CAF: Working With Cmc Mixers

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Latest revision as of 09:15, 3 April 2014

Audio Mixers Definition

Audio mixers are used to mix audio from multiple call legs and provide mixed output to each call leg. At any time during a call flow the application can join call legs to one (or multiple) audio mixer.

TMedia concepts and density

Please read the following page for general information about TMedia Mixers: Audio Mixers

CTBCMCMixer class

An audio mixer is represented by an instance of the CTBCMCMixer class. Call legs (CTBCMCLeg) can be joined to this audio mixer as speakers, listeners, or both.

In addition to call legs joining/unjoining, the CTBCMCMixer class allows some media functions such as playing audio files to all listeners of the mixer, or recording all active speakers of the mixer.

Other member functions are available to retrieve (and change in some cases) the mixer attributes, and the way different call legs are joined to the mixer (speaker/listener)

It is important to note that this class is protocol-agnostic and can handle any type of supported call legs (e.g. SIP/VOIP, ISDN, SS7, Media only, etc).

Caveats

Do not confuse the base class CTBCMCMixer with the class CTBCAFMixer. The later is an implementation class specialized to be used by the ITBCAFCallFlow interface when dealing with multiple legs and mixers.

Command Flow for Mixer Actions in CAF

All actions requested on a mixer are executed asynchronously. For each action DoSomething() on a mixer, a corresponding OnSomethingResponse() event will be received on the mixer once Toolpack starts processing the command. If the OnSomethingResponse() function does not handle the response (the default implementation is empty) and the result of the action was a failure, the default error handling function OnMixerError() will be called. In some cases, when the action is completed, an event will be received on the mixer (OnSomethingDone() for example).

For example, to play an audio file on the mixer (heard by all legs listening to this mixer), one would call MixerPlayStream(). It would then almost immediately receive the OnMixerPlayStreamResponse() event indicating that Toolpack has received the command. At the same time this event is called, Toolpack will start configuring the resources to play on the mixer. Once the play has started, the user will receive an event OnMixerStreamPlayingStarted(), and when it finished playing (or failed to start), the user will receive an OnMixerStreamPlayingDone() event.

Mixer Creation

Creating a mixer is always done through the definition of a mixer attribute. The values entered in the mixer attribute will define how the mixer behaves, and will influence resource reservation.

Preparing Mixer Attributes

The class CTBCMC_MIXER_ATTRIBUTE defines available attributes to configure an audio mixer. Default parameters are provided for standard usage, though parameters may be changed to control the behavior more precisely. Example mixer attributes are:

SetReserveListenerSlot / IsReserveListenerSlot

Choose if a 'listener-only' slot must be reserved on this mixer (allocated even when no call leg is joined as listener-only). If disabled, the listener-only slot is added dynamically upon joining of first 'listener-only' leg (note that only one listener-only slot is required if more there are more than one listener-only legs).
Default is TBX_FALSE (no listener-only slot reservation).

SetNbReservedActiveSpeakerSlots / GetNbReservedActiveSpeakerSlots

Choose the number of speaker slots to reserve on this mixer. The mixer will always have minimum this number of speaker slots ready, though it can be more if joining more than that number of speaker call legs.
Default is 0 (no reserved active speaker slot).
Maximum is 12 active speakers (though there can be unlimited number of "inactive speakers", waiting voice activity detection to take the place of the oldest active speaker among the 12).

SetResizeDownTimer / GetResizeDownTimer

Choose the delay before reducing the size of a mixer (removing unnecessary IVR or TDM slots).
Smaller delay reduces MIPs usage faster, but increases the number of times mixers need to be re-sized, and thus increases CPU usage on the TMedia Unit.
Larger delay allows, for example, re-sizing the mixer only once if multiple users leave the conference (un-joined from the mixer) almost at the same time.
Default is 15,000 (15 seconds).

SetNbDominantSpeakers / GetNbDominantSpeakers

Choose the maximum number of active "dominant" speakers (maximum number of audio sources mixed together at a given time, based on loudest speakers).
Default is 3. Max is 12.

