1. Overview

Recursively mirror a directory tree of FLAC audio files to AAC/OGG/MP3. Source files can be filtered (by sub-directory, or full path) in order to limit the files converted. The script will also attempt to retain all meta-data fields in the output files.

1.1. At a Glance

• Mirror directory tree of FLAC files audio files to AAC/OGG/MP3 (re-encoded using NeroAacEnc, oggenc, or LAME).
• Filter source tree using one or more sub-directory paths.
• By default, will only re-encode missing or out-of-date AAC/OGG/MP3 files.
• Optionally deletes orphaned output files.
• Multi-threaded encoding ensures full CPU utilization.
• Supports transfer of FLAC meta-data including title, artist, album.
• Converts FLAC replaygain field to Apple iTunes Sound Check.
• Optionally resizes and embeds album cover art JPEG files to destination files.
• Optionally copy cover art to destination directories.

1.2. Usage Model

• Hard disk space is cheap, but flash-based media players are still limited in capacity.
• Create a lossy encoded “mirror” of your music files for portability.
• Setup a daily cron job to always keep your FLAC and AAC/OGG files synchronized.
• Re-encode your FLAC library to different AAC/OGG bit-rates in one command.

1.3. Running and Options

Flacsync is run from the command-line, using the following format.

flacsync [options] BASE_DIR [SOURCE ...]

BASE_DIR

Define the root path of a directory hierarchy containing desired input files (FLAC). A mirrored output directory will be created in the deepest path, parallel to BASE_DIR, and named after the selected output file extension.

For example, if BASE_DIR is /data/flac, the output dir will be /data/aac.

SOURCE ...

Optional dir/file argument list to select source files for transcoding. If not defined, all files in BASE_DIR will be transcoded. The SOURCE file/dir list must be relative from BASE_DIR or the current working directory.

--version	show program’s version number and exit
-h, --help	show this help message and exit
-c THREAD_COUNT, --threads=THREAD_COUNT
	set max number of encoding threads [default:2]
-f, --force	force re-encode of all files from the source dir; by default source files will be skipped if it is determined that an up-to-date copy exists in the destination path
-t ENC_TYPE, --type=ENC_TYPE
	select the output transcode format; supported values are ‘aac’,’ogg’,’mp3’ [default:aac]
-o, --ignore-orphans
	prevent the removal of files and directories in the dest dir that have no corresponding source file
-d DEST_DIR, --destination=DEST_DIR
	define alternate destination output directory to override the default. The standard default destination directory will be created in the same parent directory of BASE_DIR. See BASE_DIR above.
-r, --resize	enable resizing of cover art; by default the art that is found will be saved to file without resizing.
-j, --copy-cover-art
	in addition to embedding cover art, copy image file directly to the desination sub-folder.

1.3.1. AAC Encoder Options:

-q AAC_Q, --aac-quality=AAC_Q
	set the AAC encoder quality value, must be a float range of 0..1 [default:0.35]

1.3.2. OGG Encoder Options:

-g OGG_Q, --ogg-quality=OGG_Q
	set the Ogg Vorbis encoder quality value, must be a float range of -1..10 [default:5]

1.3.3. MP3 Encoder Options:

-m MP3_Q, --mp3-quality=MP3_Q
	set the Lame MP3 encoder quality value, must be a initeger range of 0..9 [default:3]

1.4. Examples

1. Encode a directory of FLAC files to AAC. Output file will be written to /music/aac.

   flacsync /music/flac
   cd /music/flac; flacsync .

2. Encode a directory of FLAC files to AAC. Output files will be written to /ipod.

   flacsync -d /ipod /music/flac
   

3. Encode a directory of FLAC files to high-quality OGG, using 4 CPU threads.

   flacsync -c 4 -t ogg -g 9 /music/flac

4. Force re-encode two albums of FLAC files, even if the AAC files exist.

   flacsync -f /music/flac artist1/album artist2/album
   cd /music/flac; flacsync -f . artist1/album artist2/album