[Live-devel] New LIVE555 version, changes the signature of "OnDemandServerMediaSubsession::seekStreamSource()"

[Ross Finlayson]

[This message is relevant only to people who have implemented their 
own subclass of "OnDemandServerMediaSubsession".  Everyone else can 
ignore this message.]

Those of you who have implemented your own subclass of 
"OnDemandServerMediaSubsession" (for implementing the unicast serving 
of a specific codec) should be aware that the latest version 
(2011.03.05) of the LIVE555 Streaming Media code changes the 
signature of the "seekStreamSource()" virtual function to add a 
"streamDuration" parameter.  This parameter, if >0.0, specifies a 
shorter finite duration for a stream (otherwise, the stream runs for 
its entire duration).  Subclasses of "OnDemandServerMediaSubsession" 
may (but are not required to) use this parameter to limit how much 
data is sent for the stream, before treating the stream as if had 
encountered EOF.

Our RTSP server implementation uses this to implement finite ranges 
specified in the "Range:" header in a "PLAY" request - e.g. "Range: 
npt=10-30", which specifies that the stream should run from the 10 
second point up to the 30 second point, but no longer.  (Previously, 
the server did not handle the end time (30, in this example) of a 
range; instead leaving it up to the client to 'TEARDOWN' the stream 
at the appropriate time.)

As with seeking, this functionality is implemented for some codecs, 
but not others.  It is currently implemented for MP3 audio, WAV 
audio, and DV video.  (Support for Transport Stream data will be 
added shortly.)
-- 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/