This past Friday, as part of Apple’s ongoing iPod antitrust lawsuit, former Apple engineer Rod Schultz took the stand and testified about Apple’s efforts to prevent the iPod from playing music files downloaded from from competing services.

The Wall Street journal reports:

A former iTunes engineer testified in a federal antitrust case against Apple Friday that he worked on a project “intended to block 100% of non-iTunes clients” and “keep out third-party players” that competed with Apple’s iPod.

Echoing arguments previously raised at trial from the likes of Eddy Cue and Steve Jobs, Schultz said that the security oriented iTunes updates Apple implemented in the mid-2000s were less about blocking competition and more about keeping the iPod/iTunes ecosystem safe, secure, and reliable.

Apple many years ago caught a lot of flack over its FairPlay DRM, but testimony delivered during this trial suggests that Apple’s behavior with iTunes had more to do with complying with stringent record label contracts than with anything else. As Jobs relayed via a videotaped deposition conducted in April of 2011, Apple’s music contracts were “black and white” and stipulated that record labels could pull their music from iTunes in the event that someone was able to break Apple’s DRM.

“We were very concerned with somebody like Real [Networks] promising customers that they would have compatibility, when in the future they might not,” Jobs explained. “That’s not something we could guarantee. So we could get sued by all these people.”

Plaintiffs are seeking US$350 million in damages on the grounds that Apple illegally stifled competition so that they could, in turn, keep the price of iPods artificially high. The jury is expected to begin deliberating sometime this week.