CaptionKeeper
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Transcript CaptionKeeper
access.wgbh.org
CaptionKeeper
Bradley Botkin
Director, Technology & Systems Development
WGBH / NCAM
National Center for Accessible Media
www.captionkeeper.org
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What Is It?
CaptionKeeper is a production tool that transcodes live text data to webstreaming formats.
Use-cases:
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Live-events streamed to the web with closed captions
Repurpose captioned television content for live or on-demand streaming
Digitize captioned archival material
Inputs include:
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line-21 (closed caption) data from NTSC video
live stenocaption / court reporter (Ascii) data
Outputs include:
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QuickTime (QTtext) (on-demand only)
RealPlayer (RealText) (live or on-demand)
Windows Media Player (SAMI) (live or on-demand)
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Analog Television Closed Captioning
What is
this rolling
black line?
Line-21
Data
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A two-slide overview of web captioning (1): Timed-Text Formats
[Windows Media Player]
[SMIL]
<SYNC Start=“7460"><P Class ="Captions">
Our nearest star, the sun,<br/>
has formed such a dimple</P>
</SYNC>
<smil>
<head>
<!-- define boxes here -->
<root-layout height="200" width="250"/>
<region id="vreg" top="5" left="5" height="120“ width="250"/>
<region id="treg" top="125" left="5" height="50" width="250"/>
[Real Player]
<time begin="00:07.4"/> <clear/>
Our nearest star, the sun,<br/>
has formed such a dimple
[QuickTime Player]
{justify: left}
[00:00:07.46]
Our nearest star, the sun,
has formed such a dimple
</layout>
</head>
<!-- specify source files here -->
<body>
<par>
<video src="kennedy-interview-28.rm" region="videoregion"/>
<textstream src="kennedy-interview.rt" region="textregion"/>
</par>
</body>
</smil>
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A two-slide overview of web captioning (2):
QT
Broadcaster
Real
Encoder
Darwin Server
SMIL
Presentation
(video/audio)
(QTtext, on-demand)
Real Server
(video/audio)
(RealText, live/on-demand)
Windows Media
Encoder
Web streaming flowchart
SMIL
Presentation
QuickTime Player
Enable/disable text track
RealPlayer
Enable/disable captions
IIS Server (video/audio)
Windows Media Player
(SAMI, on-demand)
Enable/disable captions
(SAMI, live)
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Main Screen
-Select an input (only one)
-Select outputs. All three outputs are supported simultaneously.
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Input: Serial Line-21
For serial data recovery device
-Match parameters (baud, data bits, parity, etc.)
For Adrienne USB device:
- Just plug it in and go
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Output: Real
Real output control is simple.
- Connect to the RealServer
- Set up layout and text parameters
- Webcast
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Output: Real Options
Real output options include:
- IP settings for RealServer connectivity
- Window/Text attributes for font, etc.
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Output: Windows Media
Windows Media output control is simple.
- Connect to the Windows Media Encoder
- Set up layout and text parameters
- Webcast
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Output: Windows Options
Windows Media output options include:
- IP settings for WME connectivity
- Window/Text attributes for font, etc.
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Windows Media Encoder: Remote
When Windows Media Encoder (WME) runs on a
remote machine, run CKwme on that remote machine
to provide connectivity for CaptionKeeper.
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Sample Output
The sample below is CaptionKeeper output to a RealServer, played back in
RealPlayer. We’re not capturing video here, there’s just a RealText stream which
follows the closed captions, with one line of text transmitted as the line rolls up on
the TV.
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Signal Pathways
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Hardware Requirements
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Wintel-style computer
Serial (RS-232) port or USB port for input
Ethernet port for output
Source of closed caption data
(Typically a closed caption data recovery decoder,
e.g. EEG DE-241-DR or Adrienne USB21VL/RDR or other line-21 device.)
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Further Information
CaptionKeeper:
- General: www.captionkeeper.org
- FAQ: (off the CaptionKeeper page)
- Email: [email protected]
Rich Media Resources:
- http://ncam.wgbh.org/richmedia/
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