src/cobalt/site/docs/reference/starboard/modules/drm.md

---
layout: doc
title: "Starboard Module Reference: drm.h"
---

Provides definitions that allow for DRM support, which are common between Player
and Decoder interfaces.

## Macros ##

### kSbDrmSystemInvalid ###

An invalid SbDrmSystem.

### kSbDrmTicketInvalid ###

A ticket for callback invocations initiated by the DRM system.

## Enums ##

### SbDrmEncryptionScheme ###

Encryption scheme of the input sample, as defined in ISO/IEC 23001 part 7.

#### Values ####

*   `kSbDrmEncryptionSchemeAesCtr`
*   `kSbDrmEncryptionSchemeAesCbc`

### SbDrmKeyStatus ###

Status of a particular media key. [https://w3c.github.io/encrypted-media/#idl-def-MediaKeyStatus](https://w3c.github.io/encrypted-media/#idl-def-MediaKeyStatus)

#### Values ####

*   `kSbDrmKeyStatusUsable`
*   `kSbDrmKeyStatusExpired`
*   `kSbDrmKeyStatusReleased`
*   `kSbDrmKeyStatusRestricted`
*   `kSbDrmKeyStatusDownscaled`
*   `kSbDrmKeyStatusPending`
*   `kSbDrmKeyStatusError`

### SbDrmSessionRequestType ###

The type of the session request. [https://www.w3.org/TR/encrypted-media/#idl-def-mediakeymessagetype](https://www.w3.org/TR/encrypted-media/#idl-def-mediakeymessagetype)

#### Values ####

*   `kSbDrmSessionRequestTypeLicenseRequest`
*   `kSbDrmSessionRequestTypeLicenseRenewal`
*   `kSbDrmSessionRequestTypeLicenseRelease`
*   `kSbDrmSessionRequestTypeIndividualizationRequest`

### SbDrmStatus ###

The status of session related operations. Used by
`SbDrmSessionUpdateRequestFunc`, `SbDrmSessionUpdatedFunc`, and
`SbDrmServerCertificateUpdatedFunc` to indicate the status of the operation. [https://w3c.github.io/encrypted-media/#error-names](https://w3c.github.io/encrypted-media/#error-names)

#### Values ####

*   `kSbDrmStatusSuccess`
*   `kSbDrmStatusTypeError`
*   `kSbDrmStatusNotSupportedError`
*   `kSbDrmStatusInvalidStateError`
*   `kSbDrmStatusQuotaExceededError`
*   `kSbDrmStatusUnknownError`

    The following error can be used when the error status cannot be mapped to
    one of the above errors.

## Typedefs ##

### SbDrmServerCertificateUpdatedFunc ###

A callback to notify the caller of SbDrmUpdateServerCertificate() whether the
update has been successfully updated or not.

#### Definition ####

```
typedef void(* SbDrmServerCertificateUpdatedFunc) (SbDrmSystem drm_system, void *context, int ticket, SbDrmStatus status, const char *error_message)
```

### SbDrmSessionClosedFunc ###

A callback for signalling that a session has been closed by the SbDrmSystem

#### Definition ####

```
typedef void(* SbDrmSessionClosedFunc) (SbDrmSystem drm_system, void *context, const void *session_id, int session_id_size)
```

### SbDrmSessionKeyStatusesChangedFunc ###

A callback for notifications that the status of one or more keys in a session
has been changed. All keys of the session and their new status will be passed
along. Any keys not in the list is considered as deleted.

#### Definition ####

```
typedef void(* SbDrmSessionKeyStatusesChangedFunc) (SbDrmSystem drm_system, void *context, const void *session_id, int session_id_size, int number_of_keys, const SbDrmKeyId *key_ids, const SbDrmKeyStatus *key_statuses)
```

### SbDrmSessionUpdateRequestFunc ###

A callback that will receive generated session update request when requested
from a SbDrmSystem. `drm_system` will be the DRM system that
SbDrmGenerateSessionUpdateRequest() was called on. `context` will be the same
context that was passed into the call to SbDrmCreateSystem().

`status` is the status of the session request.

`type` is the status of the session request.

`error_message` may contain an optional error message when `status` isn't
`kSbDrmStatusSuccess` to provide more details about the error. It may be NULL if
`status` is `kSbDrmStatusSuccess` or if no error message can be provided.
`ticket` will be the same ticket that was passed to
SbDrmGenerateSessionUpdateRequest() or `kSbDrmTicketInvalid` if the update
request was generated by the DRM system.

`session_id` cannot be NULL when `ticket` is `kSbDrmTicketInvalid`, even when
there was an error generating the request. This allows Cobalt to find and reject
the correct Promise corresponding to the associated
SbDrmGenerateSessionUpdateRequest().

