bliss and the three Cs

Analyzing Financial Data

The three Cs of music library management are three measures by which the tidiness of your music library is judged. This blog post describes, at the time of writing, how bliss tidies your music collection with reference to the three Cs. I also identify areas where bliss could be improved to further tidy your music collection.

The three Cs refer to the state of your music metadata and ancillary items like album art. These are the essential building blocks of a music library, because they help us find, browse and search our music collections when we want to play music. They are central to our music experience: when they become untidy it's obvious, and the more untidy they get the more you want to do something about it.

What are the three Cs? They are completeness, correctness and consistency.

Update (2014): I've since written a more detailed series of posts on the three Cs. Check them out:


Completeness is the completeness of your album art or metadata. For instance, does each piece of music you have in your music library have a year tag? What about album art, are there any pieces that are missing?

The most obvious and mature functionality in this area is bliss's album art finder. bliss recognises where your album art is incomplete and, where art is missing, finds, downloads and installs it.

More recently I added functionality to fill in missing genre and year tags. These data are important for browsing your music collection and choosing which tracks to play. bliss looks up this information on MusicBrainz and, coming soon, Wikipedia.


Where can completeness be further improved? Well we can look into auto-tagging more types of tag for starters. Most difficult are music albums that are completely untagged, and for this we would need an auto tagger that uses an audio fingerprint.

There are a host of other metadata that would be useful to be auto tagged. Lyrics, BPM and ReplayGain volume normalisation would be further ideas.

bliss could also make sure your music library is mirrored in different file formats. Having your music in different file formats is useful when using different music players that might not support certain file types, or it may be advantageous to have copies of your music in more compressed form. Maintaining mirrors would mean you never need to perform a manual conversion again!


Correctness refers to whether tag values are definably correct or not. This usually involves some reference of agreement from an external source of data. For instance semantic correctness refers to whether a piece of metadata is knowingly true (e.g. the year an album was released). Syntactic correctness refers to the way a tag is used. For instance, the character encoding or the use of alphabetic characters when only numeric characters are allowed.

This is probably bliss's weak area. In terms of semantic correctness there is no way in bliss to identify a piece of metadata as 'incorrect' just yet. For instance, bliss could double check your current year tags against an online music database, marking those that differ and offering to correct them.

Similarly, there's little to enforce synactic correctness in bliss. One example may be to enforce specific types of text encoding, as some tag formats do not support specific encodings.


This is bliss's strong suite, which is unsurprising, because it's my main area of interest and the original reason I wrote bliss.

Consistency is generally concerned with the semantic meaning of tags, and whether they are used consistently throughout your music collection. For example, do your year tags denote original release year, or re-release? Having different approaches to the same tag makes using the tag pretty meaningless, so bliss aims to straighten out these inconsistencies.

bliss attempts to achieve consistency of genre tags by allowing you to enforce 'permitted' genres. Albums that fall outside these genres are analysed to produce an alternative, permitted genre you may wish to change the album to.

With album art, too, bliss attempts to enforce consistency of art size and whether art is embedded or not.


There's also music file organisation to make sure that files and folders in your music collection are consistently structured, given the tags embedded within the music files.

One way in which these features could be improved is by automating them. So, for example, the addition of ID3v2 tags and the shrinking of art that is too large, in terms of bytes could be automated. Currently bliss simply tells you the problem and offers a one click manual fix, which is about as easy as I could make it without automating it.

It's clear that bliss's main focus so far has been on improving your music libraries' consistency. However, I have concerns with my own music library in other areas, such as making sure all the metadata I need is complete and correct, and it's clear from the bliss ideas forum that there are other areas that bliss could cover.

I'm looking forward to working on some of these new and exciting features!

Thanks to Dave Dugdale, Dyanna and Brett L. for the images above.
tags: bliss digital music
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The Music Library Management blog

Dan Gravell

I'm Dan, the founder and programmer of bliss. I write bliss to solve my own problems with my digital music collection.