SetNoiseFloor / GetNoiseFloor

Choose the noise floor (for voice activity of inactive speakers, before they are considered active speakers).
Default is -30dbm. Min / max is -94dbm / 0dbm.

SetNoiseSuppressionLimit / GetNoiseSuppressionLimit

Choose the noise suppression limit (for removal of background noise from active speakers).
Default is 30dbm. Min / max is 0dbm / 95dbm.

SetTargetPower / GetTargetPower

Choose the target power for conference output. Conference output level will be adjusted (amplified up to GetGainLimit, dampened up to GetLossLimit) to match the target power.
Default is -5dbm. Min / max is -50dbm / 0dbm.

SetLossLimit / GetLossLimit, and SetGainLimit / GetGainLimit

Choose the loss limit / gain limit (limiting the audio level adjustments allowed from speaker legs to reach the target power)
Default loss limit is -10dbm. Min / max loss limit is -23dbm / 0dbm.
Default gain limit is 5dbm. Min / max gain limit is 0dbm / 23dbm.

SetReserveIvrSlot / IsReserveIvrSlot

Choose if a IVR slot must be reserved on this mixer (allocated even when not playing/recording). If disabled, IVR slot is add it dynamically when needed.
Default is TBX_FALSE (no IVR slot reservation).

SetRecordPlayback / IsRecordPlayback

Choose if mixer recording will "hear" the mixer audio playback or not.
Enabling this options will cause mixer to use 2 IVR slots.
Disabling this option will cause mixer to use 1 IVR slot for both play and record, but record won't include playback audio.
Default is TBX_FALSE (record don't include playback, use only 1 IVR slot)

Note: Please refer to header file tbcmc_mixer.hpp for a more complete documentation on all available mixer attributes.

Once a mixer is created, Toolpack will manage reservation of DSP resources on a TMedia, and will manage connecting legs to the mixer (listeners, or speakers). When call legs are joined or unjoined from the mixer, Toolpack will automatically re-size the DSP resource if appropriate (with a minimum size determined by the 'reserve' mixer attributes).

And thus, the application does not have to deal with resource management distribution among TMedia units.

For more information about capacity of TMedia units (in number of conference "slots"), please refer to this page: Audio Mixers -> Resource usage

The following code snippet shows how to build the attributes.

 PTRCTBCMC_MIXER_ATTRIBUTE ptrMixerAttribute;

 ptrMixerAttribute = tbnew CTBCMC_MIXER_ATTRIBUTE();

 ptrMixerAttribute->SetReserveIvrSlot( TBX_TRUE );
 ptrMixerAttribute->->SetReserveListenerSlot( TBX_FALSE );
 ptrMixerAttribute->SetNbReservedActiveSpeakerSlots( 3 );
 ptrMixerAttribute->SetNbDominantSpeakers( 3 );
 ptrMixerAttribute->SetNoiseFloor( TBCMC_VAD_NOISE_FLOOR_LEVEL_MINUS_30_DBM );
 ...

Creating the Mixer

Once the mixer attributes have been filled, creating the mixer in Toolpack is only a matter of creating a CTBCMCMixer object and calling MixerCreate() on it. At that moment a message is sent to Toolpack system to allocate the mixer on the hardware.

 pCallMixer = new CTBCMCMixer( 0 /* or MixerId from OnMixerSync() */, ptrMixerAttribute, this, &mLegMutex );
 pCallMixer ->MixerCreate();

Once the mixer has finished being allocated on hardware, the function OnMixerCreated() will be called.

Mixer Termination

Terminating a mixer is a 2 steps process:

Call MixerTerminate()
Ask for mixer object free upon OnMixerTerminated() callback function

When MixerTerminate() is called, the Toolpack framework will start destroying the mixer (including unjoining any call leg that was joined to it). Once the mixer hardware resources have been deallocated, Toolpack will call OnMixerTerminated(). Receiving that event means that the mixer no more exists in Toolpack, and the object can thus be freed. Any time after OnMixerTerminated() (or within that function), the application is responsible to call method FreeMixer(), which will eventually cause the mixer's ITBCMCFreeListener interface function Free to be called. The ITBCMCFreeListener to use can be specified either in the CTBCMCMixer constructor and by calling SetFreeListener(). The mixer can be it's own FreeListener, in which it just 'delete' itself. An application specific FreeListener can be used for cases where other action needs to be taken before the mixer is deleted. An example could be the case where the mixer object was allocated from a pool and it should be returned to that pool instead of being deleted.

