Emerging SMPTE standard for D Cinema image masters

[boxerab]

Plan to use lossless JPEG 2000 compression for image masters instead of TIFF


https://github.com/SMPTE/st428-24

https://github.com/SMPTE/st428-24/blob/ ... 0Image.pdf

Unfortunately this will make encoding slower (!)

[IoannisSyrogiannis]

I don't know about that (if and how much), but it will nearly half the storage needed.
So, even though I am a person that uses DCDM once in a blue moon and might never use a pDCDM, I like the idea.

[boxerab]

The new standard uses new Part 15 JPEG 2000 for compression, so even though it is faster than original Part 1,
it is not compatible with current DCI standard, so each image must be decompressed, then re-compressed with
lossy Part 1. This is going to add maybe 50% more time to encode, depending on which implementation is used
to do the transcoding.

[Carsten]

As this is targeted only at masters, I don't see any impact for anything targeted towards cinema presentation. DCI servers were never able to play TIFF DCDM in the past as well. At some point in time, it will certainly be useful if DCP-o-matic is able to READ this lossless J2K master format in order to create distribution DCPs. Due to FFMPEG/libav, the decoding performance for source video formats is all over the place anyway. For the TIFF image series, IO throughput is probably more of a limiting factor, so, using a lossless J2K may actually even improve encoding time because of a smaller input/source file bandwidth.



- Carsten