[asterisk-commits] oej: branch 1.6.0 r128418 - in /branches/1.6.0: ./ doc/realtimetext.txt
SVN commits to the Asterisk project
asterisk-commits at lists.digium.com
Sun Jul 6 05:19:07 CDT 2008
Author: oej
Date: Sun Jul 6 05:19:07 2008
New Revision: 128418
URL: http://svn.digium.com/view/asterisk?view=rev&rev=128418
Log:
The following patch with references to t140red removed, since it only exists
in trunk.
Merged revisions 128417 via svnmerge from
https://origsvn.digium.com/svn/asterisk/trunk
........
r128417 | oej | 2008-07-06 12:13:45 +0200 (Sön, 06 Jul 2008) | 3 lines
Adding documentation on the T.140 support in Asterisk. This is a function that we're
the reference implementation on now. :-)
........
Added:
branches/1.6.0/doc/realtimetext.txt
- copied, changed from r128417, trunk/doc/realtimetext.txt
Modified:
branches/1.6.0/ (props changed)
Propchange: branches/1.6.0/
------------------------------------------------------------------------------
Binary property 'trunk-merged' - no diff available.
Copied: branches/1.6.0/doc/realtimetext.txt (from r128417, trunk/doc/realtimetext.txt)
URL: http://svn.digium.com/view/asterisk/branches/1.6.0/doc/realtimetext.txt?view=diff&rev=128418&p1=trunk/doc/realtimetext.txt&r1=128417&p2=branches/1.6.0/doc/realtimetext.txt&r2=128418
==============================================================================
--- trunk/doc/realtimetext.txt (original)
+++ branches/1.6.0/doc/realtimetext.txt Sun Jul 6 05:19:07 2008
@@ -3,11 +3,6 @@
The SIP channel has support for real-time text conversation calls in Asterisk (T.140).
This is a way to perform text based conversations in combination with other media,
most often video. The text is sent character by character as a media stream.
-
-During a call sometimes there are losses of T.140 packets and a solution to that is to
-use redundancy in the media stream (RTP).
-See "http://en.wikipedia.org/wiki/Text_over_IP"http://en.wikipedia.org/wiki/Text_over_IP
-and RFC 5194 for more information.
The supported real-time text codec is t.140.
Real-time text redundancy support is now available in Asterisk.
@@ -26,26 +21,23 @@
allow=ulaw
allow = alaw
allow=t140
- allow=t140red
textsupport=yes
videosupport=yes ; needed for proper SDP handling even if only text and voice calls are handled
allow=h263 ; at least one video codec as H.261, H.263 or H.263+ is needed.
The codec settings may change, depending on your phones. The important settings here are to allow
-t140 and 140red and enable text support.
+t140 to enable text support.
General information about real-time text support in Asterisk
------------------------------------------------------------
With the configuration above, calls will be supported with any combination of real-time text,
audio and video.
-Text for both t140 and t140red is handled on channel and application level in Asterisk conveyed in
-Text frames, with the subtype "t140". Text is conveyed in such frames usually only containing one or
+Text (t140) is handled on channel and application level in Asterisk conveyed in
+text frames, with the subtype "t140". Text conveyed in such frames usually only contains one or
a few characters from the real-time text flow. The packetization interval is 300 ms, handled on lower
RTP level, and transmission redundancy level is 2, causing one original and two redundant transmissions
-of all text so that it is reliable even in high packet loss situations. Transmitting applications do not
-need to bother about the transmission interval. The t140red support handles any buffering needed during
-the packetization intervals.
+of all text so that it is reliable even in high packet loss situations.
Clients known to support text, audio/text or audio/video/text calls with Asterisk:
----------------------------------------------------------------------------------
@@ -74,7 +66,7 @@
Credits
-------
- Asterisk real-time text support is developed by AuPix
- - Asterisk real-time text redundancy support is developed by Omnitor
+ - Asterisk real-time text redundancy support (in trunk) is developed by Omnitor
The work with Asterisk real-time text redundancy was supported with funding from the National Institute
on Disability and Rehabilitation Research (NIDRR), U.S. Department of Education, under grant number
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