I checked the DVD playback quality of my PS4 after installing today's update (1.60) which is supposed to feature an improved DVD picture quality.
Although 1.60 brings the ability to mute PS4 camera's microphone, I have to say I'm disappointed with the 1.60 update as I was expecting much more features and enhancements to be added especially with DVD playback, I couldn't notice what exactly has been improved in terms of DVD playback picture quality and my PS3's DVD playback picture quality is still way better than PS4, I guess that might be related to PS3 noise reduction control which is still missing from PS4 DVD playback. I am sure that PS4 can do noise reduction way better than PS3 since it has almost 10X more powerful hardware, but the problem is with the playback software which is still inferior to the PS3 for some unknown reason. One might argue that PS4 was designed to play games not to be a multimedia hub and you can watch DVDs on other devices, but if last gen consoles were more than capable of both games and media playback, this gen has to be better in everything including such additional functions.
Meanwhile I guess I will have to wait for the next update, which will hopefully add more media playback functionality to the PS4 and make it as great as PS3 once was.