You new smartphone will only record up to 5 minutes of 4K video
All the high-end Android smartphones released in the last six months or so have the ability to record videos in 4K resolution. Considering that 4K content and display are still a rarity, having this feature on your $800 smartphone is a biggie.
As it turns out though, there is a slight catch. None of them can record 4K videos at a stretch for more than 5 mins. This includes the Xperia Z2 and the Galaxy S5 as well as last year’s Galaxy Note 3.
The reason behind this is that the Snapdragon 801 chip found inside these devices does not feature a hardware based HVEC decoder or encoder. This means that all the heavy lifting while recording videos has to be done by the CPU itself, which puts them under heavy load. In turn, this leads to them overheating within a few minutes of use, leading the phone to shut down the camera app to prevent the CPU from frying itself.
As an Xperia Z2 owner, I can personally confirm this problem. The device heats up extremely quickly while recording 4K videos with the part near the camera being too hot to even touch. The phone will then automatically close the camera app and reduce the display brightness to lower the internal temperatures.
At the moment, there is no solution to this problem. If you want to record 4K videos for more than 5 minutes, make use of the IP ratings of the Galaxy S5 and Xperia Z2 and drop them in a bowl of water to make sure they remain cool while recording the video.