In some situation, it is possible that mixer termination be initiated by Toolpack. This can happen in the event of sudden media resource unavailability on hardware, or if the application gets disconnected from Toolpack engine. In that cases, the callback OnMixerTerminated() is called. On reception of this event, the application should also acknowledge termination by calling FreeMixer().

Mixer Synchronization on Failover

When a Toolpack application is restarted, or when a standby application is activated, it goes through a synchronization phase with the Toolpack framework. During this phase, Toolpack informs the application of all the already allocated call legs, links and mixers:

Callback OnCallLegSync() lists all legs that were retrieved from Toolpack
Callback OnMixerSync() lists all mixers that were retrieved from Toolpack, along with list of legs joined to each mixer.
Callback OnLinkSync() lists all joined leg pairs that were retrieved from Toolpack
Callback OnMixerLinkSync() lists all legs joined to mixers, and mixers joined to mixers.

The course of action to take when receiving a leg or mixer synchronization event depends on the ability of the application to resynchronize or rebuild its own states.

A typical re-synchronization scenario would be similar to:

Application receives all OnCallLegSync() callbacks, for each a new object of type CTBCMCLeg is created
Application receives all OnMixerSync() callbacks, and for each a new object of type CTBCMCMixer is created.
Application receives all OnLinkSync() callbacks, and for each re-builds the association between the CTBCMCLeg by calling function SetJoined() of one of the legs.
Application receives all OnMixerLinkSync() callbacks, and for each re-builds the association between legs and mixers by calling function MixerSetJoined().
Any leg, link or mixer that the application does not wish to keep is destroyed (RefuseLeg, RefuseLink, RefuseMixer, or RefuseMixerLink)

When all legs, links and mixers have been synchronized, Toolpack sends the OnCmcLibReady() event indicating that active resources synchronization is complete. Event OnSyncDone() is also called on each re-synchronized leg, and OnMixerSyncDone() on each re-synchronized mixer.

