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# ACP_COMMAND_UPDATE_PCM_CONTEXT_ENTRY

> ACP_COMMAND_UPDATE_PCM_CONTEXT_ENTRY

Entry for updating a SHAPE\_PCM\_CONTEXT.

## Syntax

```cpp theme={null}
typedef struct ACP_COMMAND_UPDATE_PCM_CONTEXT_ENTRY {  
    UINT32 contextIndex;  
    UINT32 loopStartWritePointer;  
} ACP_COMMAND_UPDATE_PCM_CONTEXT_ENTRY  
```

### Members

*contextIndex*\
Type: UINT32

Index in the range of 0 to ACP\_MAX\_NUM\_PCM\_CONTEXTS.

*loopStartWritePointer*\
Type: UINT32

Replaces the existing value of SHAPE\_PCM\_CONTEXT::loopStartWritePointer.

## Remarks

This structure is used by `ACP_COMMAND_UPDATE_CONTEXTS` and `ACP_COMMAND_UPDATE_ALL_CONTEXTS` commands to update a single PCM context. Use the command to update only a small number of contexts per audio frame; updating a large number of contexts is not efficient. See the [Rendering audio section of Overview of ACP](https://docs.xbox.com/build/console-features/audio/overviews/acp-overview.md#ID4E6C) for more detail.

## Requirements

**Header:** acphal.h

**Supported platforms:** XBOX One family consoles and XBOX Series consoles

## See also

[ACP\_COMMAND\_TYPE](https://docs.xbox.com/reference/audio/acphal/enums/acp_command_type.md)\
[SubmitCommand](https://docs.xbox.com/reference/audio/acphal/interfaces/IAcpHal/methods/iacphal_submitcommand.md)\
[AcpHal](https://docs.xbox.com/reference/audio/acphal/acphal_members.md)


## Related topics

- [AcpHal](https://docs.xbox.com/reference/audio/acphal/acphal_members.md)
- [ACP_COMMAND_UPDATE_CONTEXTS](https://docs.xbox.com/reference/audio/acphal/structs/acp_command_update_contexts.md)
- [ACP_COMMAND_UPDATE_XMA_CONTEXT_ENTRY](https://docs.xbox.com/reference/audio/acphal/structs/acp_command_update_xma_context_entry.md)
- [ACP_COMMAND_UPDATE_ALL_CONTEXTS](https://docs.xbox.com/reference/audio/acphal/structs/acp_command_update_all_contexts.md)
- [ACP_COMMAND_UPDATE_PCM_CONTEXT](https://docs.xbox.com/reference/audio/acphal/structs/acp_command_update_pcm_context.md)