# Interface (MediaKeySession)

> **NOTE**
>
> The initial APIs of this module are supported since API version 11. Newly added APIs will be marked with a superscript to indicate their earliest API version.

MediaKeySession implements media key management. Before calling any API in MediaKeySession, you must use [createMediaKeySession](arkts-apis-drm-MediaKeySystem.md#createmediakeysession) to create a MediaKeySession instance.

## Modules to Import

```ts
import { drm } from '@kit.DrmKit';
```

## generateMediaKeyRequest

generateMediaKeyRequest(mimeType: string, initData: Uint8Array, mediaKeyType: number, options?: OptionsData[]): Promise<MediaKeyRequest\>

Generates a media key request.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name    | Type                                            | Mandatory| Description                          |
| -------- | ----------------------------------------------- | ---- | ---------------------------- |
| mimeType  | string     | Yes  | MIME type, which is determined by the DRM solution.                  |
| initData  | Uint8Array     | Yes  | Initial data.                  |
| mediaKeyType| number     | Yes  | Type of the media key. The value **0** means an online media key, and **1** means an offline media key.|
| options  | [OptionsData[]](arkts-apis-drm-i.md#optionsdata)     | No  | Optional data.                  |

**Return value**

| Type                                            | Description                          |
| ----------------------------------------------- | ---------------------------- |
| Promise<[MediaKeyRequest](arkts-apis-drm-i.md#mediakeyrequest)\>          | Promise used to return the media key request generated.                  |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                | The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.              |
| 24700101                |  All unknown errors                  |
| 24700201                |  Fatal service error, for example, service died                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';
import { BusinessError } from '@kit.BasicServicesKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
// PSSH data is the descriptive header of the copyright protection system and is encapsulated in encrypted streams. Specifically, in MP4 file, the PSSH data is found within the PSSH box; for DASH streams, the PSSH data is located in the MPD and MP4 PSSH box; for HLS+TS streams, the PSSH data is located in the M3U8 file and each TS segment. Pass in the actual value.
let uint8pssh = new Uint8Array([0x00, 0x00, 0x00, 0x00]);
mediaKeySession.generateMediaKeyRequest("video/avc", uint8pssh, drm.MediaKeyType.MEDIA_KEY_TYPE_ONLINE).then((mediaKeyRequest: drm.MediaKeyRequest) =>{
  console.log('generateMediaKeyRequest' + mediaKeyRequest);
}).catch((err: BusinessError) => {
  console.error(`generateMediaKeyRequest: ERROR: ${err}`);
});
```

## processMediaKeyResponse

processMediaKeyResponse(response: Uint8Array): Promise<Uint8Array\>

Processes a media key response.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name    | Type                                            | Mandatory| Description                          |
| -------- | ----------------------------------------------- | ---- | ---------------------------- |
| response  | Uint8Array     | Yes  | Media key response.                  |

**Return value**

| Type                                            | Description                          |
| ----------------------------------------------- | ---------------------------- |
| Promise<Uint8Array\>          | Promise used to return the media key IDs.                  |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types. 3.Parameter verification failed.            |
| 24700101                |  All unknown errors                  |
| 24700201                |  Fatal service error, for example, service died                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';
import { BusinessError } from '@kit.BasicServicesKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
// mediaKeyResponse is obtained from the DRM service. Pass in the actual value obtained.
let mediaKeyResponse = new Uint8Array([0x00, 0x00, 0x00, 0x00]);
mediaKeySession.processMediaKeyResponse(mediaKeyResponse).then((mediaKeyId: Uint8Array) => {
  console.log('processMediaKeyResponse:' + mediaKeyId);
}).catch((err: BusinessError) => {
  console.error(`processMediaKeyResponse: ERROR: ${err}`);
});
```

## checkMediaKeyStatus

 checkMediaKeyStatus(): MediaKeyStatus[]

