Update Dockerfile

Author: jeromewu

Dockerfile

@@ -20,14 +20,6 @@ ENV FFMPEG_MT=$FFMPEG_MT
 RUN apt-get update && \
       apt-get install -y pkg-config autoconf automake libtool ragel
 
-# Build zimg
-FROM emsdk-base AS zimg-builder
-ENV ZIMG_BRANCH=release-3.0.5
-RUN apt-get update && apt-get install -y git
-RUN git clone --recursive -b $ZIMG_BRANCH https://github.com/sekrit-twc/zimg.git /src
-COPY build/zimg.sh /src/build.sh
-RUN bash -x /src/build.sh
-
 # Build x264
 FROM emsdk-base AS x264-builder
 ENV X264_BRANCH=4-cores
@@ -132,6 +124,14 @@ ADD https://github.com/libass/libass.git#$LIBASS_BRANCH /src
 COPY build/libass.sh /src/build.sh
 RUN bash -x /src/build.sh
 
+# Build zimg
+FROM emsdk-base AS zimg-builder
+ENV ZIMG_BRANCH=release-3.0.5
+RUN apt-get update && apt-get install -y git
+RUN git clone --recursive -b $ZIMG_BRANCH https://github.com/sekrit-twc/zimg.git /src
+COPY build/zimg.sh /src/build.sh
+RUN bash -x /src/build.sh
+
 # Base ffmpeg image with dependencies and source code populated.
 FROM emsdk-base AS ffmpeg-base
 RUN embuilder build sdl2 sdl2-mt
@@ -147,7 +147,7 @@ COPY --from=libwebp-builder $INSTALL_DIR $INSTALL_DIR
 COPY --from=libass-builder $INSTALL_DIR $INSTALL_DIR
 COPY --from=zimg-builder $INSTALL_DIR $INSTALL_DIR
 
-# Build ffmpeg with --enable-libzimg
+# Build ffmpeg
 FROM ffmpeg-base AS ffmpeg-builder
 COPY build/ffmpeg.sh /src/build.sh
 RUN bash -x /src/build.sh \