Text
Text
Interleaved text
RTP can be used to carry real-time text conversations, the contents use ITU-T Recommendation T.140 [RFC 4351]
Timed Text
The 3rd Generation Partnership Project (3GPP) has defined "timed text" as “time-lined, decorated text media format with defined storage in a 3GP file” [RFC 4396].
“Timed Text can be synchronized with audio/video contents and used in applications such as captioning, titling, and multimedia presentations.” [RFC 4396]
Martin Hörlin’s Master’s thesis ‘Voice Over IP for Textphones: An implementation of an Analog Telephone Adapter enabling Baudot textphones to use real-time text over Real-time Transport Protocol using open-source code and hardware solutions’ [Hörlin 2008]
Slide Notes
G. Hellstrom and P. Jones, “Real-Time Transport Protocol (RTP) Payload for Text Conversation Interleaved in an Audio Stream”, IETF, RFC 4351, January 2006 ftp://ftp.rfc-editor.org/in-notes/rfc4351.txt Links to an external site.
J. Rey and Y. Matsui, RTP Payload Format for 3rd Generation Partnership Project (3GPP) Timed Text, RFC 4396, February 2006 http://www.rfc-editor.org/rfc/rfc4396.txt Links to an external site.
[Hörlin 2008] Martin Hörlin, ‘Voice Over IP for Textphones : An implementation of an Analog Telephone Adapter enabling Baudot textphones to use real-time text over Real-time Transport Protocol using open-source code and hardware solutions’, Master’s thesis, KTH, Communication Systems, CoS, Stockholm, Sweden, 2008 [Online]. Available: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91889 Links to an external site.
Transcript
[slide511] Now I mentioned yesterday this idea of timeD text. There's also interleaved text, so we want to carry real-time text information. So our media now, instead of being audio packets, is actually bits of text. And so the result is, as the user's typing along, "hi," pause, pause, pause, "how are you?" And that pause in here was very important. As we said in comedy, right, and storytelling, the pauses are really important, the timing is everything. We can emulate that by now delivering the text with the same timing as the user typed it, just shifted in time because of the delay to get it there, but it will be played out in the same way. And Martin Hörlin, in his thesis, "Voice over IP for Telephones: An implementation of an Analog Telephoning Adapter using Baudot text telephones to use real-time text over the real-time transport protocol using open source code and hardware solutions", (one of the longest titles of a thesis ever), built a system like this for the organization in Sweden supporting hard-of-hearing users. And timed text is a really very, very fascinating area because text is not only used for hard-of-hearing, it is also used in things like captioning, titling. And oftentimes, you want the text to follow the video so that I can get the captioning in my choice of language with the video that I'm watching. It had better have the right temporal relationship.