1# media_asset_manager_capi.h 2 3## Overview 4 5The file declares the APIs of the media asset manager. You can use the functions to request media assets in the media library. 6 7**Library**: libmedia_asset_manager.so 8 9**File to include**: <multimedia/media_library/media_asset_manager_capi.h> 10 11**System capability**: SystemCapability.FileManagement.PhotoAccessHelper.Core 12 13**Since**: 12 14 15**Related module**: [MediaAssetManager](capi-mediaassetmanager.md) 16 17## Summary 18 19### Functions 20 21| Name| Description| 22| -- | -- | 23| [OH_MediaAssetManager* OH_MediaAssetManager_Create(void)](#oh_mediaassetmanager_create) | Creates an OH_MediaAssetManager instance.| 24| [MediaLibrary_RequestId OH_MediaAssetManager_RequestImageForPath(OH_MediaAssetManager* manager, const char* uri,MediaLibrary_RequestOptions requestOptions, const char* destPath, OH_MediaLibrary_OnDataPrepared callback)](#oh_mediaassetmanager_requestimageforpath) | Requests an image in the specified directory.| 25| [MediaLibrary_RequestId OH_MediaAssetManager_RequestVideoForPath(OH_MediaAssetManager* manager, const char* uri,MediaLibrary_RequestOptions requestOptions, const char* destPath, OH_MediaLibrary_OnDataPrepared callback)](#oh_mediaassetmanager_requestvideoforpath) | Requests a video in the specified directory.| 26| [bool OH_MediaAssetManager_CancelRequest(OH_MediaAssetManager* manager, const MediaLibrary_RequestId requestId)](#oh_mediaassetmanager_cancelrequest) | Cancels a request based on the request ID.| 27| [MediaLibrary_ErrorCode OH_MediaAssetManager_RequestMovingPhoto(OH_MediaAssetManager* manager,OH_MediaAsset* mediaAsset, MediaLibrary_RequestOptions requestOptions, MediaLibrary_RequestId* requestId,OH_MediaLibrary_OnMovingPhotoDataPrepared callback)](#oh_mediaassetmanager_requestmovingphoto) | Requests a moving photo based on different policies.| 28| [MediaLibrary_ErrorCode OH_MediaAssetManager_RequestImage(OH_MediaAssetManager* manager, OH_MediaAsset* mediaAsset,MediaLibrary_RequestOptions requestOptions, MediaLibrary_RequestId* requestId,OH_MediaLibrary_OnImageDataPrepared callback)](#oh_mediaassetmanager_requestimage) | Requests an image based on different policies.| 29| [MediaLibrary_ErrorCode OH_MediaAssetManager_Release(OH_MediaAssetManager* manager)](#oh_mediaassetmanager_release) | Releases an [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md) instance.| 30 31## Function Description 32 33### OH_MediaAssetManager_Create() 34 35``` 36OH_MediaAssetManager* OH_MediaAssetManager_Create(void) 37``` 38 39**Description** 40 41Creates an OH_MediaAssetManager instance. 42 43**Since**: 12 44 45**Return value** 46 47| Type| Description| 48| -- | -- | 49| [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md)* | Pointer to the OH_MediaAssetManager instance created.| 50 51### OH_MediaAssetManager_RequestImageForPath() 52 53``` 54MediaLibrary_RequestId OH_MediaAssetManager_RequestImageForPath(OH_MediaAssetManager* manager, const char* uri,MediaLibrary_RequestOptions requestOptions, const char* destPath, OH_MediaLibrary_OnDataPrepared callback) 55``` 56 57**Description** 58 59Requests an image in the specified directory. 60 61**Required permissions**: ohos.permission.READ_IMAGEVIDEO 62 63**Since**: 12 64 65 66**Parameters** 67 68| Parameter| Description| 69| -- | -- | 70| [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md)* manager | Pointer to an OH_MediaAssetManager instance.| 71| const char* uri | Pointer to the URI of the requested image.| 72| [MediaLibrary_RequestOptions](capi-mediaassetmanager-medialibrary-requestoptions.md) requestOptions | Options related to the media asset quality and delivery mode.| 73| const char* destPath | Pointer to the destination directory of the requested image.| 74| [OH_MediaLibrary_OnDataPrepared](capi-media-asset-base-capi-h.md#oh_medialibrary_ondataprepared) callback | Callback to be invoked when the requested image is ready.