Subtitles too small in cinema

[Dusk]

Hello, I have created a dcp with an englisch subtile - after testing it in the cinema, the font is much smaller than in the preview of dcpomatic. I also testet it with several dcpplayers - the font ist always normal and perfect. Any idea why the font is smaller in the cinema?

Next question: I want to create DCP with the possiblity to turn off the subtitle. After creating a DCP with dcpomatic with a subtitle (not burned in), it is not possible to turn it off. How to create a DCP with one subtitle to disable?

[Carsten]

Disabling subtitles is not a feature of DCI cinema. The usual way to do this is to supply a normal, and a subtitled version, and the projectionist/operator decides which one to play. There is no checkbox or button on a DCI server to disable subtitles during a playout operation.

Some servers have configuration options to disable subtitles, but they are hidden in server setup options, these are not accessible to normal operators/projectionists. As such, they are not meant to be used on a per-feature basis.

As a subtitle-VF is usually very small and can be compressed to just a few kBytes, it's not really an issue. Also, projectionists/operators are used to finding two versions for NonSubbed/Subbed on their distribution media and act accordingly.

- Carsten

[carl]

It seems there is uncertainty in the sizing of DoM preview subs:

https://dcpomatic.com/mantis/view.php?id=1251

It's on the list for investigation... feel free to add comments there about what you are seeing.

[Carsten]

I'm wondering if all servers/projectors display subs in the same relative size? The Doremis have an option to switch from projector-rendered to server-rendered subs. The Doremi server subtitle engine has options to shift and resize subs. Projectors do not.

- Carsten

[Dusk]

What I noticed because of the subtitle: If you burn the subtitles into the movie, they will be shown exactly the same in the cinema, as in the preview of Dcpomatic. However, as soon as you put the subtitles on switchable or if they are not burned in, then these are too small in the cinema and the line spacing is no longer consistent.

For this reason, the function with switchable subtitles is currently not usable for me - did I understand correctly that this is a bug of dcpomatic?

[Carsten]

No, it's not a bug, it is simply not intended to switch off subtitles for a presentation in cinema. It's not a feature of the DCP, but of the cinema servers/projectors. They don't support disabling subtitles. It doesn't work as on DVD/Bluray Players or Netflix where you can switch languages and title tracks at will.

If you are concerned about the size of the timed-text subtitles, why don't you burn in? In both cases, timed-text or burn-in, you have to supply separate DCPs - one without subs, one with subs. In the case of timed-text subs, that could be a VF and smaller, but other than that...


- Carsten

[Dusk]

That was not the question of my last post. Logically, you can burn the subtitles - but what if I want to create a DCP with several subtitles - for me it is a bug if the burned subtitles are displayed correctly, but the switchable or selectable are too small in the cinema. I would like to know the reason or a tip why and how to fix that!

[Carsten]

Of course, but as I said, timed-text subtitles are rendered by the cinema equipment, not DCP-o-matic. So, first we need to find out why this happens. And of course, for now, you may simply set the fonts larger. It may be that DCP-o-matic preview and player render font sizes not according to the subtitling spec, which is:

----
Used to specify the size of the font. Size is given in points. Fonts are rendered as if the screen height is 11 inches, so a 72pt font would be 1/11 screen height.
----

I guess I'll try that on our two projectors of different make to see what comes out. How much of a difference do you see?

Can you inquire at the cinema about the type of server and projector?

...so, I created four test DCPs for testing on our Sony and Barco. Let's see...

- Carsten

[Carsten]

After my todays tests, I can at least confirm that there is no general problem with subtitle sizes.

I created test slides with ARIAL.TTF, both burnt-in and timed text, on the same 'canvas', with identical parameters, and they come out exactly same size and shape on both our Sony and Barco DLP projector. I also created one version that has a long sentence with a grey font surrounded by a yellow outline, both in timed text, and burnt-in just a line below. On the Sony, it was 'frightening' how close both subtitle lines looked, in size, shape, and color rendering of both the grey and yellow. You couldn't tell a difference. On the Barco, there was a color difference, but no size difference. I also noticed that the timed-text version left the screen a fraction of a second later, just barely noticeable.

The grey/yellow outline version also had fade-in/fade-out times associated with both the burnt-in as well as timed-test version. Naturally, that fade curve was slightly different for burnt-in and timed-text.

All test files show the same behaviour in DCP-o-matic standalone player (2.13.16).

If you want to test yourself, here are the test DCPs (54MBytes): https://www.dropbox.com/s/vyujqgaxyb0tg ... F.zip?dl=0

I did not test all possible appearance properties for this basic test, but I wanted to see wether source (SRT/XML) and container/size reference (Flat/Scope) makes a difference.

Dusk - can you test these in your cinema, and/or can you supply the subtitle file to me showed differences in your cinema? Can you inquire the type of server/projector?

- Carsten

[Mark]

Hi Carl, Carsten,

Dom version = 2.14.36

I noticed a Y plane placement change while using an .OTF font.

I switched dcp format from HD to Flat (1998 × 1080) and the subs shifted to screen bottom, even though the Y ratio is the same.

I closed and re-opened the flat project
- subs were now at the same height from bottom on Flat and HD projects.
Burnt in exports were correct height.

It could be a refresh issue?
Impact:
Incorrect heights shown on DOM monitor after changing formats.
Incorrect adjustments made as a result.
To test:
incorrect export as VF ? As burnt in?

Current solution:
Close project and re-open.
Burnt in heights match.
VF heights not tested.

Best,

Mark