By default, the camera records video in Ultra HD resolution at 30 frames per second, but the user can always select 60 frames / s. The latter option allows you to create videos in high resolution and a high frame rate, so video files take up a lot of space in the phone’s memory. For this reason, the camera on both devices has limitations. It’s about the 5-minute rule. For various reasons, manufacturers of Android-devices limit the time of recording video at the highest settings. Most often this is done because of the memory and processing power of the mobile gadget. Previously, Samsung forbade its flagships to record 4K-video at 30 frames per second for more than 5 minutes, and now the same thing happens only with a combination of 4K and 60 frames / s.
Samsung Galaxy S9 4K Video Recording