@@ Line 3: / Line 3: @@
 At any time during a call flow the application can join call legs to one (or multiple) audio mixer.
+== TMedia concepts and density ==
+Please read the following page for general information about TMedia Mixers:
+[[AudioMixers|Audio Mixers]]
+== CTBCMCMixer class ==
 An audio mixer is represented by an instance of the CTBCMCMixer class.
-Call legs ([[http://docs.telcobridges.com/mediawiki/index.php/CAF:_Working_With_Cmc_Call_Legs CTBCMCLeg]]) can be joined to this audio mixer as talkers, listeners, or both.
+Call legs ([[CAF:_Working_With_Cmc_Call_Legs|CTBCMCLeg]]) can be joined to this audio mixer as speakers, listeners, or both.
-In addition to call legs joining/unjoining, the CTBCMCMixer class allows some media functions such as playing audio files or tones to all listeners of the mixer, or recording all active talkers of the mixer.
+In addition to call legs joining/unjoining, the CTBCMCMixer class allows some media functions such as playing audio files to all listeners of the mixer, or recording all active speakers of the mixer.
-Other member functions are available to retrieve (and change in some cases) the mixer attributes, and the way different call legs are joined to the mixer (talker/listener)
+Other member functions are available to retrieve (and change in some cases) the mixer attributes, and the way different call legs are joined to the mixer (speaker/listener)
 It is important to note that this class is protocol-agnostic and can handle any type of supported call legs (e.g. SIP/VOIP, [[ISDN]], SS7, Media only, etc).
-== todo ==
-- Max size of mixers
 ===== Caveats =====
 * Do not confuse the base class CTBCMCMixer with the class CTBCAFMixer. The later is an implementation class specialized to be used by the [https://docs.telcobridges.com/mediawiki/autodoc/class_t_b_c_a_f_1_1_i_t_b_c_a_f_call_flow.html ITBCAFCallFlow] interface when dealing with multiple legs and mixers.
 == Command Flow for Mixer Actions in CAF ==
-All actions requested on a mixer are executed asynchronously. For each action '''DoSomething()''' on a mixer,  a corresponding '''OnDoSomethingResponse()''' event will be received on the mixer once Toolpack starts processing the command. If the '''OnSomethingResponse()''' function does not handle the response (the default implementation is empty) and the result of the action was a failure, the default error handling function '''OnMixerError()''' will be called. In some cases, when the action is completed, an event will be received on the mixer ('''OnSomethingDone()''' for example).
+All actions requested on a mixer are executed asynchronously. For each action '''DoSomething()''' on a mixer,  a corresponding '''OnSomethingResponse()''' event will be received on the mixer once Toolpack starts processing the command. If the '''OnSomethingResponse()''' function does not handle the response (the default implementation is empty) and the result of the action was a failure, the default error handling function '''OnMixerError()''' will be called. In some cases, when the action is completed, an event will be received on the mixer ('''OnSomethingDone()''' for example).
-For example, to play a digit sequence, one would call '''MixerPlayDigit()'''. It would then almost immediately receive the '''OnMixerPlayDigitResponse()''' event indicating that Toolpack has received the command. At the same time this event is called, Toolpack will start playing the digits on the mixer. Once the digits play is completed, the user will receive an '''OnMixerDigitPlayingDone()''' event.
+For example, to play an audio file on the mixer (heard by all legs listening to this mixer), one would call '''MixerPlayStream()'''. It would then almost immediately receive the '''OnMixerPlayStreamResponse()''' event indicating that Toolpack has received the command. At the same time this event is called, Toolpack will start configuring the resources to play on the mixer. Once the play has started, the user will receive an event '''OnMixerStreamPlayingStarted()''', and when it finished playing (or failed to start), the user will receive an '''OnMixerStreamPlayingDone()''' event.
 == Mixer Creation ==
@@ Line 34: / Line 34: @@
 The class CTBCMC_MIXER_ATTRIBUTE defines available attributes to configure an audio mixer. Default parameters are provided for standard usage, though parameters may be changed to control the behavior more precisely.
 Example mixer attributes are:
-* Reserve IVR resource (else add it dynamically when needed)
+* '''SetReserveListenerSlot''' / '''IsReserveListenerSlot'''