| 75 76**Return value** 77 78| Type| Description| 79| -- | -- | 80| [MediaLibrary_RequestId](capi-mediaassetmanager-medialibrary-requestid.md) | Request ID.| 81 82### OH_MediaAssetManager_RequestVideoForPath() 83 84``` 85MediaLibrary_RequestId OH_MediaAssetManager_RequestVideoForPath(OH_MediaAssetManager* manager, const char* uri,MediaLibrary_RequestOptions requestOptions, const char* destPath, OH_MediaLibrary_OnDataPrepared callback) 86``` 87 88**Description** 89 90Requests a video in the specified directory. 91 92**Required permissions**: ohos.permission.READ_IMAGEVIDEO 93 94**Since**: 12 95 96 97**Parameters** 98 99| Parameter| Description| 100| -- | -- | 101| [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md)* manager | Pointer to an OH_MediaAssetManager instance.| 102| const char* uri | Pointer to the URI of the requested video.| 103| [MediaLibrary_RequestOptions](capi-mediaassetmanager-medialibrary-requestoptions.md) requestOptions | Options related to the media asset quality and delivery mode.| 104| const char* destPath | Pointer to the destination directory of the requested video.| 105| [OH_MediaLibrary_OnDataPrepared](capi-media-asset-base-capi-h.md#oh_medialibrary_ondataprepared) callback | Callback to be invoked when the requested video is ready.| 106 107**Return value** 108 109| Type| Description| 110| -- | -- | 111| [MediaLibrary_RequestId](capi-mediaassetmanager-medialibrary-requestid.md) | Request ID.| 112 113### OH_MediaAssetManager_CancelRequest() 114 115``` 116bool OH_MediaAssetManager_CancelRequest(OH_MediaAssetManager* manager, const MediaLibrary_RequestId requestId) 117``` 118 119**Description** 120 121Cancels a request based on the request ID. 122 123**Required permissions**: ohos.permission.READ_IMAGEVIDEO 124 125**Since**: 12 126 127 128**Parameters** 129 130| Parameter| Description| 131| -- | -- | 132| [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md)* manager | Pointer to an OH_MediaAssetManager instance.| 133| const [MediaLibrary_RequestId](capi-mediaassetmanager-medialibrary-requestid.md) requestId | ID of the request to cancel.| 134 135**Return value** 136 137| Type| Description| 138| -- | -- | 139| bool | Operation result. The value **true** is returned if the request is successfully canceled, and **false** is returned otherwise.| 140 141### OH_MediaAssetManager_RequestMovingPhoto() 142 143``` 144MediaLibrary_ErrorCode OH_MediaAssetManager_RequestMovingPhoto(OH_MediaAssetManager* manager,OH_MediaAsset* mediaAsset, MediaLibrary_RequestOptions requestOptions, MediaLibrary_RequestId* requestId,OH_MediaLibrary_OnMovingPhotoDataPrepared callback) 145``` 146 147**Description** 148 149Requests a moving photo based on different policies. 150 151**Required permissions**: ohos.permission.READ_IMAGEVIDEO 152 153**Since**: 13 154 155 156**Parameters** 157 158| Parameter| Description| 159| -- | -- | 160| [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md)* manager | Pointer to an [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md) instance.| 161| [OH_MediaAsset](capi-mediaassetmanager-oh-mediaasset.md)* mediaAsset | Pointer to the [OH_MediaAsset](capi-mediaassetmanager-oh-mediaasset.md) instance to be requested.| 162| [MediaLibrary_RequestOptions](capi-mediaassetmanager-medialibrary-requestoptions.md) requestOptions | Options related to the media asset quality and delivery mode. The options are specified by [MediaLibrary_RequestOptions](capi-mediaassetmanager-medialibrary-requestoptions.md).| 163| [MediaLibrary_RequestId](capi-mediaassetmanager-medialibrary-requestid.md)* requestId | Pointer to the request ID, which is specified by [MediaLibrary_RequestId](capi-mediaassetmanager-medialibrary-requestid.md).| 164| [OH_MediaLibrary_OnMovingPhotoDataPrepared](capi-media-asset-base-capi-h.md#oh_medialibrary_onmovingphotodataprepared) callback | Callback to be invoked when the requested moving photo is ready. The callback is specified by [OH_MediaLibrary_OnMovingPhotoDataPrepared](capi-media-asset-base-capi-h.md#oh_medialibrary_onmovingphotodataprepared).