Synology Docker Batch convert E AC3 to AC3

Synology Video Station does not support the E-AC3 codec (due to licencing limitations). The ffmpeg docker can be used to work around this situation. In order to do hardware accelerated batch conversions you can create the following script, which you can run in the applicable video directory.

#!/bin/sh

for f in *.mkv; do docker run --rm --device /dev/dri:/dev/dri -v "$(pwd):$(pwd)" -w "$(pwd)" jrottenberg/ffmpeg:vaapi -y -i "$f" -map 0 -c:v copy -c:a ac3 -b:a 640k -c:s copy "${f%.*}-ac; done