-* Reserve talker slots (else add talker slots dynamically when needed)
+Choose if a 'listener-only' slot must be reserved on this mixer (allocated even when no call leg is joined as listener-only). If disabled, the listener-only slot is added dynamically upon joining of first 'listener-only' leg (note that only one listener-only slot is required if more there are more than one listener-only legs).<br>
-* Maximum number of active "loudest" speakers
+Default is TBX_FALSE (no listener-only slot reservation).
+* '''SetNbReservedActiveSpeakerSlots''' / '''GetNbReservedActiveSpeakerSlots'''
-Once a mixer is created, Toolpack will manage reservation of DSP resources on a TMedia, and will manage connecting legs to the mixer (listeners, or talkers). When call legs are joined or unjoined from the mixer, Toolpack will automatically re-size the DSP resource if appropriate (unless reserved talker resources have been requested, for example).
+Choose the number of speaker slots to reserve on this mixer. The mixer will always have minimum this number of speaker slots ready, though it can be more if joining more than that number of speaker call legs.<br>
-And thus, the application does not have to deal with resource management distribution among TMedia units, but only make sure that the total number of talkers (or reserved talker slots) does not exceed the DSP capacity of the TMedia units.
+Default is 0 (no reserved active speaker slot).<br>
+Maximum is 12 active speakers (though there can be unlimited number of "inactive speakers", waiting voice activity detection to take the place of the oldest active speaker among the 12).
+* '''SetResizeDownTimer''' / '''GetResizeDownTimer'''
+Choose the delay before reducing the size of a mixer (removing unnecessary IVR or TDM slots).<br>
+Smaller delay reduces MIPs usage faster, but increases the number of times mixers need to be re-sized, and thus increases CPU usage on the TMedia Unit.<br>
+Larger delay allows, for example, re-sizing the mixer only once if multiple users leave the conference (un-joined from the mixer) almost at the same time.<br>
+Default is 15,000 (15 seconds).
+* '''SetNbDominantSpeakers''' / '''GetNbDominantSpeakers'''
+Choose the maximum number of active "dominant" speakers (maximum number of audio sources mixed together at a given time, based on loudest speakers).<br>
+Default is 3. Max is 12.
+* '''SetNoiseFloor''' / '''GetNoiseFloor'''
+Choose the noise floor (for voice activity of inactive speakers, before they are considered active speakers).<br>
+Default is -30dbm. Min / max is -94dbm / 0dbm.
+* '''SetNoiseSuppressionLimit''' / '''GetNoiseSuppressionLimit'''
+Choose the noise suppression limit (for removal of background noise from active speakers).<br>
+Default is 30dbm. Min / max is 0dbm / 95dbm.
+* '''SetTargetPower''' / '''GetTargetPower'''
+Choose the target power for conference output. Conference output level will be adjusted (amplified up to GetGainLimit, dampened up to GetLossLimit) to match the target power.<br>
+Default is -5dbm. Min / max is -50dbm / 0dbm.
+* '''SetLossLimit''' / '''GetLossLimit''',  and '''SetGainLimit''' / '''GetGainLimit'''
+Choose the loss limit / gain limit (limiting the audio level adjustments allowed from speaker legs to reach the target power)<br>
+Default loss limit is -10dbm. Min / max loss limit is -23dbm / 0dbm.<br>
+Default gain limit is 5dbm. Min / max gain limit is 0dbm / 23dbm.
+* '''SetReserveIvrSlot''' / '''IsReserveIvrSlot'''
+Choose if a IVR slot must be reserved on this mixer (allocated even when not playing/recording). If disabled, IVR slot is add it dynamically when needed.<br>
+Default is TBX_FALSE (no IVR slot reservation).
+* '''SetRecordPlayback''' / '''IsRecordPlayback'''
+Choose if mixer recording will "hear" the mixer audio playback or not.<br>
+Enabling this options will cause mixer to use 2 IVR slots.<br>
+Disabling this option will cause mixer to use 1 IVR slot for both play and record, but record won't include playback audio.<br>
+Default is TBX_FALSE (record don't include playback, use only 1 IVR slot)
+<br>
+<br>
+<br>
+Note: Please refer to header file '''tbcmc_mixer.hpp''' for a more complete documentation on all available mixer attributes.
+<br>
+<br>
+Once a mixer is created, Toolpack will manage reservation of DSP resources on a TMedia, and will manage connecting legs to the mixer (listeners, or speakers). When call legs are joined or unjoined from the mixer, Toolpack will automatically re-size the DSP resource if appropriate (with a minimum size determined by the 'reserve' mixer attributes).<br>
+<br>
