[Live-devel] SAP announcements and the live555 library in VLC (multiple media ports please)

[John Blyth]

Hi all,

the live555 library is used by VLC.  VLC can decode SAP announcements
to make it easy for end users to access playlists via SAP announce and
it appears that the live555 library is used to decode the SAP
announcements. But VLC will not decode properly formed SAP
announcements where there is more than one media line. It appears that
this is a function of the live555 library and it changed about version
1.0.5 of VLC when there used to be a workaround before this version.

For those of us who use RTSP streams with multiple media (aka QTSS /
DSS) with in a multicast enabled network, getting this to work
properly would be a great benefit.  SAP/SDP files can have one
connection entry for the whole file with multiple media lines/entries,
or an individual connection entry with each media line. Both of these
options are compliant with the RFC for SAP/SDP.

Now I assume the live555 library was written with the assumption that
the main media being used was multiplexed MPEG-TS with one port set
only, and so one connection entry; one media file is all that it
requires.  But for live (IP / darwin / QT / flash) streaming it is
typical to have two media ports, one for video, one for audio within
the one connection.

A plea to the live555 developers (I am making an assumption based on a
response from the VLC developer{s}) that it is the live555 library
that is the cause of this problem) - can the live555 library be
adjusted so that it can successfully handle SAP/SDP files for the
wider range of live broadcast media that use multiple media ports.

See this entry here for the VLC discussion

http://forum.videolan.org/viewtopic.php?f=2&t=81370&p=290102#p290102

thankyou

JB