From cc8d7a1ec64fe6096a4a5a2f2e159209f9aeefa5 Mon Sep 17 00:00:00 2001
From: Bart <mormegil6@gmail.com>
Date: Sat, 25 Jul 2026 09:14:16 +0200
Subject: [PATCH] Allow building without --enable-nonfree for a redistributable
 image

The flag gates GPL-incompatible external libraries, but this build links
none: the only codec libraries in the configure line are libx264 (GPL),
libopus (BSD) and libvpx (BSD). Its sole effect is marking the resulting
ffmpeg non-redistributable, which blocks publishing a pre-built Earshot
image to a public registry.

ARG ENABLE_NONFREE=1 keeps the default build byte-for-byte identical;
--build-arg ENABLE_NONFREE=0 drops the flag for a redistributable build.
Verified with ENABLE_NONFREE=0: 16-channel Opus (hexadecagonal, no
downmix) and VP9 output unchanged.
---
 Dockerfile | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Dockerfile b/Dockerfile
index a343f1c..2ecac3c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -76,12 +76,17 @@ RUN cd /tmp/ && \
   wget https://github.com/EnvelopSound/ffmpeg/archive/${FFMPEG_VERSION}.tar.gz && \
   tar zxf ${FFMPEG_VERSION}.tar.gz && rm ${FFMPEG_VERSION}.tar.gz
 
+# --enable-nonfree gates GPL-incompatible libraries (e.g. libfdk_aac); this
+# build links none of them, so the flag is a no-op that only marks the binary
+# non-redistributable. Default on (behaviour unchanged); build with
+# --build-arg ENABLE_NONFREE=0 for a redistributable image.
+ARG ENABLE_NONFREE=1
 # Compile ffmpeg.
 RUN cd /tmp/FFmpeg-${FFMPEG_VERSION} && \
    ./configure \
    --enable-version3 \
    --enable-gpl \
-   --enable-nonfree \
+   $( [ "${ENABLE_NONFREE}" = "1" ] && printf '%s' '--enable-nonfree' ) \
    --enable-small \
    --enable-libx264 \
    --enable-libopus \