The WGBH National Center for Accessible Media
The Media Access Group at WGBH

MoPix® Motion Picture Access

woman using headphones to hear audio descriptions
woman using reflector to see captions
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Frequently Asked Questions

What is the Motion Picture Access Project (MoPix®)?

The MoPix Project is an initiative of the Media Access Group at WGBH. The Media Access Group includes a research and development unit – the WGBH - Carl and Ruth Shapiro Family National Center for Accessible Media (NCAM), and a production services unit comprised of The Caption Center and Descriptive Video Service.

MoPix was launched in 1992 to research and develop ways of making movies in theaters accessible to deaf, hard of hearing, blind, and visually impaired people through closed captions and descriptive narration.

Early development and evaluation of MoPix systems was funded by the National Institute on Disability and Rehabilitation Research (NIDRR), U.S. Department of Education, under grant #H133G40048.

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Who is WGBH? What does WGBH have to do with movies?

The WGBH Educational Foundation in Boston, Massachusetts, is a nonprofit institution whose purpose is to further the general education of the public by offering television, radio, and other telecommunications programs that inform, inspire, and entertain. WGBH is the country's largest public broadcasting station, producing more than one third of the PBS prime-time lineup. In addition to its broadcast activities, WGBH develops educational technologies and content for DVDs and Web sites. WGBH is also a pioneer in the field of media access.

WGBH has a proud tradition of making media accessible to underserved audiences. In 1972, The Caption Center at WGBH broke the silence barrier with the first captioned television show, The French Chef, on PBS. Today, The Caption Center captions more than 10,000 hours of television programming, Web-based video, music videos, DVDs, large-format films, and other media each year.

WGBH also is home to the world's first and largest description agency, Descriptive Video Service® (DVS®), and provides description on television, Web-based video, DVD and Blu-ray, movies and other visual media. DVS is the provider of description for PBS, CBS, Fox, the Turner Classic Movies cable channel, and Imax Corporation.

In 1993, WGBH created the WGBH National Center for Accessible Media (NCAM) to develop ways of making other forms of media accessible to underserved audiences. NCAM is dedicated to researching and developing access solutions for a broad range of media-- on the Web, in classrooms and distance learning environments, mobile media on handheld devices, in-flight entertainment and movies.

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What is the Rear Window® Captioning System? How does it work?

The patented Rear Window System (U.S. Patent # 5,570,944) is an innovative technology that makes it possible for exhibitors to provide closed captions for those who need or desire them without displaying them to the entire audience, and without the need for special prints or separate screenings.

The Rear Window Captioning System displays reversed captions on a light-emitting diode (LED) text display which is mounted in the rear of a theater. Patrons use transparent acrylic panels attached to their seats to reflect the captions so that they appear superimposed on or beneath the movie screen. The reflective panels are portable and adjustable, enabling the caption user to sit anywhere in the theater.

The Rear Window Captioning System was co-invented by WGBH and Rufus Butler Seder.

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How are the captions synchronized to the film?

The synchronization process differs depending on whether the system is being used in conventional movie theaters projecting 35mm film, theaters projecting digitally or specialty theaters (e.g. Imax®, Walt Disney World).

In conventional movie theaters projecting analog film, captions are fed to the LED panel by the Datasat (formerly DTS) digital audio system. The Datasat system provides multi-channel digital audio on CD-ROM. The caption data reside on a CD that plays alongside the other discs in the Datasat player. A reader head attached to the film projector reads a timecode track printed on the film and signals the Datasat player to play the audio and captions synchronous to the film. The Datasat player in turn sends the captions to the LED display. In theaters projecting digital film, the caption data is in the digital cinema package (DCP), and is routed via the digital cinema server to the LED panel. In specialty theaters, caption data can fed to the LED panel by a computer that is running special software that synchronizes the caption files to the film.

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How do Rear Window captions differ from open captions?

Open captions are similar to subtitles. They are projected onto the screen and visible to everyone in the theater. Theaters can provide open captions with 35mm film by purchasing a DTS server and a projector. Theaters that project films digitally can request from a film studio a digital cinema package (DCP) with open captions. No other special equipment is needed, theaters simply enable the open captions to play through the digital cinema projector, and onto the screen. Open-captioned films are generally presented at special screenings.

The Rear Window system is a way of providing closed captions. The captions are not on the film itself, so there is no need for a special screenings. The captions are visible (via a reflector) to only those patrons who choose to see them. The captions are available during regular scheduled presentations, for as long as the film plays in the theater.

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Do I need to sit in a certain seat to use the Rear Window Captioning System?

No. The Rear Window system is designed so that the captions are visible (via reflectors) from any seat in the theater. The reflectors are completely portable and designed to attach to any theater seat. However, depending on the size or layout of the theater and the location of the caption display, some seats may offer better viewing angles than others. Seats in the middle of the theater will generally offer the best view of Rear Window captions.

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How do I adjust my reflector?

