I'm going to bump this and try to provide a better description.
I would like to note that although DLNA support hasn't been confirmed for the PS4, I have a good feeling they will add it in sometime in the future - so maybe this isn't worth the development time.
That being said, as of right now you can only stream videos to your PS4 using the built-in web browser. This is accomplished through an HTML5 video player saved into an HTML document on your computer and hosted via a file server. The code in the document points to the video file, which is also hosted on your file server. The video must be MP4 (v:h264 a:aac). You can then point the PS4's web browser to your computer's file server via LAN IP address and the HTML5 player will stream the video file. The player I've been using allows for fullscreen, which works perfectly. In my testing I haven't encountered a single issue, and it even works flawlessly for high bitrate 1080p video content. I'm about to begin testing now on checking for Cinavia and I'll edit this post when I'm done.
So the feature suggestion I would make is a built-in paged web server for accommodating the PS4, which you can browse your shared folders and upon choosing a file, it loads a new page with an HTML5 player and begins transcoding the file (when necessary) to MP4. Either this, or a simple API built into the program to allow for a transcode request to be dumped to a local file and thus shared to an HTML5 player within the PS4 web browser.
Any input or thoughts on this suggestion?
Edit: Finished testing for Cinavia. I sent the same file simultaneously to my PS3 and PS4. The PS3 reported Cinavia protection while the PS4 continued to play. I did this test a second time with a different file as well with the same results. Conclusion is that the PS4 does not currently have Cinavia protection within its web browser.