| 165 166**Return value** 167 168| Type| Description| 169| -- | -- | 170| [MediaLibrary_ErrorCode](capi-media-asset-base-capi-h.md#medialibrary_errorcode) | **MEDIA_LIBRARY_OK**: operation success.<br>**MEDIA_LIBRARY_PARAMETER_ERROR**: incorrect parameters. Possible causes:<br> 1. A mandatory parameter is not specified.<br> 2. A parameter type is incorrect.<br> 3. Parameter verification fails.<br>**MEDIA_LIBRARY_OPERATION_NOT_SUPPORTED**: unsupported operation.<br>**MEDIA_LIBRARY_PERMISSION_DENIED**: no access permission.<br>**MEDIA_LIBRARY_INTERNAL_SYSTEM_ERROR**: internal system error.| 171 172### OH_MediaAssetManager_RequestImage() 173 174``` 175MediaLibrary_ErrorCode OH_MediaAssetManager_RequestImage(OH_MediaAssetManager* manager, OH_MediaAsset* mediaAsset,MediaLibrary_RequestOptions requestOptions, MediaLibrary_RequestId* requestId,OH_MediaLibrary_OnImageDataPrepared callback) 176``` 177 178**Description** 179 180Requests an image based on different policies. 181 182**Required permissions**: ohos.permission.READ_IMAGEVIDEO 183 184**Since**: 12 185 186 187**Parameters** 188 189| Parameter| Description| 190| -- | -- | 191| [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md)* manager | Pointer to an [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md) instance.| 192| [OH_MediaAsset](capi-mediaassetmanager-oh-mediaasset.md)* mediaAsset | Pointer to the [OH_MediaAsset](capi-mediaassetmanager-oh-mediaasset.md) instance to be requested.| 193| [MediaLibrary_RequestOptions](capi-mediaassetmanager-medialibrary-requestoptions.md) requestOptions | Options related to the media asset quality and delivery mode. The options are specified by [MediaLibrary_RequestOptions](capi-mediaassetmanager-medialibrary-requestoptions.md).| 194| [MediaLibrary_RequestId](capi-mediaassetmanager-medialibrary-requestid.md)* requestId | Pointer to the request ID, which is specified by [MediaLibrary_RequestId](capi-mediaassetmanager-medialibrary-requestid.md).| 195| [OH_MediaLibrary_OnImageDataPrepared](capi-media-asset-base-capi-h.md#oh_medialibrary_onimagedataprepared) callback | Callback to be invoked when the requested image is ready. The callback is specified by [OH_MediaLibrary_OnImageDataPrepared](capi-media-asset-base-capi-h.md#oh_medialibrary_onimagedataprepared).| 196 197**Return value** 198 199| Type| Description| 200| -- | -- | 201| [MediaLibrary_ErrorCode](capi-media-asset-base-capi-h.md#medialibrary_errorcode) | **MEDIA_LIBRARY_OK**: operation success.<br>**MEDIA_LIBRARY_PARAMETER_ERROR**: incorrect parameters. Possible causes:<br> 1. A mandatory parameter is not specified.<br> 2. A parameter type is incorrect.<br> 3. Parameter verification fails.<br>**MEDIA_LIBRARY_OPERATION_NOT_SUPPORTED**: unsupported operation.<br>**MEDIA_LIBRARY_PERMISSION_DENIED**: no access permission.<br>**MEDIA_LIBRARY_INTERNAL_SYSTEM_ERROR**: internal system error.| 202 203### OH_MediaAssetManager_Release() 204 205``` 206MediaLibrary_ErrorCode OH_MediaAssetManager_Release(OH_MediaAssetManager* manager) 207``` 208 209**Description** 210 211Releases an [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md) instance. 212 213**Since**: 13 214 215 216**Parameters** 217 218| Parameter| Description| 219| -- | -- | 220| [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md)* manager | Pointer to an [OH_MediaAssetManager](capi-mediaassetmanager-oh-mediaassetmanager.md) instance.| 221 222**Return value** 223 224| Type| Description| 225| -- | -- | 226| [MediaLibrary_ErrorCode](capi-media-asset-base-capi-h.md#medialibrary_errorcode) | **MEDIA_LIBRARY_OK**: operation success.<br>**MEDIA_LIBRARY_PARAMETER_ERROR**: incorrect parameters. Possible causes:<br> 1. A mandatory parameter is not specified.<br> 2. A parameter type is incorrect.<br> 3. Parameter verification fails.| 227