An app can record the video or audio that is being played from another app. Such
apps must handle the
correctly. This page explains how. It also shows how a device admin can disable
the ability to record any screen snapshots, and how an audio app can prevent
other apps from recording the content it plays.
How to handle a
allows apps to acquire a
MediaProjection token that gives them one time access
to capture screen contents or audio. The Android OS asks the user for their
permission before granting the token to your app.
The OS displays the active
MediaProjection tokens in the Quick Settings UI and
allows users to withdraw access to a token at any time. When this happens the
virtual displays or audio streams associated with the session stop receiving
media streams. Your app must respond appropriately, otherwise it will continue
to record audio silence or a black video stream.
To handle the loss of a token, register a callback on the
instance using the
method, and stop recording when the
method is called.
See the ScreenCapture sample app to learn how to learn how to use Media Projection API to capture a device's screen in real time and show it on a SurfaceView.
You can use the
to prevent screen recording. For enterprise accounts (Android for Work), the
administrator can disable the collection of assistant data for the work profile
by using the
The codelab Managing Android Devices Without an App shows how to forbid screenshots.
Capture audio playback
The AudioPlaybackCapture API was introduced in Android 10. This API gives apps the ability to copy the audio being played by other apps. This feature is the analog of screen capture, but for audio. The primary use case is for streaming apps that want to capture the audio being played by games.
Note that the AudioPlaybackCapture API does not affect the latency of the app whose audio is being captured.
Building a capture app
For security and privacy, playback capture imposes some limitations. To be able to capture audio, an app must meet these requirements:
- The app must have the
- The app must bring up the prompt displayed by
MediaProjectionManager.createScreenCaptureIntent(), and the user must approve it.
- The capturing and playing apps must be in the same user profile.
To capture audio from another app, your app must build an
and add an
to it. Follow these steps:
AudioPlaybackCaptureConfiguration.Builder.build()to build an
- Pass the configuration to the
Controlling audio capture
Your app can control what types of content it can record, and what other kinds of app can record its own playback.
Constraining capture by audio content
An app can limit which audio it can capture by using these methods:
- Pass an
AUDIO_USAGEto AudioPlaybackCaptureConfiguration.addMatchingUsage() to permit capturing a specific usage. Call the method multiple times to specify more than one usage.
- Pass an
AUDIO_USAGEto AudioPlaybackCaptureConfiguration.excludeUsage() to forbid capturing that usage. Call the method multiple times to specify more than one usage.
- Pass a UID to AudioPlaybackCaptureConfiguration.addMatchingUid() to only capture apps with a specific UID. Call the method multiple times to specify more than one UID.
- Pass a UID to AudioPlaybackCaptureConfiguration.excludeUid() to forbid capturing that UID. Call the method multiple times to specify more than one UID.
Note that you cannot use the
together. You must choose one or the other. Likewise, you cannot use
at the same time.
Constraining capture by other apps
You can configure an app to prevent other apps from capturing its audio. The audio coming from an app can be captured only if the app meets these requirements:
The player producing the audio must set its usage
The player's capture policy must be
which allows other apps to capture playback. This can be done in a number of ways:
- To enable capture on all players, include
android:allowAudioPlaybackCapture="true"in the app's
- You can also enable capture on all players by calling
- You can set the policy on an individual player when you build it using
AudioAttributes.Builder.setAllowedCapturePolicy(AudioAttributes.ALLOW_CAPTURE_BY_ALL). (If you are using
If these prerequisites are met, any audio produced by the player can be captured.
Disabling system capture
The protections permitting capture described above apply only to apps. Android
system components can capture playback by default.
Many of these components are customized by Android vendors and support features
like accessibility and captioning. For this reason it is recommended that apps
allow the system to capture their playback. In the rare case when you do not
want the system to capture your app's playback, set the capture policy to
Setting policy at runtime
You can call
AudioManager.setAllowedCapturePolicy() to change the capture
policy while an app is running. If a MediaPlayer or AudioTrack is playing
when you call the method, the audio is not affected. You must close and reopen
the player or track for the policy change to take effect.
Policy = manifest + AudioManager + AudioAttributes
Since the capture policy can be specified in several places, it's important
to understand how the effective policy is determined.
The most restrictive capture policy is always applied. For example, an app whose
setAllowedCapturePolicy="false" will never permit non-system
apps to capture its audio, even if
AudioManager#setAllowedCapturePolicy is set
ALLOW_CAPTURE_BY_ALL. Similarly, if the
AudioManager#setAllowedCapturePolicy is set to
ALLOW_CAPTURE_BY_ALL and the
setAllowedCapturePolicy="true", but the media player's
AudioAttributes were built with
this media player will not be capturable by non-system apps.
The table below summarizes the effect of the manifest attribute and the effective policy:
|true||any app||system only||no capture|
|false||system only||system only||no capture|