July 11, 2007

Backing up Music CDs

I’ve recently become interested in backing up my CD collection. A lot of my favorite CDs have suffered from repeated loading into my car CD player with its damaging feed mechanism. Some will need to be replaced, but hopefully I can back most of them up before they are completely ruined. I’ve ripped all of them at one point or another in various formats, compression rates, and with various ripper software packages, but I never put much thought into making accurate back-ups.

Lossless Storage with FLAC

One thing I knew going into this project is that I would need to find a lossless data storage format in order to have a perfect back-up. FLAC appears to be the ideal solution. It is lossless (meaning that FLAC-compressed data can be decompressed back to the exact original) and it has a respectable compression ratio for this type of compression. Also, FLAC is pretty well supported by both desktop music software and portable media players. Finally, FLAC is open source. Therefore, I have little worry that the file format will become obsolete and unusable years down the line. Now FLAC isn’t supported on everything, and it takes up a lot of space. However, the idea is that from your perfect back-up you can transcode to another format such as MP3 for storage on an ipod, for instance. If newer formats come into existence down the line, you can again transcode to the newer format (so long as you maintain the original FLAC back-ups). You never have to worry about re-ripping your CDs with this approach.

Best CD Ripping Software?

The next order of business is the actual ripping of the CDs. Unfortunately, getting the music off of a CD accurately is not as simple as just copying a file from the disc to your hard drive. CDROMs can literally get off track while reading, misread due to dirt and grime, or encounter other kinds of problems. The ideal CD ripping software should be able to recognize problems and reread the CD or apply corrections to the data stream as needed.

Exact Audio Copy (EAC) does this, and is generally the favorite tool of audiophiles (at least according to my research). Unfortunately, EAC is closed source and only runs under Windows. The open source CD Paranoia (CDP) is available for Linux but doesn’t have all the features of EAC. CDP is command-line only; however there is an excellent Gnome-based GUI app that uses CDP called Grip. Even if you are using Linux, EAC can be run successfully via WINE.

If you want the most accurate rips possible, you should also use Accuraterip with EAC. Accuraterip can run as a plug-in for EAC and works by comparing a fingerprint (CRC check) against a remote database of fingerprints that many other users got when ripping the same CD. This approach lets you determine with a high level of certainty whether you have a perfect rip of your CD.

Most Accurate Back-up

Another issue regarding ripping is whether you rip a CD as individual tracks on the disc or as a continuous image of all the audio on the disc. It’s not as much of an issue as it used to be, but some MP3 players will have noticeable pauses or other audio anomalies between tracks while playing several songs in a row. (Many recent players can handle this situation with unnoticeable or barely noticeable transitions.) One solution is to rip the entire CD as one big file. There is also the fairly rare issue of “hidden” tracks on CDs. If you want to make sure to capture all the data on the disc, you’re often better off ripping as one big file.

The problem with this single big file approach is that individual tracks are no longer denoted. However, a solution is available with the use of CUE sheets. This is a secondary file that provides a table of contents for the position of the beginning and end of each track. All in all the issues necessitating single file backup plus CUE sheets probably aren’t that big a deal but it appears many audiophiles do this for perfect CD back-ups.

While ripping as a single FLAC file with an accompanying CUE sheet (I’ll just call this FLAC-CUE from now on) is a great way to back up a CD, it is unfortunately less than ideal for playback. Very few software or hardware media players can handle CUE sheets coupled with any type of audio file. The popular Linux player, Amarok, can handle CUE sheets, but it only uses them to show you the name of the current song within a single large FLAC file. You cannot jump straight to any particular track, nor can you shuffle the songs. Fubar2000 for Windows is apparently one of the few players that have full support for CUE sheets.

The only real practical solution is to transcode from FLAC-CUE to single tracks of another format. The obvious disadvantage is that if the back-ups of your CDs are already on network attached storage then transcoding will significantly increase the amount of disc space used and will be largely redundant. Additionally, you won’t be using the high quality available to you unless you transcode to individual tracks of FLAC thus doubling the the already lofty storage requirements for your library. This problem isn’t really a big issue if you only use a portable media player for listening since you’ll have to copy the songs over to the player anyways, but it is an issue if you like to use a software player. I am hopeful that Amarok will eventually add full support for FLAC-CUE! If you don’t consider yourself a hardcore audiophile, you may want to simply back up to individually encoded FLAC files. That way, you’ll avoid all these playback issues encountered with the FLAC-CUE approach.

Copy Protection Issues

Lastly, I want to point out I’m not really sure what solutions there are for copy protected CDs. It may be that EAC already has workarounds for any copy protection. I have read anecdotes about certain CDROMs (such as one manufactured by Sony) detecting that they are being used for CD ripping and triggering a machine panic to halt your computer.

Editor’s note: Original link no longer resolves; updated to an archived copy from the Wayback Machine.