Use ffmpeg from jrottenberg/ffmpeg

Eventually would like to move to his 4.0-vaapi image

Dockerfile

@@ -1,15 +1,5 @@
 ARG DOTNET_VERSION=2
 
-
-# Download ffmpeg first to allow quicker rebuild of other layers
-FROM alpine as ffmpeg
-ARG FFMPEG_URL=https://www.johnvansickle.com/ffmpeg/old-releases/ffmpeg-4.0.3-64bit-static.tar.xz
-RUN wget ${FFMPEG_URL} -O - | tar Jxf - \
- && mkdir ffmpeg-bin \
- && mv ffmpeg*/ffmpeg ffmpeg-bin \
- && mv ffmpeg*/ffprobe ffmpeg-bin
-
-
 FROM microsoft/dotnet:${DOTNET_VERSION}-sdk as builder
 WORKDIR /repo
 COPY . .
@@ -20,7 +10,7 @@ RUN export DOTNET_CLI_TELEMETRY_OPTOUT=1 \
     --output /jellyfin \
     Jellyfin.Server
 
-
+FROM jrottenberg/ffmpeg:4.0-scratch as ffmpeg
 FROM microsoft/dotnet:${DOTNET_VERSION}-runtime
 # libfontconfig1 is required for Skia
 RUN apt-get update \
@@ -29,8 +19,8 @@ RUN apt-get update \
  && apt-get clean autoclean \
  && apt-get autoremove \
  && rm -rf /var/lib/{apt,dpkg,cache,log}
+COPY --from=ffmpeg / /
 COPY --from=builder /jellyfin /jellyfin
-COPY --from=ffmpeg /ffmpeg-bin/* /usr/bin/
 EXPOSE 8096
 VOLUME /config /media
 ENTRYPOINT dotnet /jellyfin/jellyfin.dll -programdata /config