What to do when your web browser triggers the video content protection mechanism

This article explains how video content protection is performed by your web browser, what can trigger it and potential options to avoid having your playback interrupted by it


  • Digital Theatre+ videos are protected using encryption in order to prevent content theft
  • The decryption of videos is controlled by your web browser, not Digital Theatre+
  • If your web browser thinks that content theft may be taking place, due to the display not being trusted, it will not display the video and may only play audio
  • To avoid this content protection preventing video playback, you must use a display that does not trigger the web browser's content protection mechanism
  • When using external display devices, an additional technology is involved to ensure the encryption of content is maintained between the output device and display

Digital Theatre+ does not control the content protection mechanism, it is controlled by your web browser and the equipment you use.

What triggers the content protection mechanism?

When you play protected content, if you use a display that the CDM does not trust, it will not allow your browser to display video.

Connections to external displays must support High Definition Content Protection (HDCP).  HDCP is additional encryption that protects digital audio and video from being copied through physical connections between devices. 

If your display does not support HDCP, the CDM will not send video to it.

Browser manufactures do not provide information on how their CDMs work, or what causes the content protection mechanism to trigger, however from our experience:

  • Integrated displays, such as screens on laptops, do not experience issues
  • HDCP compliant displays connected with cables that use digital signals (such as HDMI, DisplayPort and DVI) rarely experience issues.  
  • Displays connected wirelessly are most likely to encounter issues
  • Displays connected with cables that use analog signals (such as VGA) are not expected to work

How do I know if my display supports HDCP?

  1. Check the device itself. It may have a label on it stating that it supports HDCP
  2. If there is no label on the display, check the manual that it came with; the display’s specifications may include this information
  3. If you can’t find the box or the manual, try searching the manufacturer website specifications

What to do if your display does support HDCP and content protection is preventing the video signal being sent

One of the following may resolve the issue:

  1. Restart the display device and computer
  2. Disable screen sharing - screen sharing may trigger content protection if the software you're using causes either HDCP or the CDM to believe the connection to the display is no longer secure
  3. Disable screen capture - screen capture software, including remote desktop software, may trigger content protection so disable or remove them, then restart your devices
  4. Remove display add-ons - browser add-ons or extensions related to display may trigger content protection – especially if they aren’t produced by the manufacturer devices
  5. Disable display mirroring - HDCP may sense display mirroring as a display trying to copy the video content
  6. Change the display resolution - whilst not guaranteed, some customers have reported that lowering the display resolution meant content protection did not occur

If you need to use screen sharing or display mirroring to display content, please refer to your device manufacturer for further support.

Refer to these additional articles:

What is content protection and how does it work

  1. When Digital Theatre+ publishes videos, they are encrypted.  This means that if someone downloads the video files to their computer, they cannot be played
  2. The Digital Theatre+ website includes a Video Player which uses HTML 5, and video files are distributed via the AWS Content Delivery Network, CloudFront
  3. When your browser attempts to play a video on Digital Theatre+:
    1. Your web browser starts downloading chunks of video to play
    2. Your web browser understands that the video is encrypted
    3. Your web browser requests a decryption key
    4. Our system checks that the browser should be provided a key (meaning you're signed into Digital Theatre+) and provides a decryption key that allows the video to be played
    5. Your web browser continues to download additional chunks of video as playback continues
  4. Inside your web browser is a piece of technology called the Content Decryption Module (CDM), which performs the decryption process for your web browser.  A CDM is integrated into almost all major browsers, including Safari, Chrome, Edge and Firefox.
    1. The CDM is a proprietary piece of software in the web browser that is used to decrypt video.
    2. The CDM is a "black box" which Digital Theatre+ does not and cannot control.
    3. Each browser implements it's own CDM
  5. The Video Player on the Digital Theatre+ website interacts with the CDM via a standard Browser feature - called an Encrypted Media Extensions - which is implemented in all major browsers. 

Illustration showing how these components interact

EME & CDM Illustration