Creating a DCP from a BluRay

[bojtalepenye]

Hi there,

I'm new to Digital Cinema Packages (DCPs) and considering converting a BluRay.x265.10bit.SDR film to a DCP. The film has a resolution of 3840x1632, 7.1 English DTS-HD Master Audio at 17681 kbps bitrate.

Bitrate Conversion:
How would DCP-o-matic handle converting the film's 17681 kbps bitrate to 150 Mbit/s for DCP?

JPEG2000 vs. MPEG 16-235:
Would using JPEG2000 instead of MPEG 16-235 cause any quality loss?

DCP Specifications:
The film's 3840x1632 resolution suggests a 4K DCP scope with 2.39:1 aspect ratio.
Since it's SDR, should I use Rec.709 for color space? I read that letting DCP-o-matic treat rec709 as p3 wouldn't work.

Audio:
Can I retain 7.1 audio in the DCP?

Could a DCP package like this be as good as those that are played in cinemas? Or would I lose data during the process? In general, do DCPs lose data when they are first compressed into an HEVC 265 BlueRay disc and then converted back into DCPs?

Huge thanks for anyone who clears this for me

[Kewl]

I'm my experience, the limiting factor with Blu-rays is the source. Rip the blu-ray with MakeMKV, bring the resulting file in DCP-o-matic, and go on from there.

[Carsten]

The Bluray has less quality than a well mastered DCP from 10-12Bit P3 masters. However, you will hardly notice the difference for mainstream Blurays.

As to your other questions - use MakeMKV to capture the original Bluray video and audio stream, and convert the MKV directly in DCP-o-matic. Most settings will fit automatically. You will need to crop the black bars from the letter-boxed UHD scope image in order to fit the image into a scope DCP container properly.

HOWEVER - as you mention 4k resolution, the Bluray is most likely an UHD - and the color conversion may not be optimal. In that case, I would prefer to convert the standard 1080p Bluray of the same title. The resolution loss is usually less visible than the lack of proper UHD/rec.2020 color conversion.

Not all UHD discs however, use HDR color encoding, so you may be lucky using the standard rec.2020 conversion preset.


Full JPEG2000 0-255 vs. Video MPEG 16-235 - you shouldn't touch that setting. For standard video file conversion, DCP-o-matic will automatically select the 16-235 option, which is right.


7.1 dts HDMaster Audio can be converted into a standard 7.1 DCP. Is this only for a screening in your own cinema, or will it be screened in other cinemas as well?

[bojtalepenye]

No, this won't be screened in any public cinemas in the near future, however, it will be part of an exclusive viewing experience in my private movie theater soon. But that is besides the point.

The good thing is, that this is not actually encoded in HDR. I tried converting 3840x2160 4K UHD HDR BlueRays in the past and that didn't go as planned.
Since this is an SDR could I technically use the rec.2020 conversion preset?

And one more question: You said, I shouldn't touch the setting that determines whether DCP-o-matic uses JPEG2000 or MPEG 16-235. Why is that? And when would DCP-o-matic use JPEG2000?

Thank you,

[Kewl]

Since it's SDR, it will be limited range at 16-235 with Rec.709 color space. The JPEG2000 codec is not directly related to the SDR specs.

[Carsten]

That setting only uses 'JPEG2000' and 'MPEG' as examples for the colour range. e.g. you would use 0-255 for JPEG2000 source material, and 16-235 for classic video source material. The DCP created will always use 12Bit 'full range' X'Y'Z' encoded JPEG2000.

You may also use the 0-255 setting for e.g. full range RGB TIFF just as well, and the 16-235 option for MP4/h.264, or most other video formats.

Only very few video formats use full range 0-255 signals.

I guess an SDR UHD should convert properly with the rec.2020 or rec.709 setting.

The only UHD disk I ever tried to convert used HDR, and that didn't work out as expected, so I used the standard Bluray from the same 4k master.

- Carsten

[bojtalepenye]

Oh, that clears it form me, thank you!

So there won't be any visible quality loss and even if the MPEG 16-235 option is selected the created DCP will use the X'Y'Z' JPEG2000 encoding format.