+And thus, the application does not have to deal with resource management distribution among TMedia units.<br>
+<br>
+<br>
+For more information about capacity of TMedia units (in number of conference "slots"), please refer to this page: [[AudioMixers#Resource_usage_of_mixers|Audio Mixers -> Resource usage]]
+<br>
+<br>
 The following code snippet shows how to build the attributes.
    PTRCTBCMC_MIXER_ATTRIBUTE ptrMixerAttribute;
@@ Line 46: / Line 89: @@
    ptrMixerAttribute = tbnew CTBCMC_MIXER_ATTRIBUTE();
-   ptrMixerAttribute->mfReserveIvr                  = TBX_TRUE;
+   ptrMixerAttribute->SetReserveIvrSlot( TBX_TRUE );
-   ptrMixerAttribute->mun32NbReservedActiveMembers  = 10;
+   ptrMixerAttribute->->SetReserveListenerSlot( TBX_FALSE );
+  ptrMixerAttribute->SetNbReservedActiveSpeakerSlots( 3 );
+  ptrMixerAttribute->SetNbDominantSpeakers( 3 );
+  ptrMixerAttribute->SetNoiseFloor( TBCMC_VAD_NOISE_FLOOR_LEVEL_MINUS_30_DBM );
+  ...
 === Creating the Mixer ===
-Once the mixer attributes have been filled, creating the mixer in Toolpack is only a matter of creating a CTBCMCMixer object and calling MixerCreate on it. At that moment a message is sent to Toolpack system to allocate the mixer on the hardware.
+Once the mixer attributes have been filled, creating the mixer in Toolpack is only a matter of creating a CTBCMCMixer object and calling '''MixerCreate()''' on it. At that moment a message is sent to Toolpack system to allocate the mixer on the hardware.
    pCallMixer = new CTBCMCMixer( 0 /* or MixerId from OnMixerSync() */, ptrMixerAttribute, this, &mLegMutex );
    pCallMixer ->MixerCreate();
-Once the mixer has finished being allocated on hardware, the function OnMixerCreated() will be called.
+Once the mixer has finished being allocated on hardware, the function '''OnMixerCreated()''' will be called.
@@ Line 61: / Line 108: @@
 Terminating a mixer is a 2 steps process:
-# Call MixerTerminate()
+# Call '''MixerTerminate()'''
-# Ask for mixer object free upon OnMixerTerminated() callback function
+# Ask for mixer object free upon '''OnMixerTerminated()''' callback function
-When '''MixerTerminate()''' is called, the Toolpack framework will start destroying the mixer (including unjoining any call leg that was joined to it). Once the mixer hardware resources have been deallocated, Toolpack will call '''OnMixerTerminated()'''. Receiving that event means that the mixer no more exists in Toolpack, and the object can thus be freed. Any time after '''OnMixerTerminated()''' (or within that function), the application is responsible to call method FreeMixer, which will eventually cause the mixer's [https://docs.telcobridges.com/mediawiki/autodoc/class_i_t_b_c_m_c_free_listener.html ITBCMCFreeListener] interface function 'Free' to be called. The ITBCMCFreeListener to use can be specified either in the CTBCMCMixer constructor and by calling SetFreeListener(). The mixer can be it's own ''FreeListener'', in which it just 'delete' itself. An application specific ''FreeListener'' can be used for cases where other action needs to be taken before the mixer is deleted. An example could be the case where the mixer object was allocated from a pool and it should be returned to that pool instead of being deleted.
+When '''MixerTerminate()''' is called, the Toolpack framework will start destroying the mixer (including unjoining any call leg that was joined to it). Once the mixer hardware resources have been deallocated, Toolpack will call '''OnMixerTerminated()'''. Receiving that event means that the mixer no more exists in Toolpack, and the object can thus be freed. Any time after '''OnMixerTerminated()''' (or within that function), the application is responsible to call method '''FreeMixer()''', which will eventually cause the mixer's [https://docs.telcobridges.com/mediawiki/autodoc/class_i_t_b_c_m_c_free_listener.html ITBCMCFreeListener] interface function '''Free''' to be called. The ITBCMCFreeListener to use can be specified either in the CTBCMCMixer constructor and by calling '''SetFreeListener()'''. The mixer can be it's own ''FreeListener'', in which it just 'delete' itself. An application specific ''FreeListener'' can be used for cases where other action needs to be taken before the mixer is deleted. An example could be the case where the mixer object was allocated from a pool and it should be returned to that pool instead of being deleted.
-In some situation, it is possible that mixer termination be initiated by Toolpack. This can happen in the event of sudden media resource unavailability on hardware. In that cases, the callback OnMixerTerminating is called. On reception of this event, the application should initiate termination as shown above (starting with MixerTerminate, as usual).
