ffmpeg-wasm-p3-build-v1.sh

#!/bin/bash -x

# verify Emscripten version
emcc -v

# configure FFMpeg with Emscripten
CFLAGS="-s USE_PTHREADS -O3"
LDFLAGS="$CFLAGS -s INITIAL_MEMORY=33554432" # 33554432 bytes = 32 MB
CONFIG_ARGS=(
  --target-os=none        # use none to prevent any os specific configurations
  --arch=x86_32           # use x86_32 to achieve minimal architectural optimization
  --enable-cross-compile  # enable cross compile
  --disable-x86asm        # disable x86 asm
  --disable-inline-asm    # disable inline asm
  --disable-stripping     # disable stripping
  --disable-programs      # disable programs build (incl. ffplay, ffprobe & ffmpeg)
  --disable-doc           # disable doc
  --extra-cflags="$CFLAGS"
  --extra-cxxflags="$CFLAGS"
  --extra-ldflags="$LDFLAGS"
  --nm="llvm-nm -g"
  --ar=emar
  --as=llvm-as
  --ranlib=llvm-ranlib
  --cc=emcc
  --cxx=em++
  --objcc=emcc
  --dep-cc=emcc
)
emconfigure ./configure "${CONFIG_ARGS[@]}"

# build dependencies
emmake make -j4

# build ffmpeg.wasm
mkdir -p wasm/dist
ARGS=(
  -I. -I./fftools
  -Llibavcodec -Llibavdevice -Llibavfilter -Llibavformat -Llibavresample -Llibavutil -Llibpostproc -Llibswscale -Llibswresample
  -Qunused-arguments
  -o wasm/dist/ffmpeg.js fftools/ffmpeg_opt.c fftools/ffmpeg_filter.c fftools/ffmpeg_hw.c fftools/cmdutils.c fftools/ffmpeg.c
  -lavdevice -lavfilter -lavformat -lavcodec -lswresample -lswscale -lavutil -lm
  -O3                                           # Optimize code with performance first
  -s USE_SDL=2                                  # use SDL2
  -s USE_PTHREADS=1                             # enable pthreads support
  -s PROXY_TO_PTHREAD=1                         # detach main() from browser/UI main thread
  -s INVOKE_RUN=0                               # not to run the main() in the beginning
  -s EXPORTED_FUNCTIONS="[_main, _proxy_main]"  # export main and proxy_main funcs
  -s EXTRA_EXPORTED_RUNTIME_METHODS="[FS, cwrap, setValue, writeAsciiToMemory]"   # export preamble funcs
  -s INITIAL_MEMORY=33554432                    # 33554432 bytes = 32 MB
)
emcc "${ARGS[@]}"