daquino94/flacconverter

This project is a Docker container that watches a folder for FLAC audio files and automatically converts them into M4A (AAC) or MP3 files. It is built for people who keep a lossless music library on disk but also want smaller, more portable copies for devices like an iPod, without converting each new file by hand. When the container starts, it scans the source folder for FLAC files and converts any that do not already have an up to date copy in the output folder. Conversions run in parallel, up to a number of jobs you can set yourself. Every so often, controlled by a POLL_INTERVAL setting, it rescans the folder from scratch so new files, new albums, or new subfolders get picked up without restarting the container. The tool checks folders on a timer rather than watching for live filesystem events, because that kind of live watching is unreliable across Docker on non-Linux hosts, so new files may take up to POLL_INTERVAL seconds to be noticed rather than being converted instantly. The output keeps the same folder structure as the source, for example an Artist and Album layout, and it copies over embedded cover art and metadata tags like title, artist, album, and track number. You can choose whether the output format is M4A or MP3, set the bitrate, and choose whether the original FLAC file gets deleted after conversion. Setup is done through a docker-compose.yml file where you point the container at your source and output folders and set these options as environment variables. For audio quality, the README explains that at the same bitrate AAC generally sounds better than MP3, and that this container uses a specific AAC encoder chosen to avoid artifacts that ffmpeg's default encoder can introduce on some tracks. If a source file has no embedded cover art, no cover gets added automatically. The project is licensed under the MIT License.