Richard Farrar's Blog

Album or cover artwork can easily be embedded within MP3 files via ID3 tags. However, the ID3 specification caters for over 20 different image categories. So which is the best image category to choose, and is it ever worth embedding more than one image into your MP3 files?

Since the release of version 2 of the ID3 tag specification over ten years ago it’s been possible to add album artwork to your collection of MP3 files. This feature of the ID3 specification is now pretty well supported. Most MP3 players with a screen capable of displaying graphics (be they software or hardware  based), now support this feature.

However, as usual with these sort of things, MP3 player manufacturers tend to implement the ID3 tag standard in subtly different ways. This inevitably leads to unpredictable results for the user, particularly when displaying album art.

Embedding Images into MP3s

If all this talk of ID3 tags leaves you a bit cold, then it may be worth pausing for a moment to read my previous post on ID3 tags in MP3 files before proceeding, as they are fundamental to our further discussions.

Embedding images into MP3 files is fairly straightforward and indeed might be accomplished automatically for you by your CD ripping software. If this is not the case, then you will need a special piece of software called a tag editor to help with the task. There are lots of tag  editors available for a host of operating systems, with some good free ones available. My personal favourite is Mp3Tag.

If you want to know more about adding cover art to your MP3 files, the best image format to use and what image size you should consider using, then check out my previous post on embedding album art in MP3 files.

ID3 Artwork Options

The present ID3 standard (version 2.3.0) lists 21 different images that can be embedded within an MP3 file. In practice only one image is ever usually embedded, although an MP3 track could technically have 20 images (only one of the icons #2 or #3 can be embedded at a time). However, the space taken up by the images in such a file would become quite significant compared to the audio data.

The images available to choose from are:

1. Other
2. 32×32 pixel icon (PNG only)
3. Other file icon
4. Front Cover
5. Rear Cover
6. Leaflet page
7. Media (e.g. label side of CD)
8. Lead artist, Lead performer or Soloist
9. Artist or Performer
10. Conductor
11. Band or Orchestra
12. Composer
13. Lyricist or Text writer
14. Recording Location
15. During Recording
16. During Performance
17. Movie or Video screen capture
18. A Bright coloured fish
19. Illustration
20. Band or Artist Logo
21. Publisher or Studio Logo

There are two notable exceptions in the above list that are a little different from the others:

• The second option (#2) only allows images in the PNG format and images which are sized 32 by 32 pixels for use as a small icon.
• The eighteenth option (#18) in the list; a bright coloured fish! Some loony tune obviously decided that this was a good idea for a formal specification. Need I say more?

So, for all essential practical purposes, the list really has 20 options (ignoring the brightly coloured fish), or if you are just considering images of unrestricted size, then it has 19 options.

Support for ID3 Images

MP3 Players

Not all MP3 players are created equal when it comes to displaying ID3 images. For example, the Creative Zen Vision: M, while having a large colour screen capable of displaying pictures, does not seem to display any of the ID3 images as far as I can tell; no matter which image tag is used.

The basic Creative Zen displays the ID3 image from the last track in a folder, but insists on using this same image for all tracks in the folder, no matter whether they have different artwork embedded within them or not.

Software Players

Windows media player seems to display any ID3 image correctly, but providing there’s only one image in a track. If a track contains more than one image, it will default to the Front Cover image. Quite how you’re supposed to see the other images, I really don’t know, but at least this seems a sensible fall back position.

Podcasts

A lot of podcasts seem to use the Other image tag (#1 from the above list) for their artwork instead of the Front Cover option. I’m not really sure why this is, other than that their software defaults to this option. My preference would be for the Front Cover tag in this circumstance, but I’d be interested to see what the general consensus is on this.

Test your Player

Having tried a few players and found them to be wanting in their handling of ID3 images, I decided to do a structured test on those I had available to me.

Test Images

In order to test the various ID3 image tags on a range of players, I produced 21 different images corresponding to each of the image tags. Each image is a 300 x 300 pixel jpeg (except the 32 x 32 pixel PNG icon):

If you’d like to use these images yourself for your own experiments, you can download all 21 as a zip file. Each individual image is approximately 25kB in size:

• ID3-Images.zip (246kB)

Test MP3 Tracks

In order to test these images on an MP3 player, they each needed to be embedded into an MP3 file with the appropriate ID3 image tag associated with the image.

My tag editing software doesn’t support the 32×32 icon image tag or the nonsensical fish tag, so I ended up creating 20 separate MP3 files: the 19 basic image tags plus one MP3 containing all 19 images in the one track.

The MP3 track including the 19 separate images in the one file ended up with a resultant file size of 911kB for a 26 second 128kbps MP3!

• 21 – ID3 Image – All Images.mp3 (911kB)

If you’d like to use these MP3 files for yourself to test your own MP3 player’s performance in this respect, you can download all 20 as a zip file:

• ID3-Image-Test-MP3s.zip (2.5MB)

Report Back

If you’ve found these files useful and end up discovering some quirks with your particular player, please leave a comment so that others can benefit from your findings.  You never know, it may spur a manufacturer into updating their firmware to fix the problems and make their players fully compliant for future users.