Checks the status of the media keys in use.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Return value**

| Type                                            | Description                          |
| ----------------------------------------------- | ---------------------------- |
| [MediaKeyStatus[]](arkts-apis-drm-i.md#mediakeystatus)          | Media key status.                  |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 24700101                |  All unknown errors                  |
| 24700201                |  Fatal service error, for example, service died                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';
import { BusinessError } from '@kit.BasicServicesKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
try {
  let keyStatus: drm.MediaKeyStatus[] =  mediaKeySession.checkMediaKeyStatus();
} catch (err) {
  let error = err as BusinessError;
  console.error(`checkMediaKeyStatus ERROR: ${error}`);
}
```

## clearMediaKeys

clearMediaKeys(): void

Clears the media keys in use.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 24700101                |  All unknown errors                  |
| 24700201                |  Fatal service error, for example, service died                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';
import { BusinessError } from '@kit.BasicServicesKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
// mediaKeyResponse is obtained from the DRM service. Pass in the actual value obtained.
let mediaKeyResponse = new Uint8Array([0x00, 0x00, 0x00, 0x00]);
mediaKeySession.processMediaKeyResponse(mediaKeyResponse).then((mediaKeyId: Uint8Array) => {
  console.log('processMediaKeyResponse:' + mediaKeyId);
}).catch((err: BusinessError) => {
  console.error(`processMediaKeyResponse: ERROR: ${err}`);
});
try {
  mediaKeySession.clearMediaKeys();
} catch (err) {
  let error = err as BusinessError;
  console.error(`clearMediaKeys ERROR: ${error}`);
}
```

## generateOfflineReleaseRequest

generateOfflineReleaseRequest(mediaKeyId: Uint8Array): Promise<Uint8Array\>

Generates a request to release offline media keys.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name    | Type                                            | Mandatory| Description                          |
| -------- | ----------------------------------------------- | ---- | ---------------------------- |
| mediaKeyId  | Uint8Array    | Yes  | Array holding the IDs of offline media keys.                  |

**Return value**

| Type                                            | Description                          |
| ----------------------------------------------- | ---------------------------- |
| Promise<Uint8Array\>          | Promise used to return the request generated if the DRM solution on the device supports offline media key release.                  |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.         |
| 24700101                |  All unknown errors                  |
| 24700201                |  Fatal service error, for example, service died                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';
import { BusinessError } from '@kit.BasicServicesKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
// mediaKeyId is the return value of processMediaKeyResponse or getOfflineMediaKeyIds. Pass in the actual data returned.
let mediaKeyId = new Uint8Array([0x00, 0x00, 0x00, 0x00]);
mediaKeySession.generateOfflineReleaseRequest(mediaKeyId).then((offlineReleaseRequest: Uint8Array) => {
  console.log('generateOfflineReleaseRequest:' + offlineReleaseRequest);
}).catch((err: BusinessError) => {
  console.error(`generateOfflineReleaseRequest: ERROR: ${err}`);
});
```

## processOfflineReleaseResponse

processOfflineReleaseResponse(mediaKeyId: Uint8Array, response: Uint8Array): Promise<void\>

Processes a response to a request for releasing offline media keys.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name    | Type                                            | Mandatory| Description                          |
| -------- | ----------------------------------------------- | ---- | ---------------------------- |
| mediaKeyId  | Uint8Array     | Yes  | Array holding the IDs of offline media keys.                  |
| response  | Uint8Array     | Yes  | Response to the request for releasing offline media keys.                  |

**Return value**

| Type                                            | Description                          |
| ----------------------------------------------- | ---------------------------- |
| Promise<void\>          | Promise used to return the result if the DRM solution on the device supports offline media key release.                  |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.            |
| 24700101                |  All unknown errors                  |
| 24700201                |  Fatal service error, for example, service died                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';
import { BusinessError } from '@kit.BasicServicesKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
// mediaKeyId is the return value of processMediaKeyResponse or getOfflineMediaKeyIds. Apply for memory based on the actual length.
let mediaKeyId = new Uint8Array([0x00, 0x00, 0x00, 0x00]);
mediaKeySession.generateOfflineReleaseRequest(mediaKeyId).then((offlineReleaseRequest: Uint8Array) => {
  console.log('generateOfflineReleaseRequest:' + offlineReleaseRequest);
}).catch((err: BusinessError) => {
  console.error(`generateOfflineReleaseRequest: ERROR: ${err}`);
});
// offlineReleaseResponse is obtained from the DRM service. Apply for memory based on the actual length.
let offlineReleaseResponse = new Uint8Array([0x00, 0x00, 0x00, 0x00]);
mediaKeySession.processOfflineReleaseResponse(mediaKeyId, offlineReleaseResponse).then(() => {
  console.log('processOfflineReleaseResponse');
}).catch((err: BusinessError) => {
  console.error(`processOfflineReleaseResponse: ERROR: ${err}`);
});
```