Test captions are available before the show to enable Rear Window users to adjust their reflectors. Adjust the reflector by bending the gooseneck arm and tilting the plastic panel until you see the captions comfortably. The captions can be positioned over or just below the movie screen.

Some users report that the reflector works best if it is positioned low and further away from the body. This will also result in less need to readjust the reflector if you move in your seat. Experiment with different positions to find the one that works best for you.

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Can someone's head block my view of the captions?

Because the captions are projected from behind, they cannot be blocked by someone sitting in front of you. The caption display is hung high enough that heads behind you should not block the captions. However, if someone behind you stands up, they may temporarily block the captions, just as someone who stands up in front of you may temporarily block the picture. It is also possible for your own head to block the captions if your reflector is not adjusted properly. If this happens, move the reflector slightly to one side or try tilting the plastic panel.

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Does the reflector block the view of other patrons?

No. Other patrons' views of the movie screen are different from yours.

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Is there a cost to moviegoers to use Rear Window?

No. Moviegoers who use the Rear Window system pay normal ticket prices. There is no additional cost to the moviegoer to see the captions.

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What is DVS Theatrical® and how does it work?

DVS Theatrical makes it possible for exhibitors to provide descriptive narration for their blind and visually impaired patrons, without broadcasting it to the entire audience and without the need for special prints or screenings.

The descriptive narration is fed via infrared or FM transmitter to a small portable receiver, enabling blind and visually impaired moviegoers to hear the descriptions on headsets from any seat in the theater.

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What is descriptive narration?

Descriptive narration is a way of making visual media more meaningful to people with vision loss. Narrated descriptions provide information about key visual elements such as actions, settings, facial expressions, costumes, on-scree text and scene changes. The descriptions are inserted into pauses in the soundtrack and do not interfere with the dialogue.

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How are the descriptions synchronized to the film?

Descriptions are narrated and recorded onto an audiotape or disc that can be synchronized to the film as it is projected. Conventional movie theaters projecting 35mm film use the DTS digital audio system to play the descriptions. The DTS system provides multi-channel digital audio on CD-ROM. The descriptive narration resides on a CD that plays alongside the other discs in the DTS player. A special reader head attached to the film projector reads a timecode track printed on the film and signals the DTS player to play the audio synchronous to the film. The DTS player sends the descriptions to an infrared or FM emitter. In theaters projecting digital film, the description track is data in the digital cinema package (DCP) which is routed to the emitter. The emitter, in turn, sends the descriptions to the theater, where they can be heard on headsets that are equipped with receivers.

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Do I need to sit in a certain seat to hear the descriptive narration?

No. The headsets are completely portable and enable you to hear descriptions from any seat in the theater.

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Why isn't the entire soundtrack in the headsets?

When DVS Theatrical was first introduced in large-format theaters, WGBH conducted field tests and focus groups to determine whether users preferred to have just the descriptive narration or a mix of the narration and the soundtrack in the headsets. Although responses varied, many users remarked that the full mix in the headsets produced an echo effect that was disturbing.

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How do I adjust the headsets to hear the descriptions properly?

Headsets will vary from theater to theater. Some may provide actual headphones, similar to a personal stereo system; others may use systems with a small receiver and a single ear piece. Theater staff should provide you with written or oral instructions when they give you the headset. Usually there is an on/off switch and a volume control (some headsets may have separate volume controls for each ear). Adjust the volume control to a level that is comfortable for you. With standard headsets, you may also want to experiment with wearing the headset so that it is over one ear only.

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How much does it cost to install the Rear Window System and DVS Theatrical?

Costs vary from theater to theater depending on factors like theater size and existing equipment. The cost of the equipment for providing both Rear Window captions and DVS Theatrical in a theater projecting 35mm film is estimated at approximately $12,000. For theaters projecting films digitally, the cost will be less by approximately $4,500 as the DTS server is no longer necessary to sync the captioning and description to the film.

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Will DVS Theatrical interfere with the assistive listening system that the theater provides for hard-of-hearing patrons?

No. The system that provides DVS Theatrical will be on a different frequency than the assistive listening system. If properly installed, one will not interfere with the other.

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I am a theater owner/manager and am interested in purchasing the Rear Window Captioning System and equipment for providing DVS Theatrical. How do I get more information?

Theaters can contact WGBH for general information about MoPix, the Rear Window Captioning System and DVS Theatrical. While WGBH does not sell the various equipment components, we do have contact information for companies that do.

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Once a theater has the Rear Window and DVS Theatrical systems installed, how do they get the captions and descriptions?

Once a movie has been captioned and described, conventional theaters projecting 35mm film can obtain the captions and descriptions on CDs along with the DTS CDs that contain the digital audio for the film. For theaters projecting film digitally, closed captioned and described digital cinema packages (DCPs) can be requested from the movie studios. For specialty theaters, Captions are provided on a floppy disk and the descriptions are provided in the audio format appropriate for the theater.

