Ncast telepresenter reference manual – NCast Telepresenter M4 User Manual
Page 81
NCast Telepresenter Reference Manual
•
Available for download via our http interface
•
Uploaded automatically via the FTP upload service
Upon receipt of this file a program can easily extract the timing information of interest and create a web page
with playback start points of interest. For example, Quicktime uses the "STARTTIME" parameter:
http://www.apple.com/quicktime/tutorials/embed2.html
<embed src="sample.mp4" width="320" height="240" starttime="00:15:22.5">
After recording is finished and there is at least one subtitle, an .srt subtitle file is created which can be
downloaded from the web-page or HTTP interface. The .srt format is very simple, this example has two
subtitles:
1
00:00:20,000 --> 00:00:24,400
Subtitle 1
2
00:00:24,600 --> 00:00:27,800
Subtitle 2
The NCast Telepresenters support real-time caption or sub-title capture through use of serial commands
which define timings and durations of sub-title text. See the Telepresenter Serial Interface Reference Manual
for complete details.
7.6.2. Sub-titles using Quicktime and SMIL
Receivers/Decoders of the stream, whether using a desktop player (QuickTime, Windows Media Player, etc.)
or a Telepresenter system, must have the ability to turn on/off the captioning features; thus the term
“closed”. Unfortunately, there is no fully standardized mechanism for captioning across these technologies.
Each media player handles captions differently.
QuickTime does not currently support industry standard closed caption such as ISMA. QuickTime currently
supports closed captioning by including a text track alongside audio and video content. QuickTime currently
supports two main methods of introducing captions, through .QT.TXT and .SMIL files. This URL provides an
overview of the QuickTime text track:
The following sample .smil file launches a QuickTime player with a closed-caption text area:
<?xml version="1.0" encoding="UTF-8"?>
<smil xmlns:qt="http://www.apple.com/quicktime/resources/smilextensions"
xmlns="http://www.w3.org/TR/REC-smil" qt:time-slider="true">
<head>
<meta name="title" content="NCast Telepresenter M3 Commercial"/>
<meta name="author" content="VP Sales"/>
<meta name="copyright" content="NCast Corporation 2007"/>
<layout>
<root-layout height="285" width="330" background-color="black"/>
<region id="videoregion" left="5" height="240" width="320" top="5" background-
color="black"/>
<region id="textregion" left="5" height="40" width="320" top="245" background-
color="black"/>
</layout>
</head>
<body>
<par dur="0:03:14.10">
<video region="videoregion"
src="rtsp://www.ncast.com/archives/NCastCommercial320x240.mp4" dur="0:03:14.10"/>
<textstream region="textregion"
src="http://www.ncast.com/archives/NCastCommercial.en_US.qt.txt" dur="0:03:14.10"/>
</par>
</body>
NCast Corporation
Revision 2.2
Page 81