Help cross compiling ffmpeg

[epoupon]

Hello!

I don't manage to cross compile ffmpeg on Alpine 3.14 (well I test on amd64 first).
Here is what I try to compile:

RUN \
    DIR=/tmp/ffmpeg && mkdir -p ${DIR} && cd ${DIR} && \
    ./configure \
    --enable-cross-compile \
    --cross-prefix=$(xx-clang --print-target-triple)- \
    --arch=$(xx-info arch) \
    --target-os=$(xx-info os) \
    --prefix=${PREFIX} \
    --disable-autodetect \
    --disable-debug \
    --disable-doc \
    --disable-ffplay \
    --disable-ffprobe \
    --disable-openssl \
    --disable-postproc \
    --disable-pixelutils \
    --disable-network \
    --enable-shared \
    --disable-static \
    --enable-gpl \
    --enable-small \
    --enable-version3 \
    --enable-nonfree \
    --enable-libmp3lame \
    --enable-libopenjpeg \
    --enable-libopus \
    --enable-libvorbis \
    --disable-everything \
    --enable-decoder=aac*,ac3*,alac,als,flac,mp3*,libopus,pcm*,libvorbis,wavpack,wma*,libopenjpg,png \
    --enable-encoder=libmp3lame,libopus,libvorbis \
    --enable-demuxer=aac,aiff,asf,flac,ipod,ogg,matroska,mov,mp3,mp4,wav,wv,webm \
    --enable-muxer=ogg,matroska,mp3,webm \
    --enable-protocol=file,pipe \
    --enable-filter=aresample \
    --extra-libs=-ldl && \
    make && \
    make install && \
    make distclean

But it fails at the end with:

#14 122.1  4003 |             input_streams[i]->st->codec->debug = debug;
#14 122.1       |             ^~~~~~~~~~~~~
#14 122.1 In file included from fftools/ffmpeg.c:43:
#14 122.1 ./libavformat/avformat.h:878:21: note: declared here
#14 122.1   878 |     AVCodecContext *codec;
#14 122.1       |                     ^~~~~
#14 123.9 LD    ffmpeg_g
#14 123.9 STRIP ffmpeg
#14 123.9 /bin/sh: x86_64-alpine-linux-musl-strip: not found
#14 123.9 make: *** [Makefile:101: ffmpeg] Error 127

What do you think?

[tonistiigi]

/bin/sh: x86_64-alpine-linux-musl-strip: not found

For strip binary you need to install apk add llvm (not xx-apk).

If this is not it then post the full Dockerfile and command you are running so other people can reproduce.

[epoupon]

Thanks for your answer!
It seems to work when not cross compiling but it fails hard when trying to build for linux/arm64:

#18 [build  7/13] RUN   DIR=/tmp/ffmpeg && mkdir -p ${DIR} && cd ${DIR} &&      PKG_CONFIG_PATH=/$(xx-info)/usr/lib/pkgconfig ./configure       --enable-cross-compile  --cross-prefix=$(xx-clang --print-target-triple)-       --arch=$(xx-info arch)  --target-os=$(xx-info os)       --prefix=/tmp/install   --disable-autodetect    --disable-debug         --disable-doc      --disable-ffplay        --disable-ffprobe       --disable-openssl       --disable-postproc      --disable-pixelutils    --disable-network       --enable-shared         --disable-static        --enable-gpl    --enable-small  --enable-version3       --enable-nonfree        --enable-libmp3lame     --enable-libopenjpeg    --enable-libopus        --enable-libvorbis         --disable-everything    --enable-decoder=aac*,ac3*,alac,als,flac,mp3*,libopus,pcm*,libvorbis,wavpack,wma*,libopenjpg,png        --enable-encoder=libmp3lame,libopus,libvorbis   --enable-demuxer=aac,aiff,asf,flac,ipod,ogg,matroska,mov,mp3,mp4,wav,wv,webm    --enable-muxer=ogg,matroska,mp3,webm    --enable-protocol=file,pipe     --enable-filter=aresample  --extra-libs=-ldl &&    make &&         make install &&         make distclean
#18 sha256:a7f1c3eab9b55110c6e7ccf330d1721af6565462673a5c7370045072a0dafa17
#18 0.920 aarch64-alpine-linux-musl-gcc is unable to create an executable file.
#18 0.920 C compiler test failed.
#18 0.921
#18 0.921 If you think configure made a mistake, make sure you are using the latest
#18 0.921 version from Git.  If the latest version fails, report the problem to the
#18 0.921 [email protected] mailing list or IRC #ffmpeg on irc.freenode.net.
#18 0.922 Include the log file "ffbuild/config.log" produced by configure as this will help
#18 0.922 solve the problem.

