Though the PlayStation 4 wont work with DLNA and MP3 playback right out of the box, it's been confirmed this week by Sony that they'll certainly be looking at incorporating the features in the near future. Due to overwhelming response to the idea that neither DLNA or MP3 playback would be available on the gaming console, Sony seems to have turned a corner on their aim to have them work.
Speaking this week with Giant Bomb, Sony's President of Worldwide Studios Shuhei Yoshida made clear that they'd be rolling forward with possible updates for both MP3 playback and DLNA compatibility in the future for PlayStation 4. Yoshida also suggested that the lack of MP3 playback had nothing to do with the likes of Music Unlimited being a feature on the console - they simply didn't think MP3 playback was an item users wanted for the future.
While Yoshida's suggestion doesn't guarantee that DLNA and/or MP3 playback will be available eventually, it does shine a healthy light at the possibility. He suggested that he and the development team "always thought" they'd be incorporating DLNA and MP3 playback eventually, they just didn't foresee prospective gamers reacting to the news so vehemently.
Yoshida suggested that before the news was released that MP3 playback and DLNA compatibility was released, there wasn't any clue for the development team that these were any sort of "must have" features. Yoshida went on to imply that it was at the point that people started to get "really made" and say "I canceled the pre-order!" that Sony decided to bring the fans what they want.
It's no longer a matter of "if", but of "how" and eventually "when" they'll be implementing these features. Again, no guarantee - but it's looking good!