How to: Group Audio Methods as an Operation Set

Article
01/07/2021

This topic shows you how you can group together XAudio2 methods so they take effect at the same time.

To group audio methods as an operation set

Declare a global operation set counter.

The operation set counter ensures that each operation set is unique.
```
UINT32 OperationSetCounter = 0;
```
Increment the global counter.

Each time you submit a new operation set, the global counter should increment to ensure each set is unique.
```
UINT32 OperationID = UINT32(InterlockedIncrement(LPLONG(&OperationSetCounter)));
```
Group the method calls by setting their operation set parameters.
Set the operation set parameters to the current value of the global counter.

In this case, four calls to IXAudio2SourceVoice::Start are grouped as one operation set. Grouping the calls causes all four of the sounds to start at exactly the same time.
```
hr = pSFXSourceVoice1->Start( 0, OperationID );
hr = pSFXSourceVoice2->Start( 0, OperationID );
hr = pSFXSourceVoice3->Start( 0, OperationID );
hr = pSFXSourceVoice4->Start( 0, OperationID );
```
Start the operation set.

After you call all the methods in the set, start the set by calling IXAudio2::CommitChanges with the current value of the global counter.
```
pXAudio2->CommitChanges(OperationID);
```

Operation Sets
XAudio2 Programming Guide
XAudio2 Operation Sets