sync_music - Sync music library to external devices

This program allows you to synchronize your music library for the usage on primitive music players that don't support the diversity of your collection.

In normal operation mode, sync_music performs its synchronization tasks depending on the input file format. Music files in FLAC, Ogg Vorbis and M4A format are transcoded to MP3. MP3 audio files and other files are transferred unchanged. Filenames are adapted where necessary to comply with the FAT32 format. If preferred, sync_music can also forcefully transcode all files in order to save disk space. Another operation mode applies volume normalization based on ReplayGain tags.

Transcoding is a time consuming operation, therefore the first run of sync_music can take several minutes. In subsequent runs however, it will only process files that changed in the source. To optimize the detection of file changes, the script stores and compares a hash build on a fixed size block at the beginning of each file.

Besides audio files, sync_music is also able to export M3U playlists to the destination folder. Absolute paths are hereby replaced with relative paths in addition to the FAT32 filename adaptations.

Dependencies

• Python >= 3.9
• FFmpeg (for transcoding to MP3)
• Mutagen >= 1.29 (for tag manipulation)

Installation

The first step is to install FFmpeg. Most Linux distributions offer packages that can be directly installed. On Ubuntu 18.04 or later there's an official package that can simply be installed using:

# apt install ffmpeg

Then sync_music can be installed from PyPI with:

# pip3 install sync_music

The following command installs the current development version:

# pip3 install https://github.com/fetzerch/sync_music/archive/master.zip

Usage

Quick start

The following basic command synchronizes all audio files from the source to the destination directory:

sync_music --audio-src=<FOLDER> --audio-dest=<FOLDER>

Additionally M3U playlist syncing can be enabled by specifying the path to the playlists:

sync_music --audio-src=<FOLDER> --audio-dest=<FOLDER> --playlist-src=<FOLDER>

Besides that sync_music supports a number of advanced options. A full list of supported options is available in the built in help message:

sync_music --help

Transcoding

The operation mode can be changed with the --mode parameter.

In transcode mode MP3 files are transcoded as well (instead of just copied to the destination):

sync_music --audio-src=<FOLDER> --audio-dest=<FOLDER> --mode=transcode

Transcoding MP3 files can lead to significantly smaller files if the source contains many 320kbps CBR MP3s as the target rate is 190kbps VBR. The drawback is that transcoding is slower and needs more CPU power.

The replaygain and replaygain-album modes apply (track or album) based volume normalization from ReplayGain tags when transcoding:

sync_music --audio-src=<FOLDER> --audio-dest=<FOLDER> --mode=replaygain

Transcoding modes require that the MP3 files can be decoded by FFMpeg without issues. Problematic input files can be analyzed and fixed for example with MP3 Diags.

Hacks

Some media players don't properly support album artist tags. This restriction can be bypassed by writing the album artist information into the artist field. This can be enabled by adding the --albumartist-artist-hack parameter.

Some media players don't properly support album artist tags, but they do support the composer field. This restriction can be bypassed by writing the album artist information into the composer field. This can be enabled by adding the --albumartist-composer-hack parameter.

Some media players don't properly support artist tags. This restriction can be bypassed by writing the artist information into the album artist field. This can be enabled by adding the --artist-albumartist-hack parameter.

Some media players don't properly support disc number tags with tracks numbered starting with 1 for every disc. The user typically wants to group them by disc and not by track position. This can be solved by creating a different album for each disc. With the --discnumber-hack option, the disc number is appended to the album field.

Some media players don't properly support track number tags containing the total number of tracks on the disk. With the --tracknumber-hack option, the track total is removed from the track number field.

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.