Cinepedia

The Technology Behind The Big Screen

  • System
    • System Basics
    • DCI & SMPTE
  • Packaging
    • DCP
    • The Composition
    • Title Versions
    • Composition Playlist (CPL)
    • Track Files
    • Track File Encryption
    • Packing List
    • Additional Metadata
    • Interop DCP / SMPTE DCP
  • Security
    • Trust Model
    • Encryption
    • Trusted Device List
    • Digital Certificate
    • KDM
    • Media Block
    • Security Log
  • Picture
    • Picture Introduction
    • Color Distribution & Display
    • Color Gamut
    • Contrast & Dynamic Range
    • Resolution & Aspect Ratio
    • Light
    • Picture Track File & Compression
    • Projector Image Formation
    • Projection Screens
    • Stereoscopic 3D
  • Sound
    • Cinema Sound Basics
    • Sound Formats and Soundfields
    • MainSound Track File
  • Accessibility
    • Accessibility Overview
    • Accessibility & Audio Track File
    • Timed Text Track Files
    • Reel Flexibility for Timed Text
    • Communications for Off-Screen Timed Text
  • FAQs
    • Technology FAQs
    • Business FAQs
    • Accessibility FAQs
  • History
    • Early History
  • Terminology
  • References
  • Interop DCP
  • menuToggle Mobile Menu
  • Back to Top

Timed Text Track Files

section-1302

Open Subtitles, Closed Subtitles, Open Captions, and Closed Captions are each a type of Timed Text essence, where each type is targeted to a specific audience. Timed Text essence may be included in the Composition as a Timed Text Track File. While the essence is referred to as Timed Text, the actual track files may also reference and carry graphics.

The essence of Timed Text is defined in SMPTE ST 428-7 DCDM – Subtitle.  However, the purpose of the Timed Text Track File is identified in the Composition Playlist (CPL).  SMPTE ST 429-7 DCP – Composition Playlist defines the MainSubtitle element for Open Subtitle essence.  This definition is extended in SMPTE ST 429-12 DCP – Caption and Closed Subtitle to include the additional elements of ClosedSubtitle, MainCaption, and ClosedCaption.

SMPTE Timed Text essence is wrapped as an MXF track file in accordance with SMPTE ST 429-5 DCP – Timed Text Track File.  By doing so, SMPTE Timed Text assets can be encrypted and managed in the same manner as Picture and Sound track files.  As explained below, Timed Text essence may have fonts and graphics associated with it.  For SMPTE Timed Text, the associated files are wrapped with the essence in the Timed Text Track File.  In contrast, Interop Timed Text essence are delivered in the package as an XML file, with the associated font and graphics essence also delivered as separate files.

Open Subtitles and Open Captions

Open Subtitles and Open Captions refer to text superimposed on the picture displayed in the auditorium. As such, they are visible to all members of the audience. Open Subtitles are typically displayed on-screen as text in a language other than the language of the movie’s sound track. The intent of the Open Subtitle is to translate the dialog of the sound track for the audience. Open Captions are also typically displayed on-screen as text, but in the same language as the movie’s sound track, with the intent to convey the dialog and action of the movie to those who are hearing-impaired or deaf. Graphics may also be displayed with on-screen timed text. Open Subtitle track files are identified in the CPL as MainSubtitle, and Open Caption track files are identified as MainCaption. A Composition may contain only one MainSubtitle, or one MainCaption file.

Timed Text is managed differently in SMPTE and Interop DCP. Both packaging methods employ XML for Timed Text essence, but each defines the XML differently. (The difference in Timed Text essence has proven to be one of the stumbling blocks in the adoption of SMPTE DCP.) In addition, Interop delivers Timed Text as an XML file in the Composition package, while SMPTE DCP wraps Timed Text XML essence in MXF. This is further explained below.

Interop Timed Text essence is based on a proprietary format introduced by Texas Instruments called CineCanvas™.  The latest CineCanvas documentation is available on the Interop DCP page. The CineCanvas file is in XML format, and included in the Composition as an XML file. Text properties and associated actions include language, font, timing of display, fade up/down properties, and the text position properties of direction, horizontal alignment and position (left, center, right), and vertical alignment and position (top, center, bottom). Image (graphics) properties include timing of display, fade up/down properties, horizontal alignment and position, and vertical alignment and position. Font and graphics files may be included with the distribution.

Timed text essence in SMPTE DCP is defined in SMPTE ST 428-7 DCDM – Subtitle. The SMPTE Subtitle format provides a more sophisticated control of display, placement, and font properties over CineCanvas, and includes 3D text. SMPTE Subtitle also includes Ruby text, small annotations used to guide pronunciation placed alongside logographic characters used in the Chinese, Japanese, and Korean languages. As with CineCanvas, horizontal alignment and position is described in terms of left, center, right, and vertical alignment and position in terms of top, center, bottom. Font and graphics files may be included with the distribution.

Closed Captions and Closed Subtitles

Closed Captions and Closed Subtitles are text-only recitations directed to a personal display, and not visible to the general audience (i.e., off-screen).

SMPTE ST 428-10 DCDM Closed Caption and Closed Subtitle sets forth a set of constraints applied to Timed Text essence for the off-screen applications of Closed Captions and Closed Subtitles. The constraints essentially limit the interpretation of positioning elements in the XML document to the vertical position. The same closed caption and closed subtitle constraints applied to SMPTE off-screen Timed Text may also be applied to CineCanvas™ off-screen applications in Interop distributions. Unlike Open Subtitles and Open Captions, Closed Subtitles and Closed Captions may carry up to six (6) versions of off-screen Timed Text Track Files in one Composition, one language per Track File. It is up to the personal display provider to provide on-demand access to the multiple track versions. The packaging of off-screen Timed Text Track Files deserves special attention, as explained in the Reel Flexibility for Timed Text section.

Interop DCP Closed Caption files are a constrained version of  the CineCanvas format.  The constraint documentation is available on the Interop DCP page.

last changed 2019-03-11 in Accessibility by MK

→  Reel Flexibility for Timed Text
←  Accessibility & The Audio Track File

About

About Cinepedia

Interop DCP

The Interop DCP documentation below is provided for those who seek interoperability with older … more

An Early History of Digital Cinema

Public demonstrations of modern day digital cinema began in 1999 ...

copyright © 2016 - 2023 mkpe consulting llc

We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept”, you consent to the use of all cookies.
Cookie settingsACCEPT
Manage consent

Privacy Overview

This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may affect your browsing experience.
Necessary
Always Enabled
Necessary cookies are absolutely essential for the website to function properly. These cookies ensure basic functionalities and security features of the website, anonymously.
CookieDurationDescription
cookielawinfo-checbox-analytics11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
cookielawinfo-checbox-functional11 monthsThe cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
cookielawinfo-checbox-others11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
cookielawinfo-checkbox-necessary11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
cookielawinfo-checkbox-performance11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
viewed_cookie_policy11 monthsThe cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data.
Functional
Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features.
Performance
Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors.
Analytics
Analytical cookies are used to understand how visitors interact with the website. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc.
Advertisement
Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. These cookies track visitors across websites and collect information to provide customized ads.
Others
Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet.
SAVE & ACCEPT
Powered by CookieYes Logo