> ## Documentation Index
> Fetch the complete documentation index at: https://devdocs.xbox.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ACP_COMMAND_UPDATE_PCM_CONTEXT

> ACP_COMMAND_UPDATE_PCM_CONTEXT

# ACP\_COMMAND\_UPDATE\_PCM\_CONTEXT

更新 PCM 上下文的命令。

## 语法

```cpp theme={null}
typedef struct ACP_COMMAND_UPDATE_PCM_CONTEXT {  
    UINT32 contextIndex;  
    UINT32 updateMask;  
    APU_ADDRESS contextData;  
} ACP_COMMAND_UPDATE_PCM_CONTEXT  
```

### 成员

*contextIndex*\
类型:UINT32

要更新的上下文的索引。

*updateMask*\
类型:UINT32

一个或多个更新标志。

| 标志                                              | 值          |
| ----------------------------------------------- | ---------- |
| SHAPE\_PCM\_UPDATE\_BUFFER\_START               | 0x00000001 |
| SHAPE\_PCM\_UPDATE\_BUFFER\_LENGTH              | 0x00000002 |
| SHAPE\_PCM\_UPDATE\_FORMAT                      | 0x00000004 |
| SHAPE\_PCM\_UPDATE\_MODE                        | 0x00000008 |
| SHAPE\_PCM\_UPDATE\_READ\_POINTER               | 0x00000010 |
| SHAPE\_PCM\_UPDATE\_LOOP\_START\_WRITE\_POINTER | 0x00000020 |
| SHAPE\_PCM\_UPDATE\_LOOP\_END                   | 0x00000040 |
| SHAPE\_PCM\_UPDATE\_LOOP\_COUNT                 | 0x00000080 |
| SHAPE\_PCM\_UPDATE\_FULL                        | 0x00000100 |
| SHAPE\_PCM\_UPDATE\_MASK                        | 0x000001ff |

*contextData*\
类型:APU\_ADDRESS

要更新的上下文数据的物理地址。请参阅 [SHAPE\_PCM\_CONTEXT](/reference/audio/shapepcmcontext/structs/shape_pcm_context) 结构体。

## 备注

此结构体由 `ACP_COMMAND_TYPE_UPDATE_PCM_CONTEXT` 命令使用。请仅在每个音频帧内使用该命令更新少量上下文;更新大量上下文的效率不高。有关更多详细信息,请参阅 [ACP 概述中的"渲染音频"部分](/build/console-features/audio/overviews/acp-overview#ID4E6C)。

## 要求

**头文件:** acphal.h

**支持的平台:** XBOX One 系列主机和 XBOX Series 主机

## 概念文档

* [ACP 概述](/build/console-features/audio/overviews/acp-overview)

## 另请参阅

[SHAPE\_PCM\_CONTEXT](/reference/audio/shapepcmcontext/structs/shape_pcm_context)\
[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 概述](/zh-CN/build/console-features/audio/overviews/acp-overview.md)
- [ACP_COMMAND_TYPE](/zh-CN/reference/audio/acphal/enums/acp_command_type.md)
- [AcpHal](/zh-CN/reference/audio/acphal/acphal_members.md)
- [ACP_COMMAND_LOAD_SHAPE_FLOWGRAPH](/zh-CN/reference/audio/acphal/structs/acp_command_load_shape_flowgraph.md)
- [ACP_COMMAND_UPDATE_PCM_CONTEXT_ENTRY](/zh-CN/reference/audio/acphal/structs/acp_command_update_pcm_context_entry.md)