New checks:

• Trailing or leading spaces
• Any non-space white spaces
• Multiple consecutive spaces

They should apply to title, album, artist & albumartist.

Mutli disc albums should be flat and track numbers and totals should be across all discs. Disc numbers can still be set.

Artist A - My Album

and

Arist B - My Album

will hash to the same album and produce incomplete_album errors.

Either hash by directory instead of album or hash by a pair of album and artist (which will probably interfere with various artist handling).

Currently checks only allows two digit track numbers 01/10.

Enhance disc collection validation (e.g. the structure and sequence of the disc tag).

Allow:

• 1/3
• 04/12
• 10/12

Disallow:

• 02/04 (superflous padding)
• 100/200 (there is no such thing)
• 1/02 (inconsistent padding)
• 2/12 (inconsistent padding)
• 02/4 (inconsistent padding)

Make sure titles and album names use sentence case

Make sure each folder has one properly names cover image

Make sure all covers are of type Front Cover.

Make sure file names adhere to a convention

Probably need to refactor meta data collection first in order to solve this.

So, here's an attempt to plan required structures:

Groups of checks

Tag information

Genres

Checks the relation between artists and their genre

Genre ⟵ Artist

1. multiple_artist_genres: not more than one genre per artist

Albums

Checks all files in relation to their album

Album ⟵ File

1. Track inconsistencies incomplete_album
2. Multi-disc inconsistencies incomplete_collection
3. ID3v1 to ID3v2 truncation truncation_warning
4. Inconsistent year
5. Inconsistent album art (compare checksums)

Files

Errors for a particular File are assigned to its Album or Directory.

File ⟵ Frame

1. Missing frames missing_*
2. Invalid encoding mp3_invalid_encoding
3. Obsolete frame version (ID3v1 or ID3v2.3) mp3_id3v1, mp3_id3v2_obsolete
4. Invalid art type/size/count mp3_invalid_art_type, mp3_invalid_art_size, mp3_multiple_art
5. Invalid format (regex for track/disc frames) mp3_invalid_track, mp3_invalid_disc

File system

Each Album belongs to a Directory.

Album ⟵ Directory

1. Make sure a directory containing an album also contains cover art fs_missing_cover
2. Albums should be in exactly one directory fs_multiple_album_directories
3. Parent directories of album directories must resemble the album-artist frame fs_invalid_artist_directory

Collection of required information

File-System

1. Find a media file and store in a map: Directory ⟵ File.
2. For each Directory, look for file system cover art fs_missing_cover
3. Read tag information for each Files in 1. and attach a map: Directory ⟵ File ⟵ Tag
4. Missing frames missing_*
5. Invalid encoding mp3_invalid_encoding
6. Obsolete frame version (ID3v1 or ID3v2.3) mp3_id3v1, mp3_id3v2_obsolete
7. Invalid art type/size/count mp3_invalid_art_type, mp3_invalid_art_size, mp3_multiple_art
8. Invalid format (regex for track/disc frames) mp3_invalid_track, mp3_invalid_disc

Tag-Tree

1. Map Genre ⟵ Artist
2. Map Genre ⟵ Artist ⟵ Album
3. Map Genre ⟵ Artist ⟵ Album ⟵ Song
4. Map Genre ⟵ Artist ⟵ Album ⟵ Song ⟵ Tag

Simplification

Genre ⟵ Artist ⟵ Album ⟵ Song ⟵ Tag
|
Directory ⟵ File

or better:

Genre ⟵ Artist ⟵ Album/Directory ⟵ Song/File ⟵ Tag

Requirements

Each report must at least specify the directory so the user knows where to look for the error.

• Errors found while populating File-System either have Directory or File, so those are covered.
• Errors between Genre and Artist can occur across multiple Album/Directorys and need to report using the first encountered.
• Errors between Album and Song each have a corresponding file system node attached (Directory and File).

Various artists

The following relation does not hold:

Artist ⟵ Album/Directory

because

Album/Directory ⟵ Artist

Solution

So we actually need two trees forming a single one:

Album/Directory ⟵ Song/File ⟵ Tag
Album/Directory ⟵ Genre ⟵ Artist

This way the corresponding Directory is always accessible. The two branches do not share checks.

Requires some kind of light weight HTML template.

Detect multiple albums per directory or multiple directories per album.

Use a map and report an error when adding a different value to the same key or an existing value to a different key. An album must belong to one directory and a directory must belong to one album.

The error multiple_artist_genres should not apply to albums with an album artist of [Various Artists].

Make sure discnumbers are in format <num>/<total> or empty.

Make sure each album has only one media type.

Make sure containing directory adheres to naming scheme.