## restoreOfflineMediaKeys

restoreOfflineMediaKeys(mediaKeyId: Uint8Array): Promise<void\>

Restores offline media keys.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name    | Type                                            | Mandatory| Description                          |
| -------- | ----------------------------------------------- | ---- | ---------------------------- |
| mediaKeyId  | Uint8Array     | Yes  | Array holding the IDs of offline media keys.                  |

**Return value**

| Type                                            | Description                          |
| ----------------------------------------------- | ---------------------------- |
| Promise<void\>          | Promise                  |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.              |
| 24700101                |  All unknown errors                  |
| 24700201                |  Fatal service error, for example, service died                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';
import { BusinessError } from '@kit.BasicServicesKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
// mediaKeyId is the return value of processMediaKeyResponse or getOfflineMediaKeyIds. Pass in the actual data returned.
let mediaKeyId = new Uint8Array([0x00, 0x00, 0x00, 0x00]);
mediaKeySession.restoreOfflineMediaKeys(mediaKeyId).then(() => {
  console.log("restoreOfflineMediaKeys");
}).catch((err: BusinessError) => {
  console.error(`restoreOfflineMediaKeys: ERROR: ${err}`);
});
```

## getContentProtectionLevel

getContentProtectionLevel(): ContentProtectionLevel

Obtains the content protection level of this media key session.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Return value**

| Type                                            | Description                          |
| ----------------------------------------------- | ---------------------------- |
| [ContentProtectionLevel](arkts-apis-drm-e.md#contentprotectionlevel)          | Content protection level.                  |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 24700101                |  All unknown errors                  |
| 24700201                |  Fatal service error, for example, service died                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';
import { BusinessError } from '@kit.BasicServicesKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
try {
  let contentProtectionLevel: drm.ContentProtectionLevel = mediaKeySession.getContentProtectionLevel();
} catch (err) {
  let error = err as BusinessError;
  console.error(`getContentProtectionLevel ERROR: ${error}`);
}
```

## requireSecureDecoderModule

requireSecureDecoderModule(mimeType: string): boolean

Checks whether secure decoding is required.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name    | Type                                            | Mandatory| Description                          |
| -------- | ----------------------------------------------- | ---- | ---------------------------- |
| mimeType  | string     | Yes  | MIME type, which is determined by the DRM solution.                  |

**Return value**

| Type                                            | Description                          |
| ----------------------------------------------- | ---------------------------- |
| boolean          | Whether secure decoding is required. **true** if required, **false** otherwise.                  |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.      |
| 24700101                |  All unknown errors                  |
| 24700201                |  Fatal service error, for example, service died                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';
import { BusinessError } from '@kit.BasicServicesKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
try {
  let status: boolean = mediaKeySession.requireSecureDecoderModule("video/avc");
} catch (err) {
  let error = err as BusinessError;
  console.error(`requireSecureDecoderModule ERROR: ${error}`);
} 
```

## on('keyRequired')

on(type: 'keyRequired', callback: (eventInfo: EventInfo) => void): void

Subscribes to events indicating that the application requests a media key.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                                 |
| -------- | -------------------- | ---- | ------------------------------------- |
| type     | string               | Yes  | Event type. The value is fixed at **'keyRequired'**. This event is triggered when the application requires a media key.|
| callback | (eventInfo: \<[EventInfo](arkts-apis-drm-i.md#eventinfo)\>) => void  | Yes  | Callback used to return the event information.                |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.         |
| 24700101                |  All unknown errors                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
mediaKeySession.on('keyRequired', (eventInfo: drm.EventInfo) => {
  console.log('keyRequired ' + 'extra: ' + eventInfo.extraInfo + 'data: ' + eventInfo.info);
});
```

