From 5457e99bb78e16151f3f7e2bc41fd31a5bac7f12 Mon Sep 17 00:00:00 2001
From: Adeeb Shihadeh <adeebshihadeh@gmail.com>
Date: Sun, 22 Mar 2026 14:28:34 -0700
Subject: [PATCH] ffmpeg: add hardware-accelerated video decoders (#62)

---
 ffmpeg/build.sh | 98 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 96 insertions(+), 2 deletions(-)

diff --git a/ffmpeg/build.sh b/ffmpeg/build.sh
index 9bc11da..41ac0d4 100755
--- a/ffmpeg/build.sh
+++ b/ffmpeg/build.sh
@@ -4,9 +4,12 @@ set -e
 DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null && pwd)"
 cd "$DIR"
 
+PLATFORM="$(uname -s)"
 FFMPEG_VERSION="7.1"
 ZLIB_VERSION="da607da739fa6047df13e66a2af6b8bec7c2a498"  # v1.3.2
 X264_BRANCH="stable"
+LIBDRM_VERSION="libdrm-2.4.124"
+LIBVA_VERSION="2.22.0"
 INSTALL_DIR="$DIR/ffmpeg/install"
 
 NJOBS="$(nproc 2>/dev/null || sysctl -n hw.ncpu 2>/dev/null || echo 2)"
@@ -48,6 +51,59 @@ make -j"$NJOBS"
 make install
 cd "$DIR"
 
+# --- Build nv-codec-headers (Linux only, for CUDA/NVDEC) ---
+if [ "$PLATFORM" = "Linux" ]; then
+  if [ ! -d "nv-codec-headers-src/.git" ]; then
+    rm -rf nv-codec-headers-src
+    git clone --depth 1 https://git.videolan.org/git/ffmpeg/nv-codec-headers.git nv-codec-headers-src
+  fi
+  make -C nv-codec-headers-src PREFIX="$PREFIX" install
+fi
+
+# --- Build Vulkan-Headers from source (Linux only, need >= 1.3.277 for FFmpeg 7.1) ---
+if [ "$PLATFORM" = "Linux" ]; then
+  if [ ! -d "vulkan-headers-src/.git" ]; then
+    rm -rf vulkan-headers-src
+    git clone --depth 1 https://github.com/KhronosGroup/Vulkan-Headers.git vulkan-headers-src
+  fi
+  cmake -S vulkan-headers-src -B vulkan-headers-src/build -DCMAKE_INSTALL_PREFIX="$PREFIX" >/dev/null
+  cmake --install vulkan-headers-src/build >/dev/null
+fi
+
+# --- Build libdrm + libva statically (Linux only, for VAAPI without runtime deps) ---
+if [ "$PLATFORM" = "Linux" ]; then
+  if ! command -v meson &>/dev/null; then
+    pip3 install --quiet meson ninja 2>/dev/null || python3 -m pip install --quiet meson ninja 2>/dev/null || true
+    command -v meson &>/dev/null || { echo "error: meson is required (apt install meson or pip install meson)" >&2; exit 1; }
+  fi
+
+  if [ ! -d "libdrm-src/.git" ]; then
+    rm -rf libdrm-src
+    git clone --depth 1 --branch "$LIBDRM_VERSION" https://gitlab.freedesktop.org/mesa/drm.git libdrm-src
+  fi
+  rm -rf libdrm-src/builddir
+  meson setup libdrm-src/builddir libdrm-src \
+    --prefix="$PREFIX" --libdir=lib --default-library=static \
+    -Dintel=disabled -Dradeon=disabled -Damdgpu=disabled -Dnouveau=disabled \
+    -Dvmwgfx=disabled -Dtests=false -Dman-pages=disabled -Dcairo-tests=disabled \
+    -Dvalgrind=disabled
+  ninja -C libdrm-src/builddir install
+
+  if [ ! -d "libva-src/.git" ]; then
+    rm -rf libva-src
+    git clone --depth 1 --branch "$LIBVA_VERSION" https://github.com/intel/libva.git libva-src
+  fi
+  rm -rf libva-src/builddir
+  # libva hardcodes shared_library(); patch to library() so --default-library=static works
+  sed -i 's/shared_library(/library(/g' libva-src/va/meson.build
+  PKG_CONFIG_PATH="$PREFIX/lib/pkgconfig${PKG_CONFIG_PATH:+:$PKG_CONFIG_PATH}" \
+  meson setup libva-src/builddir libva-src \
+    --prefix="$PREFIX" --libdir=lib --default-library=static \
+    -Ddisable_drm=false -Dwith_x11=no -Dwith_glx=no -Dwith_wayland=no \
+    -Dwith_win32=no -Denable_docs=false
+  ninja -C libva-src/builddir install
+fi
+
 # --- Build FFmpeg ---
 if [ ! -d "ffmpeg-src/.git" ]; then
   rm -rf ffmpeg-src
@@ -57,6 +113,39 @@ git -C ffmpeg-src fetch --depth 1 origin "n${FFMPEG_VERSION}"
 git -C ffmpeg-src checkout --force FETCH_HEAD
 