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How does a studio get its films captioned/described?

Studios can contact WGBH to arrange for the creation of both the captions and descriptions. WGBH is home to The Caption Center and Descriptive Video Service, the world's most experienced captioning and description agencies.

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How much does it cost to caption and describe a film?

Prices for captioning and description of films vary by length of film, turnaround time and other factors. Because the captions and descriptions are not on the film itself, there is no need to create special prints. Plus, once the captions and descriptions have been created, they can be reused when the film is released in other formats such as DVD and streaming video.

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What kind of turnaround time is required to create closed captions and descriptive narration?

WGBH is accustomed to fast turnaround times and can work with studios to accommodate their schedules. However, to ensure that the captions and descriptions are available in time for a film's release date, studios should provide materials as soon as they are available.

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How are the captions and descriptions created?

Closed captions and descriptive narration are created as part of a movie's post production process. Once a film has been finalized, a script and a copy of the film are provided to WGBH's Los Angeles production office.

Trained caption writers transcribe the audio portion of the film using a specially designed computer program, adding or adapting information to give deaf and hard-of-hearing viewers a full sense of the events occurring on screen (e.g. on- and off-screen sound effects, voices, attitude). The caption writers rely on timecode to carefully time and place the captions. They also position the captions (left, right, or center) to indicate who is speaking.

Descriptions are written by specially trained writers called describers. A describer initially listens to the film without watching it, in order to approximate the experience of a person who has limited or no vision. The describer pays close attention to what is already communicated by the soundtrack. The describer uses specially designed computer software to map out the pauses in the movie and then crafts the most expressive and effective description possible in the space available. After a script is written, it is edited and rechecked several times. The script is checked for timing, continuity, accuracy, and a natural flow. Professional narrators then read the script while watching and listening to the program.

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What happens to the captions/descriptions when a movie is released for DVD, online, etc.?

Once a film has been captioned and described, it is not necessary to repeat the captioning and description process when the film is released in other formats. Some reformatting of the existing caption and description files can be necessary due to changes in the transferred version of the film. However, reformatting is a simple and inexpensive process.

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When will the Rear Window Captioning System and DVS Theatrical be available in theaters across the country?

We are encouraged by the tremendous interest from the motion picture industry and movie fans who so appreciate these access services, and we expect theaters will continue to adopt these technologies. In the meantime, WGBH continues to work with the industry to explore strategies that will result in widespread availability of these services.

While we can't say when these technologies will be in your neighborhood theater, you can check our Web site regularly for updated information and contact us directly at 617 300-3700, or via email at if you'd like to advocate for an installation of a MoPix system near you. You can also sign up to be added to our email list.

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Can I get more information about how captioning and description will work in digital cinema?

The movie industry is embarking on a transition between analog film and digital projection of film. D-cinema makes sending films to theaters more cost effective (via data files, vs. reels of film as is the case now). The quality of the picture and sound for films is sharper and clearer, with no degradation due to wear and tear on film played again and again (as is the case with analog film).

WGBH's Media Access Group is involved in this transition through our work with studios and theater chains to make films accessible now, and with the manufacturers of digital cinema equipment to ensure that films and theaters remain accessible into the future.

WGBH, through its Carl and Ruth Shapiro National Center for Accessible Media (NCAM), collaborated with technology developers, equipment manufacturers, film studios and exhibitors in the development of specifications for digital cinema that include provision of access features. The resulting Digital Cinema System Specification includes information about the insertion and transport of caption, subtitle and description data in the digital cinema package sent to theaters, and the playout of same in auditoriums.

This work has proceeded through the voting, refinement and approval process within the Society of Motion Picture and Television Engineering (SMPTE) standards committee. The SMPTE standard details technical implementation of access features (captions, subtitles and descriptions) in digital cinema, both the transportation of digital files to theaters, and the display (captions/subtitles) or delivery (description/alternative-language audio) to end users. This could be via MoPix systems, or via any device that may be developed to serve the market of film fans with sensory disabilities or alternative-language preferences. You can follow related news and activities around this topic at NCAM's Access to Digital Cinema site which also includes a set of frequently asked questions (FAQ) specifically about access features and digital cinema.

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What can I do to convince my theater to install these technologies? How do I get Rear Window/DVS Theatrical in my theater?

You can write to your local theater and tell them you would like these technologies to be available. You can direct the theater to the MoPix home page or tell them to contact WGBH for more information.

You can also write to the members of the motion picture industry who have participated in this initiative to let them know that you appreciate their efforts to make movies accessible. Send your letters to us and we will forward them to the proper contacts.

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Contact Information

For information about WGBH's Motion Picture Access efforts, contact:

WGBH Educational Foundation
Motion Picture Access Project
Carl and Ruth Shapiro Family National Center for Accessible Media (NCAM)

One Guest Street
Boston, MA 02135
Web site:
Phone: (617) 300-3400
FAX: (617) 300-1035

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