It is advisable to put your first subtitle at least 4 seconds after the start of the DCP to make sure it is seen Message

[chrusli]

Dear DCP-o-matic team

While doing a VF with subtitles, I encounter this message when I want to start the "Make DCP" job "It is advisable to put your first subtitle at least 4 seconds after the start of the DCP to make sure it is seen."

DCP o matic It is advisable to put your first subtitle at least 4 seconds after the start of the DCP to make sure it is seen.jpg

I don't understand why it is saying that. What I did:
- Load DCP
- Load subtitle
- Changed "Video fram rate that content was prepared for" to 23.976
- Trim from start to 18 frames

What does this message mean? Thank you for the help in advance.

Best regards
Stephan

[carl]

It means that you have a subtitle which starts near the beginning of your DCP (within the first 4 seconds). SMPTE Bv2.1 says that some playback systems may have problems with this, so it suggests that you move it later.

[chrusli]

Okay. This error message is referring to the first text element of the subtitle. That's what confused me. Am I correct in my assumption, that this will possibly just not display subtitles that are within the first 4 seconds, but will not have effects on subtitles that appear later or even on the timing?

Am I also correct, that the solution to the problem is to change the timing of the position of the DCP to 4 seconds? I tested it, and this seems to do the trick. The Video is delayed by 4 seconds. What irritates me, though, is that the play length can't be adjusted to +4 seconds, and it doesn't show that the film now lasts 4 seconds longer in the play length.

DCP o matic It is advisable to put your first subtitle at least 4 seconds after the start of the DCP to make sure it is seen 2.jpg

DCP o matic It is advisable to put your first subtitle at least 4 seconds after the start of the DCP to make sure it is seen 3.jpg

Thank you for your great support!

[chrusli]

I'll just answer parts of my questions myself, because it is clearly stated in your manual, https://dcpomatic.com/manual/html/ch06s07.html. Play length only changes if trims are applied.

I'm looking forward to your feedback on the other questions.

[Carsten]

The playback behaviour of various DCI equipment unfortunately is not well documented. A lot of production companies dealing with DCP mastering learnt limitations of equipment in the field the hard way, and most of these experiences went into SMPTE Bv2.1. It is possible that only a single outdated server is having these problems, but, you are still advised to follow that recommendation. We have seen all sorts of things happening with subtitles, and it wouldn't surprise me if a specific subtitle engine does not only miss the first subtitle <4s, but crashes completely and then does not show any subtitle at all.

The easiest way if you have your first subtitle at a sub 4s position is to just create a start position offset for video/audio and subtitle file in DCP-o-matic. The worst outcome would be 4s of black and silence before the actual movie starts.

Yes, play length is a source footage parameter, a start position offset does not change the source content play length. What does change is DCP play length.

[chrusli]

Thank you Carl and Carsten for clarifying. It's great that DCP-o-matic and your immense knowledge helps us avoid those mistakes. Your software is great and so is your support. I hope you guys feel like the rockstars you are! ✌