: INCLUDE=C:\\cibw\\vendor\\include LIB=C:\\cibw\\vendor\\lib PYAV_SKIP_TESTS=unicode_filename
           CIBW_REPAIR_WHEEL_COMMAND_WINDOWS: delvewheel repair --add-path C:\cibw\vendor\bin -w {dest_dir} {wheel}

scripts/build-deps

@@ -39,6 +39,20 @@ else
     echo "         Building without NVIDIA NVENC/NVDEC support"
 fi
 
+# Some riscv64 toolchains include the Zbb extension by default. FFmpeg's runtime
+# CPU feature checks then get compiled away, causing SIGILL on hardware (like
+# the RISE RISC-V Runners) that doesn't actually implement Zbb
+# (https://trac.ffmpeg.org/ticket/11251). Being explicit about -march=riscv64gc
+# isn't enough to work around this, so also disable FFmpeg's riscv-specific
+# (scalar Zbb + vector) code paths. rv_zicbop's configure dependency is only on
+# "riscv", not "rv", so we have to disable all of the related vector options.
+# This is a temporary fix that should be removed once RISC-V Runners support
+# RVA23.
+CONFFLAGS_RISCV=""
+if [[ "$(uname -m)" == "riscv64" ]]; then
+    CONFFLAGS_RISCV="--extra-cflags=-march=rv64gc --disable-rv --disable-rvv --disable-rv_zicbop --disable-rv_zvbb"
+fi
+
 cd "$PYAV_LIBRARY_ROOT"
 
 # Download and expand the source.
@@ -72,6 +86,7 @@ echo ./configure
     --enable-filter=abuffer,abuffersink,aformat,aresample,atempo,buffer,buffersink,bwdif,color,ebur128,loudnorm,lutrgb,overlay,palettegen,scale,testsrc,vflip,volume \
     --disable-avx512 \
     $CONFFLAGS_NVIDIA \
+    $CONFFLAGS_RISCV \
     --prefix="$PYAV_LIBRARY_PREFIX" \
     || exit 2
 echo