View Bug Details

IDProjectCategoryView StatusLast Update
0002919DCP-o-maticBugspublic2024-12-22 01:26
Reportercarl Assigned Tocarl  
PrioritynormalSeverityminorReproducibilityalways
Status confirmedResolutionopen 
Summary0002919: PE at reel_writer.cc:534 creating 18fps DCP
Description

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Tagsemail, git
Brancharbitrary-hz higher-hz
Estimated weeks required
Estimated work requiredMajor

Activities

carl

2024-12-21 23:12

administrator   ~0006654

Seems to be because we're tring to add one video frame to a DCPTime and this isn't integer at 18fps. The two branches try to increase the timebase, or use a custom timebase per DCPTime. Both seem quite involved.

carl

2024-12-21 23:12

administrator   ~0006655

OP says 18fps is allowed in for DCPs but I can't find anything to suggest that.

mhm

2024-12-22 00:30

reporter   ~0006656

SMPTE ST 428-21 specifies 200/11 ~ 18.18 fps

(ST 428-21:2011, Archive Frame Rates for D-Cinema, https://doi.org/10.5594/SMPTE.ST428-21.2011)

mhm

2024-12-22 00:30

reporter   ~0006657

I am not aware of any hardware support for this though.. maybe that has changed?

carl

2024-12-22 00:36

administrator   ~0006658

What does "archive" mean here? Is any actual installed system supposed to play 200/11 DCPs?

mhm

2024-12-22 01:12

reporter   ~0006659

It refers to films held in film archives, or rather digital restorations of those films.

Silent films are often made to be projected in frame rates below 24 fps. 16 and 18 fps are the most common.

mhm

2024-12-22 01:26

reporter   ~0006660

And yes, I believe that systems are supposed to play these DCP:s. Yet there seems like very few manufacturer have bothered to implement it..

CineAsset Mastering Suite seems to have implemented support in 2014: https://www.dcinematoday.com/dc/pr?newsID=3554

There is some discussion about this in the Journal of Film Preservation, issue 0000104, April 2021 (page 32): https://www.calameo.com/fiaf/books/000918540dc6cb729643b

Bug History

Date Modified Username Field Change
2024-12-18 16:38 carl New Bug
2024-12-18 16:38 carl Tag Attached: email
2024-12-18 16:38 carl Tag Attached: git
2024-12-18 16:39 carl Assigned To => carl
2024-12-18 16:39 carl Status new => confirmed
2024-12-21 23:10 carl Branch => arbitrary-hz higher-hz
2024-12-21 23:10 carl Estimated work required => Medium
2024-12-21 23:12 carl Note Added: 0006654
2024-12-21 23:12 carl Priority high => normal
2024-12-21 23:12 carl Severity major => minor
2024-12-21 23:12 carl Note Added: 0006655
2024-12-21 23:13 carl Estimated work required Medium => Major
2024-12-22 00:30 mhm Note Added: 0006656
2024-12-22 00:30 mhm File Added: Screenshot 2024-12-22 at 01.26.48.jpg
2024-12-22 00:30 mhm File Added: Screenshot 2024-12-22 at 01.27.04.jpg
2024-12-22 00:30 mhm Note Added: 0006657
2024-12-22 00:36 carl Note Added: 0006658
2024-12-22 01:12 mhm Note Added: 0006659
2024-12-22 01:26 mhm Note Added: 0006660
2024-12-22 01:26 mhm File Added: Screenshot 2024-12-22 at 02.23.04.jpg
2024-12-22 01:26 mhm File Added: Screenshot 2024-12-22 at 02.23.29.jpg