Closed Captions. Questions. Jan Ozer #janozer 11/20/2014

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Closed Captions

Jan Ozer

jozer@mindspring.com

www.streaminglearningcenter.com

#janozer

Questions

 For more information, check out the book

 http://bit.ly/Ozer_multi

 “A beacon of light in a valley of half-knowledge”

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Agenda



Introduction



Definitions



Creating captions



Live



VOD



Choosing/using a caption format

Introduction



What are closed captions



Who has to caption?

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What Are Closed Captions?



Closed captions

 Designed for deaf or hard of hearing  Incorporate all elements of audio experience:  Background sounds  Identify of speaker

 Closed can be disabled; open are burned in



Subtitles

 Convert production to different language

 Translate from one language to another

 Speech

 Signs or other written documents

 Not background noises and sounds

Who Has to Caption?



Federal agencies (and those

receiving federal funds) - Section

508 of the Rehabilitation Act

 "All training and informational video

and multimedia productions which support the agency's mission, regardless of format, that contain speech or other audio information necessary for the comprehension of the content, shall be open or closed captioned."

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Who Has to Caption?

 Broadcasters: Twenty First Century Communications and Video Accessibility Act of 2010

3PlayMedia - http://bit.ly/ozercap1

Caption Requirements



Caption Quality

 IP video captions must be at least the same quality as TV captions. Quality of captions will be assessed on completeness, placement, accuracy, and timing.



Caption Style and End-User Control

 Following controls required - Font size, Font style, Character color, Opacity, Edge attributes, Caption background, Language selection, Preview/setting retention

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Caption Requirements



Caption Formats

 SMPTE-TT (Society of Motion Picture and

Television Engineers Timed Text) caption format is a “safe harbor interchange and delivery format.”  SMPTE-TT is not required, but recommended by

the FCC. Devices that support SMPTE-TT are in compliance in regard to functionality.

Other Potential Groups



Schools, public universities, towns and

municipalities (maybe)

 Title II of the Americans with Disabilities Act  Section 504 of the Rehabilitation Act of 1973

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Other Reasons to Caption



To expand viewers to hearing impaired



To enable viewing in loud environments



Improving video SEO

 RAMP is the most prominent supplier here

 Fox News, Golf Channel, Thomson Reuters

Definitions



Broadcast standards



Digital formats

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Broadcast Formats

 CEA-608 captions – analog broadcasts

 60 characters a second

 Limited character set

 Embedded in line 21 of broadcast (called vertical blanking interval)

 CEA-708 – captions for digital broadcasts

 Much more flexible character set and colors

 Generally embedded as text track into transport stream

 DCMP’s Caption Key Guide is gold standard for best practices  http://www.dcmp.org/captioningkey/

608 vs. 708

http://bit.ly/ozercap3 http://bit.ly/ozercap5 Streaming captioning is essentially CEA-608

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608 vs. 708 (from CPC Web)

http://bit.ly/ozercap2

Digital Caption Formats



Too many to list. Prominent ones include

 SCC – Scenarist Closed Caption – good mezzanine

 SMPTE-TT (Timed Text) – FCC safe harbor format

 TTML – Timed Text Markup Language

 WebVTT – the standard for HTML5, which also supports TV positioning and attributes

 DFXP – WC3 TTML profile



How do you choose?

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Captioning Techniques



Embedded captions

 Captions included in the compressed file



Sidecar

 Captions included as separate file and linked programmatically by player

Captioning Workflows



Live

 Broadcast source with captions  Create captions



VOD

 Source with captions  Other file

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Live Source with Captions



Most high end live encoders can pass through

608 or 708 source in necessary formats

Caption I/O iStreamPlanet’s Aventus platform.

Live – No Captions



Need stenographer to

create captions



Find a service

 Uvault – soup to nuts



Other providers

 CaptionMax

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VOD with Digital Captions



Most High end

VOD encoders

can input either

608 or 708 source

and convert to

necessary formats

 This is from encoding.com http://bit.ly/ozercap8

VOD With Embedded Captions

 Telestream

MacCaption/CaptionMake r

 Full featured programs with:

 Extensive import/export format support

 Caption creation editing interface and workflows

 Integration with editors and DVD authoring program

 Embed captions into multiple file formats

 Automatic time stamping to convert transcription into captions

 Some single-function freeware tools

 CCExtractor

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Captions in Other Sources

http://bit.ly/ozercap8 

Captions in optical

discs

 MacCaption/CaptionMak er 

Captions in transcript

 Automatic time stamping to convert transcription into captions

(Telestream)

