.ASS subtitles

Anything and everything to do with DCP-o-matic.
Ron
Posts: 44
Joined: Thu May 26, 2022 3:09 pm

.ASS subtitles

Post by Ron »

I imported subtitles from an .ASS file to create a "VF DCP" and noticed several things:

- Font type is ignored and DoM's default font is displayed instead
- Positioning is not read accurately since it's in point size and DoM doesn't seem to have any controls for that.
(also positioning for indivual subtitles which is different from all other subtitles)
- 2-line subtitles show with very wide line spacing which need to be ajusted
- Font size is ignored because point size doesn't translate to the large cinema screen
- After making size adjustments within DoM font looks larger on DoM's playback than on Preview

- Text seems to be the only thing that DoM imports from an ASS file.

Addendum:
Since ASS formats are not read by DoM there is no point in using .ASS over SRT if your goal was to import typeface & formatting information.
Last edited by Ron on Sun May 29, 2022 8:44 pm, edited 5 times in total.
carl
Site Admin
Posts: 2338
Joined: Thu Nov 14, 2013 2:53 pm

Re: .ASS subtitles

Post by carl »

Perhaps you could attach the .ass file you are using, or send it to carl@dcpomatic.com
carl
Site Admin
Posts: 2338
Joined: Thu Nov 14, 2013 2:53 pm

Re: .ASS subtitles

Post by carl »

Thanks for sending the .ASS file.
- Font type is ignored and DoM's default font is displayed instead
That is a bug that should be fixed in 2.16.14, whenever it's ready (provided the font name in the ASS file is available on your system).
Positioning is not read accurately
Can you give some more details about what you mean here? Are you talking about the margin settings? In the file you sent I can't see any specific positioning.
2-line subtitles show with very wide line spacing which need to be ajusted
DoM assumes that the line spacing should be 1.2 times the font size. Perhaps that is too much? What line spacing do you set in DoM to get a pleasing result?
Font size is ignored because point size doesn't translate to the large cinema screen
Font size is respected when I try it - DoM assumes that the cinema screen is 792 points (i.e. 11 inches) high (as with the DCP spec) so that a 72 point font will take up 1/11 of the screen height - are you expecting something else? If you change the font size in the .ASS does the subtitle not change in DoM?
After making size adjustments within DoM font looks larger on DoM's playback than on Preview
I will take a look at that now and see if I can reproduce it.

Regards,
Carl
carl
Site Admin
Posts: 2338
Joined: Thu Nov 14, 2013 2:53 pm

Re: .ASS subtitles

Post by carl »

I will take a look at that now and see if I can reproduce it.
I found a mistake in the code which could explain what you're seeing - subtitle font sizing should be more consistent in the next version.
Ron
Posts: 44
Joined: Thu May 26, 2022 3:09 pm

Re: .ASS subtitles

Post by Ron »

Carl thank you for your thorough response...
Positioning is not read accurately
I was referring to the subtitle's vertical position of which I didn't include a sample on the file I sent...
Let's say that for whatever reason some subtitles need to be on the top of the screen (same distance from the edge as the regular subtitles below). DoM did not place the subtitle on top and instead positioned it around the [vertical] center of the screen.
2-line subtitles show with very wide line spacing which need to be adjusted
!.2 line spacing sounds right but somehow the spacing looks a little too wide for subtitles. However, when DoM imports an SRT file it doesn't add any line spacing (which I'd like to adjust to 110%). Of course this is all subjective on my part, but it would be nice if DoM would consistently use the same line spacing as with an imported SRT file... Maybe 1.1 would be a middle ground which the user could then adjust to wider spacing if preferred.
Font size is ignored because point size doesn't translate to the large cinema screen
I had 60pt for font size on Aegisub [1920x1080] which would look just about right on the cinema screen. But when it's imported to DoM the font looks larger relative to the screen. Keep in mind that even within Aegisub a font's point size is relative to the resolution of the video file and of course the same point size would look larger or smaller depending on the set video resolution.

Could DoM use the video resolution information in the .ASS file to calculate the relative size of the subtitles instead of using a fixed reference point?

Question:
When DoM is able to import the font type from an .ASS file will the outline/shadow information be imported as well?

PS.
I noticed that when formatting a font for outline/shadow within DoM, I was able to use the outline but the shadow option is offset too much to one side leaving a gap between the font and its shadow.
Ron
Posts: 44
Joined: Thu May 26, 2022 3:09 pm

Re: .ASS subtitles

Post by Ron »

If you change the font size in the .ASS does the subtitle not change in DoM?
I just did a test and changed a 60pt subtitle in half to 30pt and imported the .ASS file and it displayed on DoM looking the same size as before. Also the relative size of subtitles imported from an ASS file is very large compared to subtitles imported from an SRT subtitle.*

So in practical terms when I reduce the size within DoM the line spacing remains the same so it looks huge relative the new size. (that's why I got confused previously about line spacing). Then I have to adjust the line spacing by a lot just to conform the line spacing to the smaller font size on DoM's preview screen.

__
*I'm referring here to the relative font size on preview display
carl
Site Admin
Posts: 2338
Joined: Thu Nov 14, 2013 2:53 pm

Re: .ASS subtitles

Post by carl »

I just did a test and changed a 60pt subtitle in half to 30pt and imported the .ASS file and it displayed on DoM looking the same size as before. Also the relative size of subtitles imported from an ASS file is very large compared to subtitles imported from an SRT subtitle.*
Where did you change the font size? In the Style: line of the .ass, or somewhere else? I just tried changing the size in the style, and using a \fs in the subtitle, and both seem to work for me.
carl
Site Admin
Posts: 2338
Joined: Thu Nov 14, 2013 2:53 pm

Re: .ASS subtitles

Post by carl »

Could DoM use the video resolution information in the .ASS file to calculate the relative size of the subtitles instead of using a fixed reference point?
Perhaps - I think there's still missing information though - I'm not sure how knowing the video resolution helps us to know how many pixels high some text at 30 points should be ... I guess we just need to work out what people are expecting (presumably based on what Aegisub does).
Ron
Posts: 44
Joined: Thu May 26, 2022 3:09 pm

Re: .ASS subtitles

Post by Ron »

Where did you change the font size? In the Style: line of the .ass, or somewhere else? I just tried changing the size in the style, and using a \fs in the subtitle, and both seem to work for me.
I just did a quick back and forth: I had 60pts [which is the size I use on a 1920x1080 video using Aegisub] and then I went back and changed it to 30pts using the menu (Edit > Font size setting) then went back to DoM and the preview of the font looked the same.

I"m going to make a more sistematic test and label each subtitle...
Ron
Posts: 44
Joined: Thu May 26, 2022 3:09 pm

Re: .ASS subtitles

Post by Ron »

Perhaps - I think there's still missing information though - I'm not sure how knowing the video resolution helps us to know how many pixels high some text at 30 points should be ... I guess we just need to work out what people are expecting (presumably based on what Aegisub does).
You mentioned above that the relative size of an imported font in DoM was based on a height of 720. But if the relative size [viewing my Aegisub screen] is based on a resolution of 1920x1080 it will look smaller than what is displayed on DoM's preview.

In other words, using Aegisub as an example. If I have a font set at 60pts on a video resolution of 1920X1080, the same point size of 60pts will look bigger on a resolution of 1280x720 and even bigger on a resolution of 640 x 480.

I'm judging the relative size of my font viewing it on my subtitling software before I import it to DoM.
Post Reply