Automated Blu-ray ISO to MKV Conversion on Synology NAS using Docker + MakeMKV

[Cotignac 3]

Hi everyone,

I wanted to share a setup I've built for automatically converting Blu-ray ISO files to MKV on my Synology NAS. It might be useful for others running Emby on NAS hardware.

What it does

The script iso_convert.sh converts Blu-ray ISO files to MKV using MakeMKV and MKVToolNix, running inside a Docker container on Synology DSM 7. It uses a simple queue-based folder structure — you drop a movie folder with an ISO file into a queue directory, start the container in Portainer, and it handles the rest.

The script automatically selects the correct title from the ISO based on duration and file size, converts it to MKV, and places the result in a done folder ready for Emby to pick up. If something goes wrong, the file ends up in a failed folder with a log, and an email notification is sent either way.

The folder workflow

• /volume1/iso/queue/ — drop your movie folder + ISO here
• /volume1/iso/done/ — converted MKV lands here
• /volume1/iso/failed/ — failed conversions with log
• /volume1/iso/manual/ — for anything needing manual attention

Tech stack

• Synology NAS with DSM 7
• Docker + Portainer for container management
• MakeMKV 1.18.3 (compiled from source inside the container)
• MKVToolNix for post-processing
• msmtp for email notifications
• The container runs once per job and exits (restart: no), keeping resource usage minimal

A few notes

The Docker image is built locally on the NAS since it compiles MakeMKV from source — the build takes about 10–15 minutes but only needs to be done once (or when MakeMKV updates). The MakeMKV beta key is passed as an environment variable in Portainer, so updating the monthly key is just a quick edit without touching the image.

This fits nicely into a broader media pipeline alongside Radarr, Sonarr, and qBittorrent — ISOs get converted to MKV and land directly where Emby can import them.

Disclaimer

If anyone wants to use this script, please be aware that you do so entirely at your own risk. I take no responsibility for any errors, data loss, or unintended consequences that the script may cause. That said, I strongly recommend always copying your ISO file into the /queue directory rather than moving it — that way your original file is safe if anything goes wrong during conversion.

Happy to answer questions if anyone wants to set something similar up.