Sony detailed a bit more in regards to the PS4's UI today at GDC. For starters, the Xross Media Bar of the PS3 and the LiveArea UI of the Vita stay on those systems. The new UI for the PS4 "goes in new directions", said Chris Norden, Senior Staff Engineer at Sony.
Mockups of the new UI were to shown to give people an idea of the new interface. Up-to-date information is to be shown for all games, including DLC, videos, friend recommendations, social links and more.
The Friend system has been improved greatly over PS3, said Norden. As a side note, the social network features the use of true names. A player has two identities on the PS4 -- your user name and your true name. The true name will not be shown by default, but will be visible to those linked via Facebook or other trusted methods. Otherwise, you'll have to mutually agree to show true names (think Google and YouTube).
Here's some good news: the cap on the friends list has increased for PS4 over PS3, though no specific numbers were given.
So how about that Share button? Well, "Share" on the PS4 controller uses the system's hardware encoder, which is always recording the last several minutes of gameplay without using any additional system resources An example of a Share menu shows off the fact that you can upload a video to YouTube or Facebook easily -- background uploads can take place after you add a comment.
A new spectating feature lets you stream video of live gameplay, but you can also watch other people play. This is all built into the PS4 hardware, so no work is needed from developers. Users can type comments in real time, and developers can implement those comments via an API in their game.
Remote Play lets you connect your PS Vita to your PS4 via a local network or internet -- the screens are mirrored this time, unlike the PS3 and PSP. No system resources need to be allocated to Remote Play -- it's all built in. Remote Play can be started at any time, and Sony stated that they used code from Gaikai to make this feature work.
For the buttons that the Vita is missing from the PS4 controller, mapping will be supported. Multi-user support is important for the PS4, which is a vast improvement over the PS3. Multiple players can log in, earn trophies and more, just like LittleBigPlanet (finally!).
"Play during download" is a key feature of PS4 for digital games, so you don't have to wait hours to play a hot new release -- immediate play is the goal. The game data will be split into multiple chunks and will enable the player to start when the minimum amount of data has been pulled down to the hard disk. Developers will be encouraged to create this minimum package to start players off.
Finally, an official PlayStation App will come to the Android and iPhone platforms. The app will also work as a second screen for PS4 games (Smartglass?!).