How BitDek reads your tags

This guide explains exactly which metadata fields BitDek reads from your audio files, how different formats store the same information, and what happens when fields are missing.

The extraction process

When you import a file, BitDek:

1. Reads the raw metadata from the file
2. Applies folder-based fallbacks for missing fields
3. Determines the Album Artist (if not explicitly set)
4. Creates or matches database entries

The order matters. Fallbacks happen before album artist detection, which allows the detection system to work even when files have incomplete tags.

Fields by format

FLAC (Vorbis comments)

BitDek reads FLAC files using native Vorbis comment parsing. Field names are case-insensitive.

Core Track Fields:

BitDek Field	Vorbis Comment Name	Notes
Title	TITLE	Required for display
Sort Title	TITLESORT	For custom sort order
Artist	ARTIST	The track performer
Sort Artist	ARTISTSORT	For custom sort order
Album	ALBUM	Groups tracks together
Sort Album	ALBUMSORT	For custom sort order
Album Artist	ALBUMARTIST or ALBUM ARTIST	Primary album performer
Sort Album Artist	ALBUMARTISTSORT	For custom sort order
Track Number	TRACKNUMBER	Format: “5” or “5/12”
Disc Number	DISCNUMBER	Format: “1” or “1/2”
Total Tracks	TOTALTRACKS or TRACKTOTAL	Or extracted from TRACKNUMBER
Total Discs	TOTALDISCS or DISCTOTAL	Or extracted from DISCNUMBER
Genre	GENRE	Comma, semicolon, slash, or backslash separated
Compilation	COMPILATION	”1” or “true” for compilations

Date Fields (FLAC):

BitDek Field	Vorbis Comment Name	Notes
Release Date	DATE	Full date or year
Release Year	DATE or YEAR	Year extracted from DATE
Original Release Date	ORIGINALDATE	First release date
Original Release Year	ORIGINALYEAR	Or extracted from ORIGINALDATE
Recording Date	RECORDINGDATE	When recorded

Album Information (FLAC):

BitDek Field	Vorbis Comment Name	Notes
Edition	EDITION or VERSION	”Deluxe Edition”, “Remaster”, etc.
Primary Type	RELEASETYPE	Album, EP, Single, Compilation
Record Label	PUBLISHER or LABEL	Publishing label
Catalog Numbers	CATALOGNUMBER or LABELNO	Label catalog ID
Barcode	BARCODE	UPC/EAN code
Language	LANGUAGE	Album language
Country of Release	RELEASECOUNTRY	Release territory

Multi-Artist Fields (FLAC):

BitDek Field	Vorbis Comment Name	Notes
Track Artists	TRACKARTIST or PERFORMER	Additional performers
Composers	COMPOSER	Song writers
Lyricists	LYRICIST or WRITER	Lyric authors
Producers	PRODUCER	Production credits
Mixers	REMIXER or MIXER	Mix/remix credits

Classical Music Fields (FLAC):

BitDek Field	Vorbis Comment Name
Work	WORK
Movement Name	MOVEMENTNAME
Movement Number	MOVEMENTNUMBER or MOVEMENT
Movement Total	MOVEMENTTOTAL

MP3 (ID3 tags)

BitDek reads MP3 metadata through iOS AVFoundation, which handles ID3v2.3 and ID3v2.4 tags.

Core Track Fields:

BitDek Field	ID3 Frame	Notes
Title	TIT2	Track title
Sort Title	TSOT	For custom sort order
Artist	TPE1	Lead performer
Sort Artist	TSOP	For custom sort order
Album	TALB	Album title
Sort Album	TSOA	For custom sort order
Album Artist	TPE2	Band/orchestra/accompaniment
Sort Album Artist	TSO2	For custom sort order
Track Number	TRCK	Format: “5” or “5/12”
Disc Number	TPOS	Format: “1” or “1/2”
Genre	TCON	Split on delimiters. Null-separated v2.4 lists lose all but the first
Compilation	TCMP	iTunes compilation flag

Date Fields (MP3):

BitDek Field	ID3 Frame	Notes
Release Date	TDRL (v2.4)	Release date
Year	TDRC (v2.4) or TYER (v2.3)	Recording/release year
Original Release Year	TORY (v2.3) or TDOR (v2.4)	First release
Recording Date	TDRC	When recorded

Album Information (MP3):

