Cultured Perl: Fun with MP3 and Perl, Part 1

Ted writes "Every self-respecting computer and music fan needs to be able to manipulate MP3s -- the defacto standard for recreational digital music use. In this article, I'll look at ways to manage and manipulate MP3s (searching, tagging, renaming, commenting, etc.) using the autotag.pl application. I'll also take you through the application, illustrating how CPAN modules enable the application."

Comments

and like every Linux geek..

[rf0]

I'm going to say "Where the ogg version?" :)

Rus

Re:and like every Linux geek..

[Josh Coalson]

I'm going to say "Where the ogg version?"

Right here. Or here for FLAC.

Josh

Re:and like every Linux geek..

[Minna Kirai]

And if nobody converts their files to ogg's, why would manufacturers waste development time and costs putting ogg support into their products?

So they can have a superior format without the risk of Apple or Microsoft quadrupling the license fees 9 months down the line.

Actually, because Microsoft is pushing their own audio format, manufacturers will have a low-cost chance to push Ogg. They're going to have to expand the devices to recognize non-mp3 files anyhow... why not throw in the free integerized Ogg code while they're at it?

Another MP3 tagging library....

[tcopeland]

...written in Ruby, can be found right here. From the project page:

mp3taglib is a id3v1/id3v2 mp3 tagging library for ruby, based on id3lib. At
this early stage it already supports most of the fields of id3v2 tags. Mp3
encoding informations can also be retrieved.

Nice to know...

[jargoone]

It's nice to know you can do this, and I've used the modules referenced for custom fixes. But don't reinvent the wheel if you don't have to: EasyTag probably does 90% of what you would write something custom for.

Why stop with tagging?

[Dr. Zowie]

Perl (with PDL) is powerful enough to remix, comb-filter, compress, depop, noise-gate, and generally munge your mp3s as much as you want.

We're in an exciting time when many of the scripting languages are being augmented to be able to handle Real Data (Numpy is another example).

Re:Perl.com article

[blech]

To be fair, the MusicBrainz article for perl.com (that, full disclosure time, I wrote) doesn't cover as much ground as the Developer Works article, which seems to be going through all the steps needed to write an autotagger in Perl.

However, I was a little dissapointed that Teodor didn't spell out more of his reasoning for his choice of modules. I covered the (then) available Perl mp3 modules for a talk at YAPC::Europe this summer, and if you're not sure which modules to use, I'd suggest having a look at the slides (80K PDF) and notes.

In any case, I look forward to the second part of the article, to see how the script shakes out in the end.

Re:How come many Mp3's don't have this data?

[blech]

Generally, CDs don't have all the track information on the CD. RealPlayer, Windows Media, iTunes and so on all use a computed identifier of some sort, based on the length of tracks, typically, to look up the CD information from an online database.

Of course, because this means that *someone*, *somewhere*, ended up typing in the data, there are errors in a lot of the data. Most of the CD lookup databases are very bad at handling compiliations, and can have problems with any of the items of metadata other than title and artist (for example, 'year' often ends up as the year the CD is ripped, not the year the music was produced).

There aren't many programs that strip the data that's produced, though. Thankfully.