#### Definition ####

```
typedef void(* SbDrmSessionUpdateRequestFunc) (SbDrmSystem drm_system, void *context, int ticket, SbDrmStatus status, SbDrmSessionRequestType type, const char *error_message, const void *session_id, int session_id_size, const void *content, int content_size, const char *url)
```

### SbDrmSessionUpdatedFunc ###

A callback for notifications that a session has been added, and subsequent
encrypted samples are actively ready to be decoded. `drm_system` will be the DRM
system that SbDrmUpdateSession() was called on. `context` will be the same
context passed into that call to SbDrmCreateSystem().

`ticket` will be the same ticket that was passed to SbDrmUpdateSession().

`status` is the status of the session request.

`error_message` may contain an optional error message when `status` isn't
`kSbDrmStatusSuccess` to provide more details about the error. It may be NULL if
`status` is `kSbDrmStatusSuccess` or if no error message can be provided.
`succeeded` is whether the session was successfully updated or not.

#### Definition ####

```
typedef void(* SbDrmSessionUpdatedFunc) (SbDrmSystem drm_system, void *context, int ticket, SbDrmStatus status, const char *error_message, const void *session_id, int session_id_size)
```

### SbDrmSystem ###

A handle to a DRM system which can be used with either an SbDecoder or a
SbPlayer.

#### Definition ####

```
typedef struct SbDrmSystemPrivate* SbDrmSystem
```

## Structs ##

### SbDrmEncryptionPattern ###

Encryption pattern of the input sample, as defined in ISO/IEC 23001 part 7.

#### Members ####

*   `uint32_t crypt_byte_block`
*   `uint32_t skip_byte_block`

### SbDrmKeyId ###

#### Members ####

*   `uint8_t identifier`

    The ID of the license (or key) required to decrypt this sample. For
    PlayReady, this is the license GUID in packed little-endian binary form.
*   `int identifier_size`

### SbDrmSampleInfo ###

All the optional information needed per sample for encrypted samples.

#### Members ####

*   `SbDrmEncryptionScheme encryption_scheme`

    The encryption scheme of this sample.
*   `SbDrmEncryptionPattern encryption_pattern`

    The encryption pattern of this sample.
*   `uint8_t initialization_vector`

    The Initialization Vector needed to decrypt this sample.
*   `int initialization_vector_size`
*   `uint8_t identifier`

    The ID of the license (or key) required to decrypt this sample. For
    PlayReady, this is the license GUID in packed little-endian binary form.
*   `int identifier_size`
*   `int32_t subsample_count`

    The number of subsamples in this sample, must be at least 1.
*   `constSbDrmSubSampleMapping* subsample_mapping`

    The clear/encrypted mapping of each subsample in this sample. This must be
    an array of `subsample_count` mappings.

### SbDrmSubSampleMapping ###

A mapping of clear and encrypted bytes for a single subsample. All subsamples
within a sample must be encrypted with the same encryption parameters. The clear
bytes always appear first in the sample.

#### Members ####

*   `int32_t clear_byte_count`

    How many bytes of the corresponding subsample are not encrypted
*   `int32_t encrypted_byte_count`

    How many bytes of the corresponding subsample are encrypted.

## Functions ##

### SbDrmCloseSession ###

Clear any internal states/resources related to the specified `session_id`.

#### Declaration ####

```
void SbDrmCloseSession(SbDrmSystem drm_system, const void *session_id, int session_id_size)
```

### SbDrmDestroySystem ###

Destroys `drm_system`, which implicitly removes all keys installed in it and
invalidates all outstanding session update requests. A DRM system cannot be
destroyed unless any associated SbPlayer or SbDecoder has first been destroyed.

All callbacks are guaranteed to be finished when this function returns. As a
result, if this function is called from a callback that is passed to
SbDrmCreateSystem(), a deadlock will occur.

`drm_system`: The DRM system to be destroyed.

#### Declaration ####

```
void SbDrmDestroySystem(SbDrmSystem drm_system)
```

### SbDrmGenerateSessionUpdateRequest ###

Asynchronously generates a session update request payload for
`initialization_data`, of `initialization_data_size`, in case sensitive `type`,
extracted from the media stream, in `drm_system`'s key system.

This function calls `drm_system`'s `update_request_callback` function, which is
defined when the DRM system is created by SbDrmCreateSystem. When calling that
function, this function either sends `context` (also from `SbDrmCreateSystem`)
and a populated request, or it sends NULL `session_id` if an error occurred.

`drm_system`'s `context` may be used to route callbacks back to an object
instance.