BitDek Field	ID3 Frame	Notes
Edition	TXXX:EDITION or TXXX:VERSION	Custom frame
Record Label	TPUB	Publisher
Catalog Numbers	TXXX:CATALOGNUMBER	Custom frame
Barcode	TXXX:BARCODE	Custom frame
Country of Release	TXXX:RELEASECOUNTRY	Custom frame

Multi-Artist Fields (MP3):

BitDek Field	ID3 Frame	Notes
Composers	TCOM	Song writers
Lyricists	TEXT	Lyric authors
Mixers	TPE4	Remixer/mixer

Classical Music Fields (MP3):

BitDek Field	ID3 Frame	Notes
Work	TXXX:WORK or TIT1	Extended frame or Content Group
Movement Name	MVNM	ID3v2.4
Movement Number	MVIN	Format: “3/5”
Movement Total	MVIN	Extracted from “3/5” format

M4A/AAC (iTunes atoms)

BitDek reads M4A files through iOS AVFoundation.

Core Track Fields:

BitDek Field	iTunes Atom	Notes
Title	©nam	Track name
Artist	©ART	Track artist
Album	©alb	Album name
Album Artist	aART	Album artist
Track Number	trkn	Stored as number pair
Disc Number	disk	Stored as number pair
Genre	©gen	Single genre
Year	©day	Release date
Compilation	cpil	Boolean flag

Sort Fields (M4A):

BitDek Field	iTunes Atom	Notes
Sort Title	sonm	For custom sort order
Sort Artist	soar	For custom sort order
Sort Album	soal	For custom sort order
Sort Album Artist	soaa	For custom sort order
Sort Composer	soco	For custom sort order

These arrived in version 1.3.4. Earlier versions ignored the iTunes sort atoms, so libraries in Apple’s own formats never sorted by them even though the same tags already worked in MP3 and FLAC. If you tagged a classical or large collection in Apple’s formats and the sort order never took, update and re-import.

Multi-Artist Fields (M4A):

BitDek Field	iTunes Atom	Notes
Composers	©wrt	Song writers

Classical Music Fields (M4A):

BitDek Field	iTunes Atom
Work	©wrk
Movement Name	©mvn
Movement Number	©mvi
Movement Total	©mvc

Audio technical information

BitDek extracts technical details from the audio stream itself, not from tags:

Field	Source	Notes
Format	File analysis	FLAC, MP3, AAC, etc.
Codec	File analysis	Encoder used (e.g., “LAME 3.100”)
Bit Rate	Audio stream	In kbps
Sample Rate	Audio stream	In Hz (e.g., 44100, 96000)
Channels	Audio stream	1 (mono) or 2 (stereo)
Bits Per Sample	Audio stream	16 or 24 bit depth
Duration	Audio stream	Calculated from samples
File Size	File system	In bytes

These values appear in the Track Info sheet under “Audio Technical.”

Folder-based fallbacks

When a file lacks certain metadata, BitDek uses folder names as fallbacks. This happens automatically during import.

Album fallback

If the album field is empty:

• BitDek reads the parent folder name
• Example: /Music/Pink Floyd/Dark Side of the Moon/track.flac
• Album becomes: “Dark Side of the Moon”

Title fallback

If the title field is empty:

• BitDek uses the filename
• Track number prefixes are stripped (“01 - ” or “01.” patterns)
• Example: 01 - Speak to Me.flac becomes “Speak to Me”

Artist fallback

If the artist field is empty:

• BitDek checks the grandparent folder (assumes Artist/Album/Track structure)
• Example: /Music/Pink Floyd/Dark Side of the Moon/track.flac
• Artist becomes: “Pink Floyd”

Folder names BitDek ignores

Both fallbacks skip folder names that describe storage rather than music. A folder called “Downloads” is not an album, and “Music” is not an artist.

The ignored names, matched without regard to capitalization:

music, audio, songs, tracks, albums, itunes media, itunes music, downloads, documents, desktop, library, audiofiles, resources, assets, temp, temporaryitems, cache, caches

Anything beginning with a dot is skipped too, along with empty names.

Worth knowing if your folders are named this way: an album folder literally called “Albums” produces no album name at all, rather than an album called “Albums”. Tag the file instead of renaming the folder.