## off('keyRequired')

off(type: 'keyRequired', callback?: (eventInfo: EventInfo) => void): void

Unsubscribes from events indicating that the application requests a media key.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                                 |
| -------- | -------------------- | ---- | ------------------------------------- |
| type     | string               | Yes  | Event type. The value is fixed at **'keyRequired'**.|
| callback | (eventInfo: \<[EventInfo](arkts-apis-drm-i.md#eventinfo)\>) => void  | No  | Callback used to return the event information.                 |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.             |
| 24700101                |  All unknown errors                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
mediaKeySession.off('keyRequired');
```

## on('keyExpired')

on(type: 'keyExpired', callback: (eventInfo: EventInfo) => void): void

Subscribes to events indicating that a media key expires.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                                 |
| -------- | -------------------- | ---- | ------------------------------------- |
| type     | string               | Yes  | Event type. The value is fixed at **'keyExpired'**. This event is triggered when a media key expires.|
| callback | (eventInfo: \<[EventInfo](arkts-apis-drm-i.md#eventinfo)\>) => void  | Yes  | Callback used to return the event information.                |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.          |
| 24700101                |  All unknown errors                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
mediaKeySession.on('keyExpired', (eventInfo: drm.EventInfo) => {
  console.log('keyExpired ' + 'extra: ' + eventInfo.extraInfo + 'data: ' + eventInfo.info);
});
```

## off('keyExpired')

off(type: 'keyExpired', callback?: (eventInfo: EventInfo) => void): void

Unsubscribes from events indicating that a media key expires.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                                 |
| -------- | -------------------- | ---- | ------------------------------------- |
| type     | string               | Yes  | Event type. The value is fixed at **'keyExpired'**.|
| callback | (eventInfo: \<[EventInfo](arkts-apis-drm-i.md#eventinfo)\>) => void  | No  | Callback used to return the event information.                 |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.            |
| 24700101                |  All unknown errors                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
mediaKeySession.off('keyExpired');
```

## on('vendorDefined')

on(type: 'vendorDefined', callback: (eventInfo: EventInfo) => void): void

Subscribes to vendor-defined events.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                                 |
| -------- | -------------------- | ---- | ------------------------------------- |
| type     | string               | Yes  | Event type. The value is fixed at **'vendorDefined'**. This event is triggered when a vendor-defined event occurs.|
| callback | (eventInfo: \<[EventInfo](arkts-apis-drm-i.md#eventinfo)\>) => void  | Yes  | Callback used to return the event information.                |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.              |
| 24700101                |  All unknown errors                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
mediaKeySession.on('vendorDefined', (eventInfo: drm.EventInfo) => {
  console.log('vendorDefined ' + 'extra: ' + eventInfo.extraInfo + 'data: ' + eventInfo.info);
});
```

## off('vendorDefined')

off(type: 'vendorDefined', callback?: (eventInfo: EventInfo) => void): void

Unsubscribes from vendor-defined events.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                                 |
| -------- | -------------------- | ---- | ------------------------------------- |
| type     | string               | Yes  | Event type. The value is fixed at **'vendorDefined'**.|
| callback | (eventInfo: \<[EventInfo](arkts-apis-drm-i.md#eventinfo)\>) => void  | No  | Callback used to return the event information.                 |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.      |
| 24700101                |  All unknown errors                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
mediaKeySession.off('vendorDefined');
```

## on('expirationUpdate')

on(type: 'expirationUpdate', callback: (eventInfo: EventInfo) => void): void

Subscribes to events indicating that a media key updates on expiry.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                                 |
| -------- | -------------------- | ---- | ------------------------------------- |
| type     | string               | Yes  | Event type. The value is fixed at **'expirationUpdate'**. This event is triggered when a media key updates on expiry.|
| callback | (eventInfo: \<[EventInfo](arkts-apis-drm-i.md#eventinfo)\>) => void  | Yes  | Callback used to return the event information.                |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.        |
| 24700101                |  All unknown errors                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
mediaKeySession.on('expirationUpdate', (eventInfo: drm.EventInfo) => {
  console.log('expirationUpdate ' + 'extra: ' + eventInfo.extraInfo + 'data: ' + eventInfo.info);
});
```

