Which Errors & Warnings are dealbreakers versus FYIs

[SethMutchler]

Hi DOM friends!

I manage DCP delivery and QC for our theater. I've started in DOM Player verifying DCPs delivered by distributors (when they are unencrypted and not from Deluxe) to enhance my QC efforts. I get the occasional errors, SMPTE Bv2.1 errors, and warnings. Most of them I can read and understand if they're a "not best practice but acceptable" such as non-standard frame rate, too many characters in CCAP line, or lack of FFEC/FFMC markers.

Fortunately, I have not come across any yet that are clearly "this DCP is broken and needs to be returned to the distributor" (such as hash mismatches). However, there are some that I have gotten (and others that are listed in Chapter 19 of the manual) that are ambiguous to me - is this an acceptable error, or is a QC-failing error?

My immediate question is, would anybody be kind enough to give me the thumbs up or down in proceeding with the below errors/warnings (not all from the same DCP), and then also would it be possible to create some annotation to Chapter 19 with explanation/implication of errors & warnings? I'd be more than happy to help with that effort, but as I have described, I don't know enough to tackle it solo.

My error list:

Errors:

• A subtitle lasts longer than the reel it is in.

• <MainSoundConfiguration> describes incorrect number of channels (MainSoundConfiguration has 8 channels but sound assets have 16)

SMPTE Bv2.1 errors:

• Subtitle asset df155e13-5ee2-41b9-b2fd-0ad0d6dd27e4 has a non-zero <EntryPoint>.

• A 4K JPEG2000 frame has 1 guard bits instead of 2.

• The XML in the closed caption asset [asset]_sub.mxf takes up 624158 bytes which is over the 256KB limit.

Warnings:

• Frame [#] (timecode xx:xx:xx:xx) in asset [CPL]-video.mxf has an instantaneous bit rate that is close to the limit of 250Mbit/s.

• More frames (not listed) have an instantaneous bit rate that is close to the limit of 250Mbit/s.
  (I presume this is fine since an error would be thrown if it exceeded 250, but thought I'd double check)

• The CPL [CPL] has no CPL metadata tag.

Many many thanks!

[Carsten]

As far as I know, none of these are dealbreakers. Different types of cinema servers and projectors support a wide range of ambiguous DCP parameters without choking.

- Carsten

[SethMutchler]

Thanks Carsten! Always appreciate your knowledge in this forum

This might then be a good segue into a discussion of a working group on an annotated Chapter 19 of the manual, especially if that's work that Carl would find helpful. But even as an unofficial document, I know I would find value in it so possibly others would as well.

I have a colleague who may be interested, if anybody else would want to collaborate on that!

[carl]

I'm happy to receive any corrections / clarifications / additions to the manual!

It would be nice to segregate errors/warnings better, but it is rather challenging given the mixture of:

• Errors that we have seen first-hand causing actual projection problems in common equipment
• Errors that cause actual problems in equipment which is rarer (taken as a worldwide percentage) but very common in certain regions.
• Errors that other tools flag, meaning that people get their DCPs refused, which in that case is a dealbreaker even if there's no evidence of problems caused by the "error"
• Errors that come out of some haze of heresay/rumour "it used to cause problems" / "the DCP didn't play and I changed X, Y and Z to fix it and I think it was Z that actually fixed it."

I realise that the current situation is confusing and welcome any improvements...

[SethMutchler]

Hey Carl, thanks! I hope there wasn't any offense taken, INCREDIBLY grateful for your work. The manual as-is is already so helpful, and having the ability to verify DCPs is exceptional.

I see the challenges you lay out here, definitely makes it not open-and-shut. I can see how it would easily be dependent on the DCP and the equipment at hand.

I might work on an annotation project myself in my spare time. I got the skeleton created, and will update as my schedule allows, and as I see errors and warnings appear in my own work. Might stagnate for periods of time, but it'll be a fun and useful project (and a good distraction!)

If others wish to monitor this, or contribute, that is welcome.

https://docs.google.com/spreadsheets/d/ ... sp=sharing

Thanks

[carl]

No offence taken at all, it's a tricky topic but all assistance is most welcome!

Other tools have frustrated me in the past by giving cryptic errors with no useful detail, and I'm keen that DCP-o-matic avoids the same problem.