Episode Details

This show has been flagged as Clean by the host.

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01 Introduction

In a response to a post on a previous episode, I said that I would take a look at ID3 tags.

ID3 tags are text information that is added to an MP3 audio file, such as the author, date, name, and other information.

02

While I am at it I will also look at Vorbis comments, which perform a similar function for vorbis, the container format for "ogg" audio files.

As example audio files, I will use a recent HPR episode, hpr4678 in both mp3 and vorbis formats plus also one from another podcast as well.

03

There is Free Software which you can use to view, edit, or remove both types of tags or comments, and I will describe how to use it in this episode.

04

I will cover how to view tags and extract the text information, as well as how to strip the tags from a file and why you may wish to do so under certain very specific circumstances.

I won't cover how to add to or edit tags in an MP3 or OGG file, as that is a more involved subject that I don't have much experience with.

05

I will mainly talk about ID3 MP3 tags rather than vorbis comments for the simple reason that the situation with MP3 files is an utter mess while vorbis comments are very straightforward and so there isn't as much to say about them.

06

As often happens when researching a subject to write a podcast script, I have learned quite a bit that I didn't know previously, and discovered that things that I thought I did know were wrong.

I hope that you may learn a few things from this episode that you didn't know previously either.

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07 Background

I won't go over the detailed history of ID3 tags, as I don't have a reliable source for this.

Briefly however, so far as I can determine, there is no official independent standard for ID3 tags or vorbis comments.

Both seem to be more in the nature of a convention that was created by an unofficial group of contributors rather than something issued by a standards body.

08

However, I don't see the lack of a conventional standards body as necessarily a problem with respect to the use of ID3 tags or vorbis comments.

I just am not familiar enough with the industry to know who to regard as being an authoritative source when it comes to the history and development of them

Since I am unsure as who to credit with what developments, I will avoid that sort of detail.

09 ID3 Tags

There is a web site with the URL of ID3.org that seems to have the best reference material on the topic of ID3 tags.

According to this site, the term "ID3" means "IDentify an MP3".

10 Vorbis Comments

For vorbis, the reference site seems to be xiph.org.

Although the implementation details may differ from ID3, from our perspective as podcast listeners, they can be seen as more or less equivalent in terms of what I am going to address here.

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11 ID3 Details

Versions

One of the problems with ID3 is that there are multiple incompatible versions, particularly from the very early days.

ID3v1 tags are located at the end of the audio file in the last 128 bytes.

This was done for compatibility reasons to allow early MP3 players to simply ignore the tags if they didn't know how to deal with them.

The tags would simply appear as a short burst of static from the perspective of these early players.

12

ID3v2 moved the tags to the start of the MP3 file to allow players to