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**System capability**: SystemCapability.Multimedia.Camera.Core 11 12**Since**: 11 13 14**Related module**: [OH_Camera](_o_h___camera.md) 15 16 17## Summary 18 19 20### Structs 21 22| Name| Description| 23| -------- | -------- | 24| [MetadataOutput_Callbacks](_metadata_output___callbacks.md) | Defines the callback functions of metadata output.| 25 26 27### Types 28 29| Name| Description| 30| -------- | -------- | 31| [Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) | Defines the metadata output object.| 32| [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.| 33| [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.| 34| [MetadataOutput_Callbacks](_o_h___camera.md#metadataoutput_callbacks) | Defines the callback functions of metadata output.| 35 36 37### Functions 38 39| Name| Description| 40| -------- | -------- | 41| [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.| 42| [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.| 43| [OH_MetadataOutput_Start](_o_h___camera.md#oh_metadataoutput_start) ([Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) \*metadataOutput) | Starts metadata output.| 44| [OH_MetadataOutput_Stop](_o_h___camera.md#oh_metadataoutput_stop) ([Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) \*metadataOutput) | Stops metadata output.| 45| [OH_MetadataOutput_Release](_o_h___camera.md#oh_metadataoutput_release) ([Camera_MetadataOutput](_o_h___camera.md#camera_metadataoutput) \*metadataOutput) | Releases a **MetadataOutput** instance.| 46