use ffmpeg 4.0.3 instead of distro provided (fixes chromecast + androidtv)

Dockerfile

@@ -10,9 +10,23 @@ RUN export DOTNET_CLI_TELEMETRY_OPTOUT=1 \
 FROM microsoft/dotnet:${DOTNET_VERSION}-runtime
 COPY --from=builder /jellyfin /jellyfin
 EXPOSE 8096
-RUN apt update \
- && apt install -y ffmpeg
+
+#RUN apt update \
+# && apt install -y ffmpeg
+#Use a ffmpeg 4.0.3 build for now, until we have our own (fixes chromecasts and androidtv app)
+
 VOLUME /config /media
+
+RUN apt update
+RUN apt install -y wget xz-utils
+RUN mkdir /ffmpeg
+WORKDIR /ffmpeg
+RUN wget https://www.johnvansickle.com/ffmpeg/old-releases/ffmpeg-4.0.3-64bit-static.tar.xz
+RUN tar xf /ffmpeg/ffmpeg-4.0.3-64bit-static.tar.xz
+RUN ln -s /ffmpeg/ffmpeg-4.0.3-64bit-static/ffmpeg /usr/local/sbin/ffmpeg
+RUN ln -s /ffmpeg/ffmpeg-4.0.3-64bit-static/ffprobe /usr/local/sbin/ffprobe
+
+
 ENTRYPOINT if [ -n "$PUID$PGUID" ]; \
     then echo "PUID/PGID are deprecated. Use Docker user param." >&2; exit 1; \
     else dotnet /jellyfin/jellyfin.dll -programdata /config; fi