+In some situation, it is possible that mixer termination be initiated by Toolpack. This can happen in the event of sudden media resource unavailability on hardware, or if the application gets disconnected from Toolpack engine. In that cases, the callback '''OnMixerTerminated()''' is called. On reception of this event, the application should also acknowledge termination by calling '''FreeMixer()'''.
-In case of internal system error or major communication lost with the Toolpack engine, Toolpack would send the OnMixerTerminated() event directly without prior call to MixerTerminate from the application. This event indicates that the mixer already no more exist on the Toolpack side and the user should free its object by calling FreeMixer() on it.
 == Mixer Synchronization on Failover ==
 When a Toolpack application is restarted, or when a standby application is activated, it goes through a synchronization phase with the Toolpack framework. During this phase, Toolpack informs the application of all the already allocated call legs, links and mixers:
 * Callback '''OnCallLegSync()''' lists all legs that were retrieved from Toolpack
+* Callback '''OnMixerSync()''' lists all mixers that were retrieved from Toolpack, along with list of legs joined to each mixer.
 * Callback '''OnLinkSync()''' lists all joined leg pairs that were retrieved from Toolpack
-* Callback '''OnMixerSync()''' lists all mixers that were retrieved from Toolpack, along with list of legs joined to each mixer.
+* Callback '''OnMixerLinkSync()''' lists all legs joined to mixers, and mixers joined to mixers.
 The course of action to take when receiving a leg or mixer synchronization event depends on the ability of the application to resynchronize or rebuild its own states.
@@ Line 81: / Line 127: @@
 A typical re-synchronization scenario would be similar to:
 * Application receives all '''OnCallLegSync()''' callbacks, for each a new object of type CTBCMCLeg is created
+* Application receives all '''OnMixerSync()''' callbacks, and for each a new object of type CTBCMCMixer is created.
 * Application receives all '''OnLinkSync()''' callbacks, and for each re-builds the association between the CTBCMCLeg by calling function '''SetJoined()''' of one of the legs.
-* Application receives all '''OnMixerSync()''' callbacks, and for each a new object of type CTBCMCMixer is created. Context of each leg joined to this mixer is retrieved, and re-associated to the mixer using function '''MixerSetJoined()''' of the mixer
+* Application receives all '''OnMixerLinkSync()''' callbacks, and for each re-builds the association between legs and mixers by calling function '''MixerSetJoined()'''.
-* Any leg, link or mixer that the application does not wish to keep is destroyed ('''RefuseLeg''', '''RefuseLink''', '''RefuseMixer'''
+* Any leg, link or mixer that the application does not wish to keep is destroyed ('''RefuseLeg''', '''RefuseLink''', '''RefuseMixer''', or '''RefuseMixerLink''')
-Tip: The helper class CTBCAFCallLegResync has been created to simplify re-synchronizing legs. It can create and accumulate re-synchronized legs, and automatically destroy them when appropriate.
-* Call function AllocateCallLeg() for each synchronized leg
-* For legs that must not be destroyed after re-synchronization, call RemoveCallLeg() to remove them from this CTBCAFCallLegResync object. Application now has the ownership of the leg, and can pass it to '''SetJoined()''' or '''MixerSetJoined()'''.
-* Upon '''OnCmcLibReady()''', application must destroy CTBCAFCallLegResync. The destructor of this class will properly refuse all legs that have been created with AllocateCallLeg(), and not removed by RemoveCallLeg().
-You can refer to the code of the "SimpleCall" application for an example (search for variable mpCallLegResync).
 When all legs, links and mixers have been synchronized, Toolpack sends the '''OnCmcLibReady()''' event indicating that active resources synchronization is complete. Event '''OnSyncDone()''' is also called on each re-synchronized leg, and '''OnMixerSyncDone()''' on each re-synchronized mixer.

CAF: Working With Cmc Mixers

Latest revision as of 09:15, 3 April 2014

Contents

Audio Mixers Definition

TMedia concepts and density

CTBCMCMixer class

Caveats

Command Flow for Mixer Actions in CAF

Mixer Creation

Preparing Mixer Attributes

Creating the Mixer

Mixer Termination

Mixer Synchronization on Failover

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