The question here seems to be whether these are single layer or double layer BDRs. Single layer is generally 25gb while double layer is 50gb.
I expect the time estimate has to do with how aggressively these video files have been compressed. More compression saves space at the expense of quality.
If these are true 4k video files, I can't imagine how one could get much time on a single layer BDR. Keep in mind that commercially made 4kUHD titles are generally pressed onto 66gb or 100gb media.
Rich86
1. The discs are double layered. Hence the 45,1GB capacity.
2. 4K UHD Videos are cartoons with less colours than for example Avengers.
I want to keep ~23Mbps bitrate for each of the episode (I figured out it's the best value and size wise it just fits).