## off('expirationUpdate')

off(type: 'expirationUpdate', callback?: (eventInfo: EventInfo) => void): void

Unsubscribes from events indicating that a media key updates on expiry. 

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                                 |
| -------- | -------------------- | ---- | ------------------------------------- |
| type     | string               | Yes  | Event type. The value is fixed at **'expirationUpdate'**.|
| callback | (eventInfo: \<[EventInfo](arkts-apis-drm-i.md#eventinfo)\>) => void  | No  | Callback used to return the event information.                 |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.       |
| 24700101                |  All unknown errors                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
mediaKeySession.off('expirationUpdate');
```

## on('keysChange')

on(type: 'keysChange', callback: (keyInfo: KeysInfo[], newKeyAvailable: boolean) => void): void

Subscribes to events indicating that a media key changes.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                                 |
| -------- | -------------------- | ---- | ------------------------------------- |
| type     | string               | Yes  | Event type. The value is fixed at **'keysChange'**. This event is triggered when a media key changes.|
| callback | (keyInfo: [KeysInfo[]](arkts-apis-drm-i.md#keysinfo), newKeyAvailable: boolean) | Yes  | Callback used to return the event information, including the lists of key IDs, statuses, and availability.                |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.             |
| 24700101                |  All unknown errors                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
mediaKeySession.on('keysChange', (keyInfo: drm.KeysInfo[], newKeyAvailable: boolean) => {
  for (let i = 0; i < keyInfo.length; i++) {
    console.log('keysChange' + 'keyId:' + keyInfo[i].keyId + ' data:' + keyInfo[i].value);
  }
});
```

## off('keysChange')

off(type: 'keysChange', callback?: (keyInfo: KeysInfo[], newKeyAvailable: boolean) => void): void

Unsubscribes from events indicating that a media key changes.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                                 |
| -------- | -------------------- | ---- | ------------------------------------- |
| type     | string               | Yes  | Event type. The value is fixed at **'keysChange'**.|
| callback | (keyInfo: [KeysInfo[]](arkts-apis-drm-i.md#keysinfo), newKeyAvailable: boolean) | No  | Callback used to return the event information, including the lists of key IDs, statuses, and availability.               |

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 401                |  The parameter check failed. Possibly because: 1.Mandatory parameters are left unspecified or too many parameters. 2.Incorrect parameter types. 3.Parameter verification failed.            |
| 24700101                |  All unknown errors                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
mediaKeySession.off('keysChange');
```

## destroy

destroy(): void

Destroys this MediaKeySession instance.

**Atomic service API**: This API can be used in atomic services since API version 12.

**System capability**: SystemCapability.Multimedia.Drm.Core

**Error codes**

For details about the error codes, see [DRM Error Codes](errorcode-drm.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 24700101                |  All unknown errors                  |
| 24700201                |  Fatal service error, for example, service died                  |

**Example**

```ts
import { drm } from '@kit.DrmKit';
import { BusinessError } from '@kit.BasicServicesKit';

let mediaKeySystem: drm.MediaKeySystem = drm.createMediaKeySystem("com.clearplay.drm");
let mediaKeySession: drm.MediaKeySession = mediaKeySystem.createMediaKeySession();
try {
  mediaKeySession.destroy();
} catch (err) {
  let error = err as BusinessError;
  console.error(`mediaKeySession destroy ERROR: ${error}`);
}

```