AudioMixers

Revision as of 14:52, 17 January 2012

Toolpack audio mixers

A mixer is used to mix the audio of multiple sources (call legs, playing audio file, tone generation...)

Typical usage of audio mixers

Audio mixers can be used, among other things, to:

• Build conferences
• Play background music to a conversation
• Record both sides of the conversation into a single recorded file.

Joining audio source to a mixer

There are 2 ways to join a mixer:

• Join as a listener only
• Join as a talker. Talkers can be active / or inactive (inactive speakers are not mixed, but monitored for voice activity)

Maximum call legs per mixer

The mixer has the following limits on the number of talkers:

• The mixer can have any number of talkers (up to maximum TMedia system capacity of about 32,000 call legs)
• Among these talkers, up to 10 will be considered as "active" (the 10 from which audio was received the most recently)
• Among these 10 active talkers, the audio from loudest N talkers will be mixed (other will be ignored)

The mixer has the following limits on the number of listeners:

• The mixer can have any number of listeners (up to maximum TMedia system capacity of about 32,000 call legs)

Resource usage of mixers

• An active talker uses one mixer slot (up to 10 per conference)
• All non-active talkers use one mixer slot (no per-conference limit)
• All listeners share one mixer slot
• IVR (playing file, playing tone, recording file) use one mixer slot

The maximum "slots" that a mixer can use is thus 12 (even when it has up to about 32,000 non-active talkers or listeners)

Note: Recording or playing files to individual call legs will not be done by the mixer itself, and will thus require separate DSP resources in addition to the mixer itself.

A Tmedia Unit has a density of about 512 mixer slots per DSP, and can have up to 4 DSPs.