Sony has made Vita Remote Play a necessary requirement for all PS4 games barring those that support specific hardware like PS4 Eye.
The news was first broken on Eurogamer via a development source and later confirmed on Twitter by PlayStation Worldwide Studios boss Shuhei Yoshida.
@mrdawe Yes, it's true unless the game requires specific hardware like the camera. It will be great to play PS4 games on PS Vita.May 29, 2013
Remote Play currently allows your Vita to connect to your PS3 and become two things: firstly, a controller and secondly, a TV. So you press buttons on your Vita as though it's a DualShock, the PS3 plays the game like normal, but then encodes the 'video out' as a video stream and sends it to your Vita's screen, either over local airwaves or the internet. This enables players to start games or videos on their home console and then continue playing them on the portable while on the go.
The neat feature wasn’t embraced like Sony - and many gamers – had hoped it would be, so today’s news is welcome. As Eurogamer notes, developers are unlikely to grumble about the new Sony mandate either. While PS3 Remote Play is based around software video encoding via the Cell's SPUs, meaning developers who use it have to sacrifice CPU time, PS4 features bespoke hardware video encoding for Remote Play and screen-sharing support powered by Gaikai's streaming technology. With these built into the new console's operating system, PS4 developers won’t suffer a performance penalty for using them.