While a recording
is in progress, the session is monitored by a third-party streaming-media
player or by the built-in media player in MediaSense.
To monitor a call
from a third-party streaming-media player, a client must specify a real-time
streaming protocol (RTSP) URI that can supply HTTP-BASIC credentials and can
handle a 302 redirect. The client can obtain the URI either by querying the
metadata or by capturing session events.
an HTTP query API that allows suitably authenticated clients to search for
recorded sessions based on many criteria, including whether the recording is
active. Alternatively, a client may subscribe for session events and receive
MediaSense Symmetric Web Service (SWS) events whenever a recording is started
(among other conditions). In either case, the body passed to the client
includes a large amount of metadata about the recording, including the RTSP URI
to be used for streaming.
streaming-media players that Cisco has tested for MediaSense are VLC and
RealPlayer. Each of these players has advantages and disadvantages that should
be taken into account when selecting which one to use.
are usually made up of two audio tracks. MediaSense receives and stores them
that way and does not currently support real-time mixing.
VLC can only play
one track at a time. The user can alternate between tracks but cannot hear both
simultaneously. VLC is open source and is easy to embed into a browser page.
play the two streams as stereo (one stream in each ear) but its buffering
algorithms for slow connections sometimes results in misleading periods of
silence for the listener. People are more or less used to such delays when
playing recorded music or podcasts, but call monitoring is expected to be real
time and significant buffering delays are inappropriate for that purpose.
None of these
players can render AAC-LD, g.729 or g.722 audio. A custom application must be
created in order to monitor or play streams in those forms.
built-in media player is accessed by a built-in Search and Play application.
This player covers more codecs and can play both streams simultaneously, but it
does not support the AAC-LD audio codec, or in some cases, the g.729 codec.
These features apply to both playback of recorded calls and monitoring of
Only calls that
are being recorded are available to be monitored. Customers who require live
monitoring of unrecorded calls, or who cannot accept these other restrictions,
may want to consider Unified Communications Manager's Silent Monitoring