captions, what is VF?

[funkytwig]

Bwwn looking at https://dcpomatic.com/manual/html/ch06s06.html and I think I am missing something. Read something about *_VF files but dont quite get it. Do I have one package for the main DCP and another for closed captions? Ime confused.

Also, is 'Separate subtitles' just a different name for closed captions?

I tried adding srt file & setting it to Closed Captions and making DCP. When I loaded the *_OV into the player under View->Closed captions it just said Track Unknown()

[carl]

The page you linked is talking mostly about subtitles, the "burnt-in" vs "separate" part is just referring to how you can put subtitles directly into the image, or include them a DCP to be overlaid on projection.

VF is perhaps better explained here. The OV ("original version") and VF ("version file") stuff is just a way of making one DCP refer to another. The classic example of this is with subtitles, for which the common approach is to have an OV containing picture and sound and several VFs containing subtitles.

The Track "Unknown()" thing is just because you didn't add a closed caption "track" with the "CCAP track" drop-down when making the DCP. This is a bit confusing and the interface could probably be improved here. With CCAPs you can have multiple versions which the user (I think) can choose between on whatever device they are using to view the CCAPs.

If you play your test DCP you should still see the closed captions appearing in the player's closed captions window.

[funkytwig]

Thanks for taking the time to reply.

OK, so I make 2 DCPs with 2 DCP projects, the original one and a VF one. Looked through the instructions, and much better.

In the 2nd one, I use 'Add DCP...' and also add the srt file and select the options mentioned in the instructions you just linked to?

So what could the name of the second one be if the first one was
TestJ_TST-1_F-178_EN-EN_20_2K_20230503_FUN_SMPTE_OV?
is it TestJ_TST-1_F-178_EN-EN_20_2K_20230503_FUN_SMPTE_VF?

I could call the second project Testj_EN_VF, guess it does not really matter.

I then put them both on the drive and the projectionist chooses. If they do not want subs they chose the OV and if they want them they chose VF.

I guess if you want multiple languages you have multiple projects with EN-EN changes. Is the first EN the audio language and the second the sub language?

Am I correct in thinking with the Closed Caption you do not get to say size, position, Font etc? Options seemed to be greyed out.

OK, just tried it. Made first DCP and imported it and the srt. 'Use's this DCP's ... as OV and make VF' is grayed out .

Thanks again, Ben

PS When I crack this I will write it up and publish it. I would be up for contributing this to the official manual.

[carl]

In the 2nd one, I use 'Add DCP...' and also add the srt file and select the options mentioned in the instructions you just linked to?

Right

TestJ_TST-1_F-178_EN-EN_20_2K_20230503_FUN_SMPTE_OV?
is it TestJ_TST-1_F-178_EN-EN_20_2K_20230503_FUN_SMPTE_VF?

I could call the second project Testj_EN_VF, guess it does not really matter.

Normal practice would be to call the first one EN-XX (i.e. english soundtrack, no subtitles) and the second EN-EN (i.e. english soundtrack, english subtitles) - see the naming convention. DCP-o-matic will do this for you if you set the subtitle language in the DCP-o-matic interface.

Am I correct in thinking with the Closed Caption you do not get to say size, position, Font etc? Options seemed to be greyed out.

Right, some devices used to display closed captions do not support multiple fonts etc. (e.g. they are dot matrix displays).

OK, just tried it. Made first DCP and imported it and the srt. 'Use's this DCP's ... as OV and make VF' is grayed out

In that case there should be a clue under the greyed-out button which explains what you need to do to make it possible. Is there something there?

[funkytwig]

OK, I figured it out, I need to click on the .DCP file in the Contents window to be able to click the checkbox.

"Right, some devices used to display closed captions do not support multiple fonts etc. (e.g. they are dot matrix displays)."

And some have subtitles added at the bottom of the projected image or is the only way to do this to burn them in?

[carl]

And some have subtitles added at the bottom of the projected image or is the only way to do this to burn them in?

I'm sorry, I don't follow this question, can you rephrase it?

[funkytwig]

Maybe I'm misunderstanding what closed captions are. My understanding is the VF package has the subtitles (or should I say the closed) in them and the projectionit can 'load' this package as well as the OV package and project the film with the subtitles overlayed at the bottom of the video like VLC does). Basicaly it comes out like burnt in subtitles when projected?

So this can be used to add Spanish subtitles over the picture if you were, for example, playing an English language film in Spain. Having multiple VF packages would enable you to distibute the same OV file and diferent VF files depending on the language of the place you were sending the film?

[carl]

With DCP there are two ways to present "timed text" (i.e. some text that accompanies the film) to a viewer.

With open subtitles, the text is put on the screen so that everybody can see it (i.e. it's "open").

With closed captions, the text is put on some device that only some people can see. This might be a small screen stuck into the cup holder of their seat, or some arrangement with mirrors and a screen at the back of the theater, or whatever. But definitely not on the same screen as the film's image. This is a fair bit more complicated but has the advantage that those who don't want to see the subtitles don't have to.

If you make a OV (with no subtitles) and a VF where you add some srt file, set it to be used as "open subtitles", then project the VF, the subtitles will appear on screen as if they had been burnt into the image, like you say.

[funkytwig]

OK, got it. I just figured it out. Thanks.

Been looking for guidelines for subtitles but cant quite find them.

So far I have a maximum of 2 lines and it seems no more than 42 chars a line, which seems quite small.

I guess there are also guidelines for how long they are up for and I gather I need to leave 2 frames between each subtitle.

[carl]

The best guidelines for DCP subs are probably in the SMPTE Bv2.1 application profile:

• First subtitle at least 4 seconds into the DCP.
• Minimum duration 15 frames, with at least 2 frames between each subtitle.
• Aim for a maximum of 52 characters per line, and don't go over 79. No more than 3 lines.