chrome.tabCapture

Description

Use the chrome.tabCapture API to interact with tab media streams.

Permissions

tabCapture

Overview

The chrome.tabCapture API allows you to access a MediaStream containing video and audio of the current tab. It can only be called after the user invokes an extension, such as by clicking the extension's action button. This is similar to the behavior of the activeTab permission.

Preserving system audio

When a MediaStream is obtained for a tab, audio in that tab will no longer be played to the user. This is similar to the behavior of the getDisplayMedia() function when the suppressLocalAudioPlayback flag is set to true.

To continue playing audio to the user, use the following:

const output = new AudioContext();
const source = output.createMediaStreamSource(stream);
source.connect(output.destination);

This creates a new AudioContext and connects the audio of the tab's MediaStream to the default destination.

Stream IDs

Calling chrome.tabCapture.getMediaStreamId will return a stream ID. To later access a MediaStream from the ID, use the following:

navigator.mediaDevices.getUserMedia({
  audio: {
    mandatory: {
      chromeMediaSource: "tab",
      chromeMediaSourceId: id,
    },
  },
  video: {
    mandatory: {
      chromeMediaSource: "tab",
      chromeMediaSourceId: id,
    },
  },
});

Usage restrictions

After calling getMediaStreamId(), there are restrictions on where the returned stream ID can be used:

  • If consumerTabId is specified, the ID can be used by a getUserMedia() call in any frame in the given tab which has the same security origin.
  • When this is not specified, begininning in Chrome 116, the ID can be used in any frame with the same security origin in the same render process as the caller. This means that a stream ID obtained in a service worker can be used in an offscreen document.

Prior to Chrome 116, when a consumerTabId was not specified, the stream ID was restricted to both the security origin, render process and render frame of the caller.

Learn more

To learn more about how to use the chrome.tabCapture API, see Audio recording and screen capture. This demonstrates how to use tabCapture and related APIs to solve a number of common use cases.

Types

CaptureInfo

Properties

  • fullscreen

    boolean

    Whether an element in the tab being captured is in fullscreen mode.

  • The new capture status of the tab.

  • tabId

    number

    The id of the tab whose status changed.

CaptureOptions

Properties

GetMediaStreamOptions

Chrome 71+

Properties

  • consumerTabId

    number optional

    Optional tab id of the tab which will later invoke getUserMedia() to consume the stream. If not specified then the resulting stream can be used only by the calling extension. The stream can only be used by frames in the given tab whose security origin matches the consumber tab's origin. The tab's origin must be a secure origin, e.g. HTTPS.

  • targetTabId

    number optional

    Optional tab id of the tab which will be captured. If not specified then the current active tab will be selected. Only tabs for which the extension has been granted the activeTab permission can be used as the target tab.

MediaStreamConstraint

Properties

  • mandatory

    object

  • optional

    object optional

TabCaptureState

Enum

"pending"

"active"

"stopped"

"error"

Methods

capture()

Foreground only 
chrome.tabCapture.capture(
  options: CaptureOptions,
  callback: function,
)

Captures the visible area of the currently active tab. Capture can only be started on the currently active tab after the extension has been invoked, similar to the way that activeTab works. Capture is maintained across page navigations within the tab, and stops when the tab is closed, or the media stream is closed by the extension.

Parameters

  • options

    CaptureOptions

    Configures the returned media stream.

  • callback

    function

    The callback parameter looks like: 

    (stream: LocalMediaStream) => void

    • stream

      LocalMediaStream

getCapturedTabs()

Promise 
chrome.tabCapture.getCapturedTabs(
  callback?: function,
)

Returns a list of tabs that have requested capture or are being captured, i.e. status != stopped and status != error. This allows extensions to inform the user that there is an existing tab capture that would prevent a new tab capture from succeeding (or to prevent redundant requests for the same tab).

Parameters

  • callback

    function optional

    The callback parameter looks like: 

    (result: CaptureInfo[]) => void

Returns

  • Promise<CaptureInfo[]>

    Chrome 116+

    Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.

getMediaStreamId()

Promise Chrome 71+ 
chrome.tabCapture.getMediaStreamId(
  options?: GetMediaStreamOptions,
  callback?: function,
)

Creates a stream ID to capture the target tab. Similar to chrome.tabCapture.capture() method, but returns a media stream ID, instead of a media stream, to the consumer tab.

Parameters

  • options

    GetMediaStreamOptions optional

  • callback

    function optional

    The callback parameter looks like: 

    (streamId: string) => void

    • streamId

      string

Returns

  • Promise<string>

    Chrome 116+

    Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.

Events

onStatusChanged

chrome.tabCapture.onStatusChanged.addListener(
  callback: function,
)

Event fired when the capture status of a tab changes. This allows extension authors to keep track of the capture status of tabs to keep UI elements like page actions in sync.

Parameters