Stressed by compressed media files

If you're like most digital music users, you've probably done a double take when listening to certain songs in your collection that sound a bit strange. Maybe it's a general tinnyness, or a cymbal that seems too sharp, or complex arrangements that are muddled. It definitely isn't as clear as the original CD.

The cause is an issue that Apple and most other major players in the digital music industry don't like to admit: poor compression formats. Songs bought through iTunes or ripped from your own CD collection are compressed to save space and bandwidth, and many of the default formats simply cannot do justice to the original song. Many home computers let you burn mp3s, but the standard setting is 128 kbps, which results in a significant loss of quality when the song is encoded. iTunes uses 128 kbps AAC, a different compression format which includes DRM features to restrict users from sharing AAC files but has an even greater quality loss. You may not notice listening to your iPod on the subway or at the gym, but playing the songs through a decent set of speakers will reveal flaws that can make certain songs unlistenable.

Audio purists insist on lossless formats like .wav (Windows), AIFF (Mac), or "Red Book Audio" (standard CDs) but see compression as a necessary evil to enable storage and playback on today's computers and digital devices. Still, they have far higher standards for compression and future usability than what's offered by iTunes, as reported in this Wired article. The mp3 standard is seen as having greater longevity than AAC or other proprietary formats, and audiophiles prefer using the so-called LAME encoder at higher bit rates to compress music files.  At home I use iTunes, and burn mp3s using variable bit rate encoding at the highest possible setting -- generally between 190 and 210 kbps. It's not perfect, but I don't have unlimited storage space on my iMac or iPod, either.

Incidentally, the compression issue isn't only limited to audio files. Video compression is important not only to people downloading clips of TV programs to iTunes, but also to film buffs who want to watch old favorites on their new flat-screen TVs. In parts of Asia the older Video CD format is popular, but the quality is terrible -- films are encoded using the mpeg 1 format, which frequently leaves smudges around moving figures.

DVDs use the newer and more able mpeg 2 standard, but there are still some quality problems. I was watching the reissued Bambi DVD with my daughter, and the format couldn't handle one scene, in which drops of are falling on a the surface of a pond. The subtle effect designed Disney's animators was lost in a sea of corrupted white pixels. The new high-definition DVD formats are promising, but adoption will be dampened until the ongoing standards battle is resolved.