VOD – Create Own Captions



Third Party Services

 Upload video

 Download caption files in a range of formats



Providers

 www.3playmedia.com

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Pricing from 3Play

Cheaper Alternatives



Upload video

to YouTube

 YouTube does speech to text  You cleanup  Download as .vtt, .srt or .sbv files

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Microsoft HTML Video Caption Maker

http://bit.ly/ozercap9  Input URL  Play file  Type captions  Export TTML or WebVTT  Copy and paste HTML code  (Dotsub has similar free tool)

Captioning Rules (NCAM)

1. Captions should be a verbatim representation of what is being said, although you may edit out unnecessary speech (um..., ah..., er..., etc.).

2. Each caption should be composed of one or two rows and should be positioned in the bottom center of the caption region. Avoid using three-row captions except when using a speaker identification.

3. If you can fit a caption on a single row rather than two, do so.

4. Caption what is spoken: if the speaker says "string" when he meant to say "spring", for example, caption it as such.

5. Don't correct grammar-if you hear it, caption it.

6. End punctuation (period, exclamation point, question mark) indicates the end of a caption, and the next sentence starts with a new caption.

7. Points (...) may be used to indicate a pause, an interruption or a suspension within the caption, or as end punctuation.

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Which Formats



Third party service provider, product or

plug-in

 Online video platforms

 OTS Players (like JW Player)  Cloud encoders

 Transcoders/media servers  Other encoders



Check which formats they require

Online Video Platforms (OVP)

 Check their requirements

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Off the Shelf Players

 Check their requirements

Cloud Encoders



We saw encoding.com



Here’s Zencoder

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Transcoder/Media Server



Wowza Media Server (more later)

Other Encoders



Telestream Vantage can add captions from

.scc and other inputs to a variety of outputs



Here’s Sorenson Squeeze



When working with an existing encoder,

check the supported formats and be sure to

supply

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Distribution Format



Flash



iOS



Android



HTML5



MSE/EME/DASH



CE devices

Flash



Supports multiple formats, TTML is preferred

(W3C Timed Text XML, formerly DFXP)

http://www.adobe.com/accessibilit y/products/flash/captions.html

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Supporting Mobile Devices



Two choices

 Support via apps – you can use any caption format you want

 Support via native browser or player  Must use specified format

iOS/HTTP Live Streaming

 HTTP Live Streaming supports closed captions within

streams

 When using stream segmenter, add CEA-608 closed captions to the MPEG-2 transport stream as specified in ATSC A/72.

 When using file segmenter, encapsulate your media in a QuickTime movie file and add a closed captions track ('clcp’)

 Live streaming also supports multiple subtitle and closed caption tracks in Web Video Text Tracks (WebVTT) format.

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iOS/HTTP Live Streaming

Android

 Android 4.1 was the first to support timed text tracks

 In band – text track within MP4 or 3GPP source

 Out of band – external text source – WebVTT is preferred format

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HTML5



Captions

 Can be embedded or sidecar  Sidecar – WebVTT format

 http://bit.ly/ozercap15

 Real world HTML5 caption support next slide, courtesy of JW Player

 It’s getting pretty good  http://bit.ly/ozercap16

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Formats



HTTP Dynamic Streaming (HDS)

 Supports CEA-708 embedded in F4F fragments  Embedded in data track as AMFO onCaptionInfo  Embed in H.264 SEI NALU

 Uses TTML Format 

Smooth Streaming

 TTML http://bit.ly/ozercap14

DASH



Two options;

 W3C TTML  SMPTE TT

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Formats



Two choices

 Prepare separate packages

 Transmux - Wowza Media Server (more later)

Caption Automation



For high volume use, consider tools with

 Batch operations via watch folder, GUI or

command line interface  Time tailor captions

 Adjusts captions when original materials are shortened or otherwise repurposed

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Caption Automation



Through acquisition of MacCaption/Caption

Maker, Telestream is a leader in this market

 Offers a free trial for MacCaption and CaptionMaker at

www.telestream.net/captioning.

 Or, to get a temp license to try out all the encoding decoding features, contact captioning team at

captionsales@telestream.net, ph: 800-977-6678.

