Cross-compile FFmpeg for rockchip ARM platform using LLVM toolchain on macOS

build_ffmpeg_rockchip.sh

export ARCH=armv7
export CPU=armv7-a
export OS=linux
export TARGET=armv7-linux-gnueabihf
export SYSROOT=../sysroot

export PREFIX=/usr
export TOOLCHAIN=/usr/local/opt/llvm/bin
export CC=$TOOLCHAIN/clang
export CXX=$TOOLCHAIN/clang++
export LD=$TOOLCHAIN/clang
export NM=$TOOLCHAIN/llvm-nm
export AS=$TOOLCHAIN/llvm-as
export AR=$TOOLCHAIN/llvm-ar
export RANLIB=$TOOLCHAIN/llvm-ranlib
export STRIP=$TOOLCHAIN/llvm-strip

export PKG_CONFIG=$(which pkg-config)
export PKG_CONFIG_LIBDIR=$SYSROOT/usr/lib/arm-linux-gnueabihf/pkgconfig
export PKG_CONFIG_SYSROOT_DIR=$SYSROOT

export TARGET_BUILD_DIR=$SYSROOT/home/firefly/ffmpeg

./configure \
--enable-cross-compile --prefix=$PREFIX --cross-prefix=$TOOLCHAIN \
--cc=$CC --cxx=$CXX --ld=$LD --nm=$NM --strip=$STRIP --ranlib=$RANLIB \
--arch=$ARCH --cpu=$CPU --target-os=$OS --sysroot=$SYSROOT \
--extra-cflags="--target=$TARGET -march=$CPU" \
--extra-ldflags="--target=$TARGET -march=$CPU -fuse-ld=lld" \
--pkg-config=$PKG_CONFIG --target-path=$TARGET_BUILD_DIR \
--disable-static --enable-shared --enable-pic --enable-hardcoded-tables \
--enable-gpl --enable-nonfree --enable-version3 \
--disable-armv5te --disable-armv6 --disable-armv6t2 \
--enable-rkmpp --enable-libdrm \
--disable-doc --disable-htmlpages --disable-txtpages --disable-manpages --disable-podpages \
--disable-encoders --enable-encoder=rawvideo --enable-encoder=wrapped_avframe \
--disable-muxers --enable-muxer=null --enable-muxer=rtp --enable-muxer=rtsp --enable-demuxer=rawvideo --enable-muxer=mov --enable-muxer=mp4 \
--disable-decoders --enable-decoder=aac --enable-decoder=aac_latm --enable-decoder=h264_rkmpp --enable-decoder=hevc_rkmpp --enable-decoder=vp9_rkmpp \
--disable-filters --enable-filter=anull --enable-filter=null --enable-filter=aresample --enable-filter=pad --enable-filter=scale --enable-filter=overlay --enable-filter=amix --enable-filter=aresample \
--disable-demuxers --enable-demuxer=sdp --enable-demuxer=matroska --enable-demuxer=rtp --enable-demuxer=rtsp --enable-demuxer=h264 --enable-demuxer=hevc --enable-demuxer=rawvideo --enable-demuxer=mpc --enable-demuxer=mov \
--disable-parsers --enable-parser=mpeg4video --enable-parser=aac --enable-parser=h264 --enable-parser=hevc --enable-parser=vp9 \
--disable-protocols --enable-protocol=file --enable-protocol=unix --enable-protocol=tcp --enable-protocol=udp --enable-protocol=udplite --enable-protocol=rtp --enable-protocol=async \
--disable-bsfs --enable-bsf=null --enable-bsf=aac_adtstoasc --enable-bsf=h264_metadata --enable-bsf=h264_mp4toannexb --enable-bsf=hevc_metadata --enable-bsf=hevc_mp4toannexb --enable-bsf=vp9_metadata \
--disable-indevs --enable-indev=v4l2 \
--disable-outdevs --enable-outdev=v4l2 --enable-outdev=fbdev \
--disable-hwaccels \

Prerequisites:

1. LLVM toolchain installed in /usr/local/opt/llvm/on the host
2. SYSROOT set to the root of the target system (I used sshfs to mount it remotely to a local dir on the host)
3. libdrm and rockchip_mpp libs are installed on the target system (with valid pkg-config files in /usr/lib/pkg-config)

A cautionary tale about sshfs: You NEED to specify -o follow_symlinks,transform_symlinks when mounting the remote target rootfs to a SYSROOT directory on the host. For Debian-based systems, some system shared libraries are symlinked to absolute paths, for instance /usr/lib/$arch/libm.so -> /lib/$arch/libm.so.6, which causes big problem for cross-compilation since the compiler cannot locate those libraries (their symlinks are now pointing to the absolute paths on the host OS). If the compiler cannot find the shared libraries, it would try to use their static counterparts and causes subtle link errors. Make sure to specify the sshfs options to map those absolute paths symlinks to relative paths.

Does this enable hardware Encoding, Decoding or both for ffmpeg on rockchip arm?

Does this enable hardware Encoding, Decoding or both for ffmpeg on rockchip arm?

Unfortunately, HW encoding is not supported. You may need to use mpp APIs directly.