Reorg folders and use core as ffmpeg from now on

Dockerfile

@@ -1,23 +1,24 @@
+# syntax=docker/dockerfile-upstream:master-labs
+
 # Base emsdk image with environment variables.
 FROM emscripten/emsdk:3.1.18 AS emsdk-base
 ARG EXTRA_CFLAGS
 ARG EXTRA_LDFLAGS
+ARG FFMPEG_ST
 ARG FFMPEG_MT
 ENV INSTALL_DIR=/src/build
 ENV FFMPEG_VERSION=n5.1
+ENV X264_BRANCH=stable-wasm
 ENV CFLAGS="$CFLAGS $EXTRA_CFLAGS"
 ENV LDFLAGS="$LDFLAGS $CFLAGS $EXTRA_LDFLAGS"
 ENV EM_PKG_CONFIG_PATH=$EM_PKG_CONFIG_PATH:$INSTALL_DIR/lib/pkgconfig:/emsdk/upstream/emscripten/system/lib/pkgconfig
 ENV PKG_CONFIG_PATH=$PKG_CONFIG_PATH:$EM_PKG_CONFIG_PATH
+ENV FFMPEG_ST=$FFMPEG_ST
 ENV FFMPEG_MT=$FFMPEG_MT
 
 # Build x264
 FROM emsdk-base AS x264-builder
-RUN git clone \
-      --branch stable \
-      --depth 1 \
-      https://github.com/ffmpegwasm/x264 \
-      /src
+ADD https://github.com/ffmpegwasm/x264.git#$X264_BRANCH /src
 COPY build/x264.sh /src/build.sh
 RUN bash /src/build.sh
 
@@ -25,12 +26,8 @@ RUN bash /src/build.sh
 FROM emsdk-base AS ffmpeg-base
 RUN apt-get update && \
       apt-get install -y pkg-config
-RUN embuilder build sdl2
-RUN git clone \
-      --branch $FFMPEG_VERSION \
-      --depth 1 \
-      https://github.com/FFmpeg/FFmpeg \
-      /src
+RUN embuilder build sdl2 sdl2-mt
+ADD https://github.com/FFmpeg/FFmpeg.git#$FFMPEG_VERSION /src
 COPY --from=x264-builder $INSTALL_DIR $INSTALL_DIR
 
 # Build ffmpeg
@@ -38,15 +35,15 @@ FROM ffmpeg-base AS ffmpeg-builder
 COPY build/ffmpeg.sh /src/build.sh
 RUN bash /src/build.sh
 
-# Build ffmpeg-core.wasm
+# Build ffmpeg.wasm
 FROM ffmpeg-builder AS ffmpeg-wasm-builder
 COPY src/bind /src/wasm/bind
 COPY src/fftools /src/wasm/fftools
 RUN mkdir -p /src/dist
 COPY build/ffmpeg-wasm.sh build.sh
 # FIXME: find a way to export both entry points in one command.
-RUN bash /src/build.sh -o dist/ffmpeg-core.cjs
-RUN bash /src/build.sh -sEXPORT_ES6 -o dist/ffmpeg-core.js
+RUN bash /src/build.sh -o dist/ffmpeg.cjs
+RUN bash /src/build.sh -sEXPORT_ES6 -o dist/ffmpeg.js
 
 # Export ffmpeg-core.wasm to dist/, use `docker buildx build -o . .` to get assets
 FROM scratch AS exportor