View Single Post
Old 02-13-2016, 10:19 PM   #38
pedromvu pedromvu is offline
Blu-ray Guru
pedromvu's Avatar
Nov 2010

Ok here is a breakdown based on that Lawrence of Arabia UHD size assuming it is using AVC 264 compared to the blu-ray.

BD feature size (includes audio): 42.15GB
BD Video bitrate: 22.25Mbps size: 37GB
BD Combined audio bitrate: 4.2Mbps size: 6.98GB (not sure why I get a discrepancy here, audio + video ends up being bigger than feature size by about 1GB, no problem this is worst case scenario)
Total bitrate: 26.45Mbps


UHD Download size (including audio): 111.3GB

Assuming the same audio sources as BD, video size should be around 111.3GB - 6.98GB = 104.3GB
UHD video size compared to BD = 2.82x the size

Assuming worst case scenario using H.265 should use about 60% of H.264:

H.265 Video size = 62.58GB bitrate = 37.64Mbps

Adding worst case scenerio of 2.5Mbps for HDR:
H.265 with HDR bitrate = 40.14Mbps size = 66.74GB

Assuming 20% overhead for main track for Atmos:

UHD combined audio bitrate: 4.62Mbps
UHD total bitrate: 44.76Mbps
UHD feature size: 74.42GB

Conclusion: this is of course just a mere approximation, and one thing I didn't considered is that besides HDR, the size could be a bit bigger because of the use of 10bit color but that is hard to estimate because of the compression and I don't know if it is already considered when comparing H.265 to H.264, but since I used most worst case scenarios I doubt the end result could be bigger.

Also this shows it would be perfectly acceptable for UHD movies to have an average video bitrate of 40Mbps since Lawrence of Arabia is considered to have reference video quality on blu-ray to begin with.

Finally I think this also means that for very long movies like this, it would be hard to fit in 66GB discs, but most other 1:30 to 2:30 hour movies would be fine, depending on supplements.

Last edited by pedromvu; 02-14-2016 at 04:17 AM.
  Reply With Quote
Thanks given by:
bruceames (02-13-2016), lemonski (02-14-2016)