 cd ffmpeg-src
+
+# Platform-specific hardware acceleration flags
+HW_FLAGS=()
+if [ "$PLATFORM" = "Linux" ]; then
+  HW_FLAGS+=(
+    # NVIDIA CUDA/NVDEC (uses dlopen at runtime)
+    --enable-ffnvcodec --enable-cuda --enable-cuvid --enable-nvdec
+    --enable-hwaccel=h264_nvdec,hevc_nvdec
+    --enable-decoder=h264_cuvid,hevc_cuvid
+
+    # VAAPI (Intel/AMD — libva linked statically, driver loaded via dlopen at runtime)
+    --enable-vaapi
+    --enable-hwaccel=h264_vaapi,hevc_vaapi
+
+    # V4L2 Memory-to-Memory (embedded: RPi, Qualcomm, Rockchip)
+    --enable-v4l2-m2m
+    --enable-decoder=h264_v4l2m2m,hevc_v4l2m2m
+    --enable-encoder=h264_v4l2m2m,hevc_v4l2m2m
+
+    # Vulkan video decode/encode (uses dlopen at runtime)
+    --enable-vulkan
+    --enable-hwaccel=h264_vulkan,hevc_vulkan
+    --enable-encoder=h264_vulkan,hevc_vulkan
+  )
+elif [ "$PLATFORM" = "Darwin" ]; then
+  HW_FLAGS+=(
+    # VideoToolbox (Apple Silicon / macOS)
+    --enable-videotoolbox
+    --enable-hwaccel=h264_videotoolbox,hevc_videotoolbox
+    --enable-encoder=h264_videotoolbox,hevc_videotoolbox
+  )
+fi
+
 PKG_CONFIG_PATH="$PREFIX/lib/pkgconfig${PKG_CONFIG_PATH:+:$PKG_CONFIG_PATH}" \
 ./configure \
   --cc="${CC:-cc}" \
@@ -80,7 +169,8 @@ PKG_CONFIG_PATH="$PREFIX/lib/pkgconfig${PKG_CONFIG_PATH:+:$PKG_CONFIG_PATH}" \
   --enable-filter=blend,vflip,format,scale,aformat,anull,aresample,null \
   --enable-bsf=extract_extradata,h264_mp4toannexb,hevc_mp4toannexb \
   --extra-cflags="-I$PREFIX/include" \
-  --extra-ldflags="-L$PREFIX/lib"
+  --extra-ldflags="-L$PREFIX/lib" \
+  "${HW_FLAGS[@]}"
 make -j"$NJOBS"
 make install
 cd "$DIR"
@@ -94,7 +184,11 @@ cp "$PREFIX/bin/ffmpeg" "$INSTALL_DIR/bin/"
 cp "$PREFIX/bin/ffprobe" "$INSTALL_DIR/bin/"
 
 # Libraries
-for lib in libavformat.a libavcodec.a libavutil.a libswresample.a libx264.a libz.a; do
+LIBS="libavformat.a libavcodec.a libavutil.a libswresample.a libx264.a libz.a"
+if [ "$PLATFORM" = "Linux" ]; then
+  LIBS="$LIBS libva.a libva-drm.a libdrm.a"
+fi
+for lib in $LIBS; do
   cp "$PREFIX/lib/$lib" "$INSTALL_DIR/lib/"
 done