Apple began its rebuttal case this afternoon, and it used a pair of former employees to argue against claims it had infringed Samsung's utility patents. Path employee Emilie Kim, formerly of the iOS software team, was up first to explain the nuances of the iOS Camera and Photos apps. She was followed by Dr. Paul Dourish, who had previously worked in Apple's research labs, and addressed several of the same subjects while also arguing that one of Samsung's patents was invalid outright.

Samsung's '893 patent has become known as the "photo bookmarking" patent, and covers the ability for a device to switch from a mode that displays images (think the picture playback mode on your point-and-shoot), to a mode where you can take pictures, and then back again — all without losing your place in your photo browsing.

App vs. mode

The patent language spells out these modes very specifically — "photographing mode" and "stored-image display mode" — which Samsung says is analogous to the iOS Camera and Photos apps. Dourish and Kim both disagreed, explaining that a mode was an overall state for a device, such as airplane mode, or the silent call mode that occurs when a user flips the switch on an iOS device. Apps, on the other hand, are "immersive" experiences, Kim said.

Not only do Apple devices not infringe upon the '893 patent, Dourish said, but the patent itself isn't valid due to prior art. He showed a patent granted to LG for cameraphones that predated Samsung's by a year. The LG patent, he explained, described the exact same functionality.

A Sony phone makes an appearance

Former employees weren't the only ones that Apple called to the stand, however. Dr. Tony Givargis took on Samsung's '711 music playback patent on a number of different fronts, first explaining that he didn't feel Apple devices infringed due to certain elements of the iOS software infrastructure. He followed it up with another prior art debunk, combining the Sony K700 phone (no, not that Sony phone) with a pre-existing patent to come to the conclusion that the invention described in Samsung's patent was obvious — and therefore the patent was invalid.

Samsung declined to cross-examine the witnesses, citing time constraints (each side was given only 25 hours of trial time, and both sides are running low). Judge Koh evidently felt that Samsung may have been engaging in some theatrics when it came to its time allotment, however. "I'm not going to allow the parties to file something that says you were unable to present witnesses," she said to Samsung's team, "because i think you made a strategic decision" on how the parties chose to use their trial time. Samsung spent almost 14 of its 25 hours cross-examining Apple's witness before it even mounted its own case. "You had to be disciplined about how time was spent," Koh said.