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# ACP_COMMAND_UPDATE_XMA_READ_BUFFER

> ACP_COMMAND_UPDATE_XMA_READ_BUFFER

# ACP\_COMMAND\_UPDATE\_XMA\_READ\_BUFFER

Updates all the elements of a [SHAPE\_XMA\_CONTEXT](/reference/audio/shapexmacontext/structs/shape_xma_context) required to stream encoded data.

## Syntax

```cpp theme={null}
typedef struct ACP_COMMAND_UPDATE_XMA_READ_BUFFER {  
    UINT32 contextIndex;  
    UINT32 bufferIndex;  
    UINT32 bufferSize;  
    UINT32 changeSize;  
    UINT32 changeAddress;  
    APU_ADDRESS bufferAddress;  
} ACP_COMMAND_UPDATE_XMA_READ_BUFFER  
```

### Members

*contextIndex*\
Type: UINT32

Index of a context to be updated.

*bufferIndex*\
Type: UINT32

0 = left input buffer, 1 = right input buffer.

*bufferSize*\
Type: UINT32

Size of the buffer.

*changeSize*\
Type: UINT32

0 = keep the original size, 1 = use a new size.

*changeAddress*\
Type: UINT32

0 = keep the original address, 1 = use a new address.

*bufferAddress*\
Type: APU\_ADDRESS

Physical address of the buffer.

## Remarks

This structure is used by the `ACP_COMMAND_TYPE_UPDATE_XMA_READ_BUFFER` command. The read offset cannot be updated if the context is in use by SHAPE. See the [XMA utilities section of Overview of ACP](/build/console-features/audio/overviews/acp-overview#ID4EACAC) for associated commands.

## Requirements

**Header:** acphal.h

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

## See also

[ACP\_COMMAND\_TYPE](/reference/audio/acphal/enums/acp_command_type)\
[SubmitCommand](/reference/audio/acphal/interfaces/IAcpHal/methods/iacphal_submitcommand)\
[AcpHal](/reference/audio/acphal/acphal_members)


## Related topics

- [ACP_COMMAND_TYPE](/reference/audio/acphal/enums/acp_command_type.md)
- [AcpHal](/reference/audio/acphal/acphal_members.md)
- [ACP_COMMAND_INCREMENT_XMA_WRITE_BUFFER_OFFSET_READ](/reference/audio/acphal/structs/acp_command_increment_xma_write_buffer_offset_read.md)
- [ACP_COMMAND_UPDATE_XMA_CONTEXT](/reference/audio/acphal/structs/acp_command_update_xma_context.md)
- [ACP_COMMAND_UPDATE_XMA_CONTEXT_ENTRY](/reference/audio/acphal/structs/acp_command_update_xma_context_entry.md)