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ENLARGE
Closed captioning and how it makes media more accessible to everyone was the theme of the recent open house at Ensemble Designs in Nevada City.
About 150 people visited the event that featured technology demonstrations and presentations from eight companies including Tektronix, KTXL-TV, AJA and CaptionMax. Visitors came from local businesses, Sacramento TV stations and Los Angeles post houses to learn about closed caption technology for use in high-definition television applications. Deborah Pomeroy provided interpreting services for the deaf and hard-of-hearing attendees.
Attendees had questions about the process of creating closed captions, why caption timing can be off with respect to video material, and what the implications of high definition video are for closed captioning.
Emily Bell of CaptionMax demonstrated offline captioning, the kind used for shows like 30 Rock and Law and Order.
Two kinds of closed captioning are used in television programming; offline and realtime. Offline captioning is used for prerecorded television programming. Realtime captioning is used for live events such as sports and Presidential addresses. Realtime caption writers train as court reporters.
To create caption text and timing, the caption writer watches a movie or program and types in dialog and descriptions of sound effects and music. Caption writers also do lots of research on every topic imaginable, often needing to look up the correct spelling of proper nouns and the exact wording of idioms.
After entering all of the captions and description data into a caption creation software program, a closed caption data file is exported. The data file and the TV program are both sent to an encoder where they are combined.
The closed caption event featured a comparison of several consumer TV sets and three professional-grade video monitors from Marshall, Plura and TVLogic. Home television sets receive closed caption data along with the video and audio signals. The video monitor decodes the closed caption data and displays it. When caption data is displayed on the screen, it's referred to as open captions.
The newer CEA-708 specification for closed caption data in high definition provides more challenges to the decoder. Closed caption data is carried along with the video signal, whether it's an SD (standard definition) or HD (high definition) signal.
The conclusion was that not all televisions are created equal in their ability to decode and display captions. Some TVs lagged in displaying the captions or cut off part of the sentences. Other units were true to the caption data and displayed very well.
Jack Davis, Director of Engineering at KTXL-TV Fox 40 in Sacramento discussed closed caption compliance for broadcasters and exactly how Fox 40 has implemented closed captioning technology. In addition to his engineering responsibilities at the station, Davis fields calls from viewers who have trouble with their captions at home. Often the user settings in the TV set are the culprit. For example, if Spanish captions are displaying instead of English, or vice-versa, the TV set may need to be changed from CC1 (service1) to CC2 (service 2) in order to display the desired language.
Tektronix and Ensemble Designs both showed test and analysis equipment that is used in television broadcast facilites to determine if the station has a problem or not with closed caption compliance. Ensemble Designs has a closed caption test generator that outputs a challenging set of caption data that is fed to broadcast equipment. If the captions are displayed correctly then the equipment is passing the data properly. The station might also use equipment from Tektronix to diagnose exactly why there might be a problem with the closed caption data by drilling down into the syntax of the digital signal.
Ensemble Designs and AJA both showed video processing units that convert standard definition video to high definition. TV stations rely on these upconverters to faithfully transcode the standard definition CEA-608 closed caption data to high definition CEA-708.
About 150 people visited the event that featured technology demonstrations and presentations from eight companies including Tektronix, KTXL-TV, AJA and CaptionMax. Visitors came from local businesses, Sacramento TV stations and Los Angeles post houses to learn about closed caption technology for use in high-definition television applications. Deborah Pomeroy provided interpreting services for the deaf and hard-of-hearing attendees.
Attendees had questions about the process of creating closed captions, why caption timing can be off with respect to video material, and what the implications of high definition video are for closed captioning.
Emily Bell of CaptionMax demonstrated offline captioning, the kind used for shows like 30 Rock and Law and Order.
Two kinds of closed captioning are used in television programming; offline and realtime. Offline captioning is used for prerecorded television programming. Realtime captioning is used for live events such as sports and Presidential addresses. Realtime caption writers train as court reporters.
To create caption text and timing, the caption writer watches a movie or program and types in dialog and descriptions of sound effects and music. Caption writers also do lots of research on every topic imaginable, often needing to look up the correct spelling of proper nouns and the exact wording of idioms.
After entering all of the captions and description data into a caption creation software program, a closed caption data file is exported. The data file and the TV program are both sent to an encoder where they are combined.
The closed caption event featured a comparison of several consumer TV sets and three professional-grade video monitors from Marshall, Plura and TVLogic. Home television sets receive closed caption data along with the video and audio signals. The video monitor decodes the closed caption data and displays it. When caption data is displayed on the screen, it's referred to as open captions.
The newer CEA-708 specification for closed caption data in high definition provides more challenges to the decoder. Closed caption data is carried along with the video signal, whether it's an SD (standard definition) or HD (high definition) signal.
The conclusion was that not all televisions are created equal in their ability to decode and display captions. Some TVs lagged in displaying the captions or cut off part of the sentences. Other units were true to the caption data and displayed very well.
Jack Davis, Director of Engineering at KTXL-TV Fox 40 in Sacramento discussed closed caption compliance for broadcasters and exactly how Fox 40 has implemented closed captioning technology. In addition to his engineering responsibilities at the station, Davis fields calls from viewers who have trouble with their captions at home. Often the user settings in the TV set are the culprit. For example, if Spanish captions are displaying instead of English, or vice-versa, the TV set may need to be changed from CC1 (service1) to CC2 (service 2) in order to display the desired language.
Tektronix and Ensemble Designs both showed test and analysis equipment that is used in television broadcast facilites to determine if the station has a problem or not with closed caption compliance. Ensemble Designs has a closed caption test generator that outputs a challenging set of caption data that is fed to broadcast equipment. If the captions are displayed correctly then the equipment is passing the data properly. The station might also use equipment from Tektronix to diagnose exactly why there might be a problem with the closed caption data by drilling down into the syntax of the digital signal.
Ensemble Designs and AJA both showed video processing units that convert standard definition video to high definition. TV stations rely on these upconverters to faithfully transcode the standard definition CEA-608 closed caption data to high definition CEA-708.
