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» Film-Tech Forum   » Operations   » Digital Cinema Forum   » Accessing subtitles track on DCP server?

   
Author Topic: Accessing subtitles track on DCP server?
Tony Tse
Film Handler

Posts: 3
From: Auckland, New Zealand
Registered: Jun 2017


 - posted 07-07-2017 05:00 AM      Profile for Tony Tse   Email Tony Tse   Send New Private Message       Edit/Delete Post 
Hello,

I am working on a personalized device to improve closed caption technology. I have talked to local cinemas here (they have Doremi DCP server) and they are willing to help me do some testing.

Is it possible to accessing the subtitles if they are available? For example, call the server to return the line at current video time.

I am an engineer (and hard of hearing!) but I don't work specifically in DCP so any info would be appreciated [Smile] .

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Marcel Birgelen
Film God

Posts: 2388
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012


 - posted 07-07-2017 06:30 AM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
You should check SMPTE ST430-10 and SMPTE ST430-11, both describe a protocol to receive closed captions from DCI servers compatible with the protocol (which covers most of them).

Both specifications are available on-line, though not necessarily for free. The protocol itself is royalty free though.

Other routes, like reading it directly from the DCP are problematic, as most DCPs for commercial distribution are encrypted and your equipment would need to become part of the "secure chain", which would require DCI certification. Furthermore, you would still need to implement SMPTE ST430-10 in order to synchronize with the playback.

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Tony Tse
Film Handler

Posts: 3
From: Auckland, New Zealand
Registered: Jun 2017


 - posted 07-07-2017 07:07 AM      Profile for Tony Tse   Email Tony Tse   Send New Private Message       Edit/Delete Post 
Thanks, Marcel! That's the kind of information I needed.

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Harold Hallikainen
Jedi Master Film Handler

Posts: 678
From: Denver, CO, USA
Registered: Aug 2009


 - posted 07-07-2017 09:45 AM      Profile for Harold Hallikainen   Author's Homepage   Email Harold Hallikainen   Send New Private Message       Edit/Delete Post 
The SMPTE standards used in closed captioning are described at http://ftp.uslinc.com/ftp/Products/IRC-28/Documents/Manual/IRC-28C_Manual.pdf#page=6 . A streaming log out of a QSC/USL IRC-28C is shown at http://ftp.uslinc.com/ftp/Products/IRC-28/Documents/Manual/IRC-28C_Manual.pdf#page=14 . This gives some idea of the communications that goes on to deal with closed captions.

Finally, many servers also support Rear Window closed captioning. These servers send captions out an RS232 port at the time the caption is supposed to run. The text is ASCII with the text of each line in reverse order (right to left). There are also control codes to clear the display and select which line the text is to appear on. The RS232 port was pretty common on external servers, but I don't think it was brought over to systems where the server and IMB are combined and are in the projector.

Good luck!

Harold

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Stephan Shelley
Jedi Master Film Handler

Posts: 615
From: castro valley, CA, usa
Registered: Nov 2014


 - posted 07-07-2017 07:45 PM      Profile for Stephan Shelley   Email Stephan Shelley   Send New Private Message       Edit/Delete Post 
Should point out that Doremi servers require a license to enable the closed captions. Without the license in place it will not work. Depending on the age of the server you might be able to download the license from Dolby/Doremi. If they are not there they have to be purchased from Dolby.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 11982
From: Annapolis, MD
Registered: Dec 1999


 - posted 07-07-2017 10:12 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
Dolby has made the CC license available to all servers now at no charge.

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Stephan Shelley
Jedi Master Film Handler

Posts: 615
From: castro valley, CA, usa
Registered: Nov 2014


 - posted 07-07-2017 10:21 PM      Profile for Stephan Shelley   Email Stephan Shelley   Send New Private Message       Edit/Delete Post 
Steve you sure it is all. Last I heard it was those under software warranty original 3 years or extended. Those not one had to purchase.

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Harold Hallikainen
Jedi Master Film Handler

Posts: 678
From: Denver, CO, USA
Registered: Aug 2009


 - posted 07-07-2017 11:26 PM      Profile for Harold Hallikainen   Author's Homepage   Email Harold Hallikainen   Send New Private Message       Edit/Delete Post 
Steve is correct. See http://ftp.uslinc.com/ftp/Products/IRC-28/Documents/Technical/DolbyDoremiLicense170213.html .

Harold

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Stephan Shelley
Jedi Master Film Handler

Posts: 615
From: castro valley, CA, usa
Registered: Nov 2014


 - posted 07-08-2017 12:02 AM      Profile for Stephan Shelley   Email Stephan Shelley   Send New Private Message       Edit/Delete Post 
well a 9 plex that I help out with that has very old Doremi servers only 3 can be found in that list. the other six are not there. I will contact Dolby support and see what they say.

This is what Dolby said in Feb. 2017 "Effective immediately, we will be including the ACC-DCP license as part of our standard software release. This license is required to allow accessibility equipment to communicate with Dolby and Doremi servers. This also means that all units under software maintenance or extended warranty will have the entitlement available to them."

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Stephan Shelley
Jedi Master Film Handler

Posts: 615
From: castro valley, CA, usa
Registered: Nov 2014


 - posted 07-08-2017 03:37 PM      Profile for Stephan Shelley   Email Stephan Shelley   Send New Private Message       Edit/Delete Post 
I stand corrected but not all can be found on the FTP site the ones missing I had to go through:

http://www.dolbycustomer.com/cinema/FeatureDlms

and have it search for them.

Stephan

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Tony Tse
Film Handler

Posts: 3
From: Auckland, New Zealand
Registered: Jun 2017


 - posted 07-13-2017 03:27 AM      Profile for Tony Tse   Email Tony Tse   Send New Private Message       Edit/Delete Post 
Thanks for replies! Just another quick question, is it possible to test the SMPTE protocol on an emulator? It would help ironing out the bugs in my software.

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Marcel Birgelen
Film God

Posts: 2388
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012


 - posted 07-13-2017 03:48 AM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
I'm afraid nobody has built an emulator to simulate ST430-10 and ST430-11 interactions and made it publicly available. The industry is really pretty small, so the amount of third-party tools is somewhat limited. Obviously, if you do not have constant access to a DCI server, it will be hard to test this part of your interface.

But since you're developing an accessibility implementation as an add-on to their offer, you might try to contact someone at e.g. Dolby, Barco, Christie, GDC, etc. Maybe one of them can help you with some kind of emulator or can provide other means to test your interface.

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