1# metadata_output.h
2
3
4## Overview
5
6The **metadata_output.h** file declares the metadata output concepts.
7
8**Library**: libohcamera.so
9
10**File to include**: <ohcamera/metadata_output.h>
11
12**System capability**: SystemCapability.Multimedia.Camera.Core
13
14**Since**: 11
15
16**Related module**: [OH_Camera](_o_h___camera.md)
17
18
19## Summary
20
21
22### Structs
23
24| Name| Description|
25| -------- | -------- |
26| struct  [MetadataOutput_Callbacks](_metadata_output___callbacks.md) | Describes the callbacks related to metadata output. |
27
28
29### Types
30
31| Name| Description|
32| -------- | -------- |
33| typedef struct [Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) [Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) | Defines a struct for the metadata output object. |
34| typedef void(\* [OH_MetadataOutput_OnMetadataObjectAvailable](_o_h___camera.md#oh_metadataoutput_onmetadataobjectavailable)) ([Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) \*metadataOutput, [Camera_MetadataObject](_camera___metadata_object.md) \*metadataObject, uint32_t size) | Defines the pointer to the callback defined in the [MetadataOutput_Callbacks](_metadata_output___callbacks.md) struct and used to report metadata output data. |
35| typedef void(\* [OH_MetadataOutput_OnError](_o_h___camera.md#oh_metadataoutput_onerror)) ([Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) \*metadataOutput, [Camera_ErrorCode](_o_h___camera.md#camera_errorcode) errorCode) | Defines the pointer to the callback defined in the [MetadataOutput_Callbacks](_metadata_output___callbacks.md) struct and used to report metadata output errors. |
36| typedef struct [MetadataOutput_Callbacks](_metadata_output___callbacks.md) [MetadataOutput_Callbacks](_o_h___camera.md#metadataoutput_callbacks) | Defines a struct for the callback functions of metadata output. |
37
38
39### Functions
40
41| Name| Description|
42| -------- | -------- |
43| [Camera_ErrorCode](_o_h___camera.md#camera_errorcode) [OH_MetadataOutput_RegisterCallback](_o_h___camera.md#oh_metadataoutput_registercallback) ([Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) \*metadataOutput, [MetadataOutput_Callbacks](_metadata_output___callbacks.md) \*callback) | Registers a callback to listen for metadata output events. |
44| [Camera_ErrorCode](_o_h___camera.md#camera_errorcode) [OH_MetadataOutput_UnregisterCallback](_o_h___camera.md#oh_metadataoutput_unregistercallback) ([Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) \*metadataOutput, [MetadataOutput_Callbacks](_metadata_output___callbacks.md) \*callback) | Unregisters the callback used to listen for metadata output events. |
45| [Camera_ErrorCode](_o_h___camera.md#camera_errorcode) [OH_MetadataOutput_Start](_o_h___camera.md#oh_metadataoutput_start) ([Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) \*metadataOutput) | Starts metadata output. |
46| [Camera_ErrorCode](_o_h___camera.md#camera_errorcode) [OH_MetadataOutput_Stop](_o_h___camera.md#oh_metadataoutput_stop) ([Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) \*metadataOutput) | Stops metadata output. |
47| [Camera_ErrorCode](_o_h___camera.md#camera_errorcode) [OH_MetadataOutput_Release](_o_h___camera.md#oh_metadataoutput_release) ([Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) \*metadataOutput) | Releases a **MetadataOutput** instance. |
48