Edition fallback

If the edition field is empty, BitDek attempts to extract it from the album title using common patterns:

• Parentheses: Album Name (Deluxe Edition) → Edition: “Deluxe Edition”
• Brackets: Album Name [2023 Remaster] → Edition: “2023 Remaster”

This works for all supported formats.

Why fallbacks matter

The fallback system allows BitDek to organize files that lack proper tags. But fallbacks have limits:

• They assume a specific folder structure (Artist/Album/Track)
• They can’t distinguish compilation albums from regular albums
• They may produce incorrect results for unusually organized collections

For the best experience, properly tagged files beat folder-based guessing.

Extraction order (technical detail)

The extraction sequence is critical for correct album artist detection:

1. Extract raw metadata from file tags
2. Apply folder-based fallbacks (album, title, artist)
3. Three-Tier Album Artist Detection
4. Multi-genre parsing (FLAC only)
5. Artwork extraction
6. Database entity creation/matching

Folder fallbacks occur BEFORE album artist detection. This matters because the detection system queries existing tracks by album name. Without the album fallback first, tracks without album tags would skip detection entirely.

See Album Artist and compilations for details on the three-tier detection system.

Multi-value fields

Genre handling

Genre fields go through the same splitter in every format. BitDek recognizes four separators:

• Comma: Rock, Alternative (preferred)
• Semicolon: Rock;Alternative
• Forward slash: Electronic/Ambient
• Backslash: Electronic\Ambient

Each value becomes a separate genre in your library. A track tagged Jazz, Fusion, Instrumental appears in all three genre categories, whether it’s a FLAC, an MP3, or an M4A.

FLAC adds one capability the others don’t have. Vorbis comments allow repeated GENRE tags, and BitDek reads every one, splitting each in turn.

Multi-artist fields

FLAC supports multiple values for artist-related fields. When you have multiple composers or performers, separate them with commas, semicolons, or slashes:

• Composers: John Lennon, Paul McCartney (preferred)
• Producers: George Martin, Phil Spector

BitDek also recognizes collaboration patterns like “feat.”, “featuring”, “with”, ”&”, and “vs.” when parsing artist names. Each name becomes a separate artist entry in your library.

Where multi-value genres get lost

ID3v2.4 lets a text frame hold several values as a null-separated list. iOS AVFoundation truncates that frame at the first null byte, so BitDek receives only the first genre. MusicBrainz Picard writes this form by default from version 2.9 onward.

Setting your tagger to ID3v2.3, or typing your genres as one delimited string, avoids it entirely. See Multi-genre tagging.

Special cases

Compilation detection without tags

Some older files lack the compilation flag but are clearly compilations. BitDek detects this by watching for multiple artists within the same album folder. See Album Artist and compilations for the full detection process.

Track numbers with leading zeros

BitDek handles track numbers in various formats:

• 5 → Track 5
• 05 → Track 5
• 5/12 → Track 5 of 12
• 05/12 → Track 5 of 12

Leading zeros are normalized to integers.

Date vs. year

Some taggers use full dates (2023-03-15) while others use just the year (2023). BitDek extracts the year portion from full dates for consistent display.

Case sensitivity

Artist and album matching in BitDek is case-insensitive. “Pink Floyd” and “pink floyd” are treated as the same artist. The display preserves the case from the first imported file.

Sort fields take precedence

Whatever a sort field says, BitDek uses it, exactly as written.

Where that shows up most is the leading-article rule. BitDek files past a leading The, A, or An on anything that carries no sort tag, and a file that does carry one skips the rule regardless of how the setting is left.

An empty sort field is not a neutral value here. It is the absence of instruction, and that absence is precisely what lets the article rule step in. Fill it and the rule stops applying to that item. Browsing your library covers the setting and how to use this as a per-item override.

Verification tips

To check how BitDek will read your files:

1. Import a sample of files from your collection
2. View the track details in BitDek (tap the info button)
3. Compare against what your tagging software shows
4. Look for discrepancies in album artist, genre, or classical fields

If you see unexpected results, the most common causes are:

• Missing album artist tag (triggers fallback detection)
• Multiple genre values in MP3 (only first appears)
• Unusual folder structure (affects fallback accuracy)

Further reading

• Album Artist and compilations - Three-tier album artist detection
• Multi-genre tagging - Working with multiple genres in FLAC
• Classical music tags - Work and movement field details
• Recommended tagging tools - Software for editing your metadata