35mm and 70mm subtitle system

[Marcel Birgelen]

But seriously... in multi language regions you could do interesting things like render dual language subtitles too, 3 language presentations if you include the ST native language.

Well... right over here in a small, but very strange country called Belgium, they make beer and projectors... but they also speak no less than three official languages. In the cinema, it's normal to see at least two of them in the subtitles...

[Javier de Blas]

Very nice! I'm always very impressed when someone comes up with a home-brew solution
to a technical projection problem. Good work! What I often wish I had here was a remote
time-code display for XD-10. (but I should hook you up with one of my film-maker friends
who built his own Steadicam™! ) lol

I know it's a really bad video hahahaha. Anyway, Jim. I could build you that pretty easily. I can make one of my decoders to send the time code through wifi so you can check it on a computer or mobile phone.

If you are interesting on building it I can make a prototype and show it to you.
Contact me by email javier.deblas@icloud.com if you want to it.

[Javier de Blas]

Well... right over here in a small, but very strange country called Belgium, they make beer and projectors... but they also speak no less than three official languages. In the cinema, it's normal to see at least two of them in the subtitles...

Following the multilanguage subtitle display topic. I didn't even think about it. But that's super easy to implement. I'll think about it for later versions.

[Josh Jones]

I have a similar need here. In the collection is a foreign language film with a SRD track. I have heard, but never investigated, that SRD decoders spit out a block number via serial, sort of like a timecode. I wonder if something like this could be used in a similar fashion to add subtitles to films in SRD.

Also, I assume your cleaner circuit is just a threshold detector using a comparator or a schottky type level detector?

[Ryan Gallagher]

Well... right over here in a small, but very strange country called Belgium, they make beer and projectors... but they also speak no less than three official languages. In the cinema, it's normal to see at least two of them in the subtitles...

Being in the US my familiarity with subtitle systems beyond what is offered by the DCI packages is iffy at best. How do they implement dual titles? Does DCI spec already cover that?

I expect if it was implemented with any of the pre-existing captioning or titles display for 35/70mm it was also very home brew to get an additional set of subtitles. Maybe two video/title capable processors daisy chained?

[Ryan Gallagher]

About not altering the 70mm presentation with the digital projection, it's been an odyssey (get it? hahaha).
At first I tried to use a little home projector, but it was simply not powerful enough to much the 5000w xenon of the 70mm, in bright scenes it was simply unreadable. That's why we used the laser projector instead. What I dis was, first, set the digital projection as low as possible. Then create a cardboard masking attached to the window of the booth (you can see it a bit in the video). As a last step I rendered the subtitles yellow and added a yellow masking to the cardboard, so the rest of the light would be more blocked. And you may ask now. Why there's no such filter on the video. Well, universal wanted white subtitles for the Odyssey, so we had to remove the yellow filter. I can't win them all.

Also, I forgot to mention, the idea of a subtitle screen was also mentioned, but the cinema did not want to do it. (At least we have masking on the screen to get perfect 2.20 in an 2.35 screen, a lot of cinemas don't )

Ahh so all of the above were considered/pursued! I wasn't sure if you had a laser DCI projector or not. The note about title coloring is tragically funny. Do all this work to get their titles on screen so the movie can happen, and then they have this one last demand for you. haha.

I have a similar need here. In the collection is a foreign language film with a SRD track. I have heard, but never investigated, that SRD decoders spit out a block number via serial, sort of like a timecode. I wonder if something like this could be used in a similar fashion to add subtitles to films in SRD.

I believe timecode from block count has been discussed in some other threads too. But if you can manage that translation it probably wouldn't be much extra programming with a device like Javier's to react to it similarly to the DTS timecode.

There are probably other ways too, if you knew the print was intact and frame perfect (or had black replacements, or records of the frame losses). You could borrow a page from Michael's "Tach Decoder" methods to generate a timecode and ignore the block count (or use his actual hardware to go directly to DTS timecode). I think the most recent discussion of his methods were here:
https://www.film-tech.com/vbb/forum/...-bloody-affair

[Javier de Blas]

I have a similar need here. In the collection is a foreign language film with a SRD track. I have heard, but never investigated, that SRD decoders spit out a block number via serial, sort of like a timecode. I wonder if something like this could be used in a similar fashion to add subtitles to films in SRD.

Also, I assume your cleaner circuit is just a threshold detector using a comparator or a schottky type level detector?

As Ryan says. If I can get a something like a timecode from dolby digital it could be done. But I must admit that I'm pretty unfamiliar with SRD. When I bought my CP500 with hopes of running it. I found out that some of the digital boards where toasted for good. And they made the processor go on an endless loop of rebooting itself going into bypass mode. So, I did as the spanish saying goes, perro muerto se acabo la rabia, which roughly means, If the dog is dead you don't have to care about rabies. I took out all digital related boards (except the ones needed for matrix decoding and eq) and called it a day. Now I'm happy with optical and dts. Of course, at some point I will have to fall into the rabbit hole of SRD.

And yes, the cleaner is a threshold detector well adjusted and to logic ANDs on series.

[Connor Loosemore]

I have a similar need here. In the collection is a foreign language film with a SRD track. I have heard, but never investigated, that SRD decoders spit out a block number via serial, sort of like a timecode. I wonder if something like this could be used in a similar fashion to add subtitles to films in SRD.

Also, I assume your cleaner circuit is just a threshold detector using a comparator or a schottky type level detector?

Yes, this is pretty easily achievable. The DA-20/CP-500 serial port will output a stream of information while running SR*D film which includes the block and reel number. Unfortunately, Dolby never set a hard rule for labs to follow relating block number to FFOA, but the audio block number corresponding to the FFOA is roughly 168. This makes it a bit tricky for syncing audio, as you have to know exactly what block number each of your reels start on. For subtitles I suspect it would be okay to just make an assumption about the first block number, since the variation in starting block numbers is rather small. One other important thing to note is that SR*D audio blocks run at 93.75 per second - despite there being 96 physical blocks, 3 in every 128 will be "bogus" (containing non audio data).

[Javier de Blas]

Hello everyone! I've been reimplementing my system to make it more error proven as an isolated linux utility. In the latest updates I've implemented server send events, so the decoder can send the data to any other pc in the same network. That way it would be also possible to run subtitles on a tv screen under the projection screen like opera houses do.

https://www.facebook.com/share/r/1DUxBq2e7R/

[Marco Giustini]

maybe it's just me but it shows an error.

[Marcel Birgelen]

Also, is it just me or isn't this a project worthy sharing on GitHub rather than a dying social media platform that everybody hates?

[Ryan Gallagher]

Also, is it just me or isn't this a project worthy sharing on GitHub rather than a dying social media platform that everybody hates?

It is not unusual for developers to want to reach a certain level of polish before they put their repos up. Facebook kinda makes sense because there are some reasonably large projectionist forums there too, sharing here and there is just targetted sharing in an alpha phase?

Some of our booth friends who do a lot of contract festival projection work even have their own slack channel (or something equivalent more modern than facebook) for community advice/problem solving.

I'm not interested in facebook, but I'd be game for an invite if anyone else is in one of those other chatty spaces of peer projectionists.

(PS I also get an error from the FB link)

[Javier de Blas]

image.pngBig steps on automatization done!
Now the program opens the subtitle files automatically once it reads the film ID.
It can also change languages on the fly with the press of a button.
Plus all serial communications have been locked secure to prevent fail, identifying automatically the decoder now too

The software is almost done. In no time I'll get my hands into building a proper rack chasis.