Here is my current Dockerfile:

FROM --platform=$BUILDPLATFORM tonistiigi/xx AS xx
FROM --platform=$BUILDPLATFORM alpine:3.14 AS build

ARG BUILD_PACKAGES=" \
    clang \
    make \
    cmake \
    autoconf \
    automake \
    binutils \
    coreutils \
    libtool \
    lld \
    llvm \
    curl \
    nasm \
    yasm \
    pkgconfig"

RUN apk add --no-cache ${BUILD_PACKAGES}

ARG LMS_BUILD_PACKAGES=" \
    gcc \
    g++ \
    musl-dev \
    boost-dev \
    libconfig-dev \
    taglib-dev \
    openjpeg-dev \
    libpng-dev \
    libogg-dev \
    opus-dev \
    libvorbis-dev \
    lame-dev \
    zlib-dev \
    openssl-dev \
    gtest-dev"

COPY --from=xx / /

ARG TARGETPLATFORM
RUN xx-apk add --no-scripts --no-cache ${LMS_BUILD_PACKAGES}

ARG PREFIX="/tmp/install"

# ffmpeg
ARG FFMPEG_VERSION=4.1.4
RUN  \
    DIR=/tmp/ffmpeg && mkdir -p ${DIR} && cd ${DIR} && \
    curl -sLO https://ffmpeg.org/releases/ffmpeg-${FFMPEG_VERSION}.tar.bz2 && \
    tar -jx --strip-components=1 -f ffmpeg-${FFMPEG_VERSION}.tar.bz2

RUN \
    DIR=/tmp/ffmpeg && mkdir -p ${DIR} && cd ${DIR} && \
    PKG_CONFIG_PATH=/$(xx-info)/usr/lib/pkgconfig ./configure \
    --enable-cross-compile \
    --cross-prefix=$(xx-clang --print-target-triple)- \
    --arch=$(xx-info arch) \
    --target-os=$(xx-info os) \
    --prefix=${PREFIX} \
    --disable-autodetect \
    --disable-debug \
    --disable-doc \
    --disable-ffplay \
    --disable-ffprobe \
    --disable-openssl \
    --disable-postproc \
    --disable-pixelutils \
    --disable-network \
    --enable-shared \
    --disable-static \
    --enable-gpl \
    --enable-small \
    --enable-version3 \
    --enable-nonfree \
    --enable-libmp3lame \
    --enable-libopenjpeg \
    --enable-libopus \
    --enable-libvorbis \
    --disable-everything \
    --enable-decoder=aac*,ac3*,alac,als,flac,mp3*,libopus,pcm*,libvorbis,wavpack,wma*,libopenjpg,png \
    --enable-encoder=libmp3lame,libopus,libvorbis \
    --enable-demuxer=aac,aiff,asf,flac,ipod,ogg,matroska,mov,mp3,mp4,wav,wv,webm \
    --enable-muxer=ogg,matroska,mp3,webm \
    --enable-protocol=file,pipe \
    --enable-filter=aresample \
    --extra-libs=-ldl && \
    make && \
    make install && \
    make distclean

[tonistiigi]

--cc=xx-clang seems to be enough.

ffmpeg seems to be using hand-written configure so you need to study the flags and pass manually like it expects them. I've not verified the rest of the options.

#18 0.920 aarch64-alpine-linux-musl-gcc is unable to create an executable file.

xx does not support gcc on alpine(unless set up manually) because gcc requires separate compiler packages for each target architecture that alpine does not ship.