Film-Tech Forum ARCHIVE: 4K BRays for commercial cinema playback

This is topic 4K BRays for commercial cinema playback in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Frank Angel (Member # 248) on 05-01-2016, 12:49 AM:

Has anyone had any experience using the new 4D BRays with a DCI projector? The color gamut wouldn't be as good, but just from a subjective visual assessment -- how does it look? I have seen regular BRs feed into a cinema projector and that lower quality is apparent (but not egregiously so that an audience would complain). I am very curious as to what a picture derived from the 4K discs looks like on a theatre screen.

Posted by Steve Guttag (Member # 268) on 05-01-2016, 09:13 PM:

One needs a new UltraHD player but furthermore, one needs an HDMI 2.0a system...which I don't think any DCinema system currently has. I don't even think the Barco Alchemy has gone beyond HDMI 1.4 but it is currently the most likely candidate to handle HDMI 2.0a and can handle 4K/60 in 2D mode...all ICP based projectors are limited to 4K/30.

Posted by Leo Enticknap (Member # 534) on 05-02-2016, 12:08 AM:

Presumably the new 4K BDs are limited to the same 25GB (single layer) or 50GB (double) bandwidth limit as their 1080p predecessors. So the bitrate will be roughly the same, and if it's spread more thinly to encode more pixels, the video stream will be more aggressively compressed. So I'd be surprised if, subjectively, they'd look any better.

Posted by Daniel Schulz (Member # 1881) on 05-02-2016, 01:24 AM:

quote: Leo Enticknap
Presumably the new 4K BDs are limited to the same 25GB (single layer) or 50GB (double) bandwidth limit as their 1080p predecessors. So the bitrate will be roughly the same, and if it's spread more thinly to encode more pixels, the video stream will be more aggressively compressed. So I'd be surprised if, subjectively, they'd look any better.

The disc capacity and bitrate are greatly increased over Blu Ray, plus UHD Blu Ray is using a more efficient video compression codec in HEVC (h.265). That, combined with support for expanded color space and HDR should make it a noticeable improvement over Blu Ray.

Posted by Marco Giustini (Member # 4544) on 05-02-2016, 04:54 AM:

New UHD Blu Ray's are up to 100GB. They also should have REC 2020 as gamut. Only main drawback is colour sample, only 4:2:0 I believe.
The AP20 is now shipped with an HDCP 2.2 (and 4K capable) HDMI board I reckon? Still, you need the projector to be HDCP 2.2.