Film-Tech Forum ARCHIVE: DCI Bit Rate Increase?

This is topic DCI Bit Rate Increase? in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Lyle Romer (Member # 1266) on 06-22-2012, 09:35 AM:

I was reading an article about 4k resolution and issues getting it to the home (which is a good thing). In the article, the author mentions that the current DCI maximum bit rate is 250 Mb/s but that it is expected to increase to 500 Mb/s over the next 5 years. Is this true?

Posted by Carsten Kurz (Member # 5396) on 06-22-2012, 10:04 AM:

Currently, DCI bitrate is limited to 250MBit/s. This is the same for 2k/2D, 2k/3D, and 4k/2D. The Wavelet compression scales especially well with higher resolution, so 4k does not really need increased bitrates. Also, there is still not a single feature that used up the max bandwith so far, not even high-end 3D features. Most CPLs max out around 130-160MBit/s. So there is quite some headroom left.

Different thing for HFR - High Frame Rate features. The frame rate at least doubles over 2k/3D/24fps, so they are going for higher datarates with HFR. Current HFR capable media blocks quote 400-500MBit/s throughput. Qube even boasts 1000MBit/s storage throughput (two dual-IMB).

So yes, the DCI specs will change/adopt with HFR. But for backwards compatility, 2D/2k, 2D/4k and 3D/2k will still stay with the 250MBit/s limit. Not every DCI system in the wild will or can be upgraded to HFR, they will stick with the 250MBit/s limit and would crash on CPLs with significantly higher datarates.

- Carsten