ffmpeg wasm + emscript build script

embuild.sh

#!/bin/bash -x

# verify Emscripten version
emcc -v

# 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 fftools/sync_queue.c 
  fftools/ffmpeg_mux.c fftools/ffmpeg_demux.c fftools/opt_common.c
  fftools/objpool.c fftools/thread_queue.c
  -lavdevice -lavfilter -lavformat -lavcodec -lswresample -lswscale -lavutil -lm
  -lnodefs.js
  -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 EXPORTED_FUNCTIONS="[_main, __emscripten_proxy_main]"               # export main func
  -s EXPORTED_RUNTIME_METHODS="[FS, cwrap, setValue, writeAsciiToMemory]"   # export preamble funcs
  -s INITIAL_MEMORY=33554432                    # 33554432 bytes = 32 MB
  -s LLD_REPORT_UNDEFINED
  -s ALLOW_MEMORY_GROWTH=1
  -s EXIT_RUNTIME=1
)
emcc "${ARGS[@]}"

emconfig.sh

#!/bin/bash -x

# verify Emscripten version
emcc -v

# configure FFMpeg with Emscripten
CFLAGS="-s USE_PTHREADS"
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"
  --ar=emar
  --ranlib=emranlib
  --cc=emcc
  --cxx=em++
  --objcc=emcc
  --dep-cc=emcc
)
emconfigure ./configure "${CONFIG_ARGS[@]}"

emmake.sh

#!/bin/bash -x

# verify Emscripten version
emcc -v

# build dependencies
emmake make -j4