Callbacks may be called either from the current thread before this function
returns or from another thread.

`drm_system`: The DRM system that defines the key system used for the session
update request payload as well as the callback function that is called as a
result of the function being called.

`ticket`: The opaque ID that allows to distinguish callbacks from multiple
concurrent calls to SbDrmGenerateSessionUpdateRequest(), which will be passed to
`update_request_callback` as-is. It is the responsibility of the caller to
establish ticket uniqueness, issuing multiple requests with the same ticket may
result in undefined behavior. The value `kSbDrmTicketInvalid` must not be used.

`type`: The case-sensitive type of the session update request payload.
`initialization_data`: The data for which the session update request payload is
created. `initialization_data_size`: The size of the session update request
payload.

#### Declaration ####

```
void SbDrmGenerateSessionUpdateRequest(SbDrmSystem drm_system, int ticket, const char *type, const void *initialization_data, int initialization_data_size)
```

### SbDrmGetMetrics ###

Get the metrics of the underlying drm system.

When it is called on an implementation that supports drm system metrics, it
should return a pointer containing the metrics as a blob, encoded using url safe
base64 without padding and line wrapping, with the size of the encoded result in
`size` on return. For example, on Android API level 28 or later, it should
return the result of MediaDrm.getPropertyByteArray("metrics"), encoded using url
safe base64 without padding and line wrapping. On systems using Widevine CE CDM
with oemcrypto 16 or later, it should return the metrics retrieved via
Cdm::getMetrics(), encoded using url safe base64 without padding and line
wrapping. The returned pointer should remain valid and its content should remain
unmodified until the next time this function is called on the associated
`drm_system` or the `drm_system` is destroyed.

When the metrics is empty on supported system, it should return a non-null
pointer with `size` set to 0.

It should return NULL when there is no metrics support in the underlying drm
system, or when the drm system implementation fails to retrieve the metrics.

The caller will never set `size` to NULL.

#### Declaration ####

```
const void* SbDrmGetMetrics(SbDrmSystem drm_system, int *size)
```

### SbDrmIsServerCertificateUpdatable ###

Returns true if server certificate of `drm_system` can be updated via
SbDrmUpdateServerCertificate(). The return value should remain the same during
the life time of `drm_system`.

`drm_system`: The DRM system to check if its server certificate is updatable.

#### Declaration ####

```
bool SbDrmIsServerCertificateUpdatable(SbDrmSystem drm_system)
```

### SbDrmSystemIsValid ###

Indicates whether `drm_system` is a valid SbDrmSystem.

#### Declaration ####

```
static bool SbDrmSystemIsValid(SbDrmSystem drm)
```

### SbDrmTicketIsValid ###

Indicates whether `ticket` is a valid ticket.

#### Declaration ####

```
static bool SbDrmTicketIsValid(int ticket)
```

### SbDrmUpdateServerCertificate ###

Update the server certificate of `drm_system`. The function can be called
multiple times. It is possible that a call to it happens before the callback of
a previous call is called. Note that this function should only be called after
`SbDrmIsServerCertificateUpdatable` is called first and returned true.

`drm_system`: The DRM system whose server certificate is being updated.
`ticket`: The opaque ID that allows to distinguish callbacks from multiple
concurrent calls to SbDrmUpdateServerCertificate(), which will be passed to
`server_certificate_updated_callback` as-is. It is the responsibility of the
caller to establish ticket uniqueness, issuing multiple requests with the same
ticket may result in undefined behavior. The value `kSbDrmTicketInvalid` must
not be used. `certificate`: Pointer to the server certificate data.
`certificate_size`: Size of the server certificate data.

#### Declaration ####

```
void SbDrmUpdateServerCertificate(SbDrmSystem drm_system, int ticket, const void *certificate, int certificate_size)
```

### SbDrmUpdateSession ###

Update session with `key`, in `drm_system`'s key system, from the license server
response. Calls `session_updated_callback` with `context` and whether the update
succeeded. `context` may be used to route callbacks back to an object instance.

`ticket` is the opaque ID that allows to distinguish callbacks from multiple
concurrent calls to SbDrmUpdateSession(), which will be passed to
`session_updated_callback` as-is. It is the responsibility of the caller to
establish ticket uniqueness, issuing multiple calls with the same ticket may
result in undefined behavior.

Once the session is successfully updated, an SbPlayer or SbDecoder associated
with that DRM key system will be able to decrypt encrypted samples.

`drm_system`'s `session_updated_callback` may called either from the current
thread before this function returns or from another thread.

#### Declaration ####

```
void SbDrmUpdateSession(SbDrmSystem drm_system, int ticket, const void *key, int key_size, const void *session_id, int session_id_size)
```