It'll make the playback easier for your phone.

So if you want to transfer the video to your phone to watch the movie, it's suggested that you convert the MKV video to MP4 in a lower resolution.

But 4K MKV might not be suitable for playback on mobile devices as they might not be powerful enough to process such a high-definition video. You can use third-party video players like VLC, Leawo Blu-ray Player to play the 4K MKV video. To rip Blu-ray MakeMKV is one of the best options you can have. Hit the MakeMKV button on the right to let MakeMKV start ripping the 4K Blu-ray movie to lossless MKV. Set where you'd like to save the MKV video in in the output directory box on the right side. All the selected content will be saved to the MKV video. On the left side of MakeMKV's interface, Check the box in front of the content you need to select them. Click on the optical drive icon that appears after the program detects the 4K Blu-ray disc to allow MakeMKV to load the content in the disc to the program. Insert the 4K Blu-ray disc into your Blu-ray drive and then kick off MakeMKV. Download MakeMKV from online and install it on your computer. Here's how to rip 4k Blu-ray with MakeMKV With MakeMKV 4K Blu-ray can be easily processed. As there'll be no quality loss during the conversion, not only the image, but also the audio quality would be just as good as playing the original Blu-ray. If you have a 4K monitor, you can use MakeMKV to rip a 4K Blu-ray to your computer and make the best out of the 4K MKV video. MakeMKV is capable of processing most Blu-ray/DVDs, including 4K and 3D Blu-rays. How to use MakeMKV to rip 4K Blu-ray to lossless MKV

Makemkv 4k blu ray ripping time