No video is displayed yet audio can be heard

This article explains what to do if you do not see any video yet the audio can be heard playing

Digital Theatre+ uses Digital Rights Management (DRM) protection  so that videos are only being played by users who are authorised to play them and to prevent unauthorised copying of videos. 

If you experience an issue where the video player displays a solid black image, yet the video appears to be playing and audio can be heard, then it's likely that your monitor, browser or operating system has not passed the necessary checks to allow the video to be displayed on your device.

This issue can also be exhibited if you try and share the video playback over a Web Conferencing tool such as Zoom, Microsoft Teams or Google Meet.  In this situation, the host will see video and hear sound, however meeting attendees will only hear sound and will not see video.  See below for recommendations of how to share video in online classes.

Screenshot of how this issue may appear

Screenshot 2021-03-29 at 11.30.14

Recommended troubleshooting steps

  1. Try using a different web browser, such as Chrome or Edge.  Safari appears to suffer this issue the most, so avoid using that browser for video playback.
  2. Ensure that the external device (monitor or projector) you're attempting to play on supports High-bandwidth Digital Content Protection (HDCP).
  3. Ensure that your operating system is not allowing your browser to perform screen recording.


If you are using an unsupported monitor, try the following:

  • If using a laptop with an external monitor, disconnect the external monitor or switch to an HDCP compliant cable and monitor.
  • If using a desktop, ensure that:
    • your cable is either HDMI or DVI
    • your monitor is HDCP compliant (analog cords, such as VGA, are not HDCP compliant.)
    • the output resolution is at least 1920 x 1080 pixels
    • you disconnect any other devices (e.g. additional monitors or video outputs)


  • Ensure the source device is connected to the projector using a digital connection either HDMI or DVI cables
  • Ensure the output video resolution is at least 1920 x 1080 pixels
  • Ensure the screen is mirrored (rather than being set to use the video output as an additional desktop/extended)
  • Disconnect any other devices (e.g. additional monitors or video outputs)
  • Try swapping the HDMI or DVI cable in case it is faulty

Projectors will usually have a tag or sticker that states that the projector is HDCP compliant. Some manufacturers may add a sticker to packaging stating ‘HDMI Compliant.’

An error may occur on your device if it is not compliant. 

Recommendations for showing videos in an online class

Our videos may not allow you to share them via a Web Conferencing tool if the tool is not compliant with content protection standards.

Do not attempt to stream video using Web Conferencing tools

We recommend avoiding streaming any videos via sharing within a Web Conferencing tool, as this is likely to create an unsatisfactory experience for attendees.   

Videos shared in this way are subject to the constraints of the computer being used including the network bandwidth for both download and upload.

Also, rather than stream directly from the nearest low latency content delivery network endpoint to the viewer, the video is compressed on the computer, transported via the Web Conferencing tools own servers and networks and then re-distributed by the Web Conferencing tools systems.

Following is an illustration of how this erodes the quality of playback and experience.

Streaming via web conferencing

We recommend streaming via our Content Delivery Network direct to your viewers

By allowing your viewers to stream the video directly from Digital Theatre+ to their own computers, the constraints and issues mentioned before are resolved.

Streaming video via optimised CDN

Whilst doing this may create a co-ordination challenge, we believe the benefit of each attendee receiving a high quality stream are worth it.  Some suggestions to over-come this co-ordination challenge are:

  • Distribute the URL to the video and ask students watch the video on their own, before the class. Class time may then be spent discussing the video.
  • For Segments you wish to watch during the class, click on the link to the Segment (the URL in the address bar will end with ?start=1165&end=1430); copy the URL and paste it into the class chat or stream.  Ask students to watch the video on their own computer (and mute themselves) and then re-join the class for discussion after the duration of the video.
  • For longer videos, ask student to start the video at the same time and provide a list of pause times that you want students to re-join the class for discussion. 

You can create URLs to videos that start and stop at specific time points by appending ?start=<seconds>&end=<seconds> to the URL, replacing <seconds> with the number of seconds you wish video playback to start and end with.  With a little preparation, you can create a series of links to the sections of video you are most interested in.

For example:

More information about our Content Delivery Network

We distribute our video via Amazon CloudFront. Amazon CloudFront peers with thousands of Tier 1/2/3 telecom carriers globally, is well connected with all major access networks for optimal performance, and has hundreds of terabits of deployed capacity.

To deliver content to end users with lower latency, Amazon CloudFront uses a global network of 225+ Points of Presence (215+ Edge locations and 13 regional mid-tier caches) in 90 cities across 47 countries. Amazon CloudFront Edge locations are located in:

Amazon CloudFront Edge Locations

North America
Edge locations: Ashburn, VA (6); Atlanta, GA (6); Boston, MA (3); Chicago, IL (6); Dallas/Fort Worth, TX (6); Denver, CO (2); Hayward, CA; Hillsboro, OR (3); Houston, TX (4); Jacksonville, FL; Los Angeles, CA (5); Miami, FL (4); Minneapolis, MN; Montreal, QC; New York, NY (2); Newark, NJ (7); Palo Alto, CA; Philadelphia, PA (2); Phoenix, AZ (2); Salt Lake City, Utah; San Jose, CA (2); Seattle, WA (3); Toronto, ON (2); Vancouver, BC ; Querétaro, MX (2)

Regional Edge caches: California; Ohio; Oregon; Virginia;

Edge locations: Amsterdam, The Netherlands (2); Athens, Greece; Berlin, Germany (2); Brussels, Belgium; Bucharest, Romania; Budapest, Hungary; Copenhagen, Denmark; Dublin, Ireland; Dusseldorf, Germany; Frankfurt, Germany (10); Hamburg, Germany; Helsinki, Finland; Lisbon, Portugal; London, England (9); Madrid, Spain (3); Manchester, England (2); Marseille, France; Milan, Italy (3); Munich, Germany (2); Oslo, Norway; Palermo, Italy; Paris, France (5); Prague, Czech Republic; Rome, Italy; Sofia, Bulgaria; Stockholm, Sweden (3); Vienna, Austria; Warsaw, Poland; Zagreb, Croatia; Zurich, Switzerland (2)

Regional Edge caches: Dublin, Ireland; Frankfurt, Germany; London, England

Edge locations: Bangalore, India (3); Bangkok, Thailand (2); Chennai, India (4); Hong Kong, China (3); Hyderabad, India (3); Jakarta, Indonesia; Kolkata, India (2); Kuala Lumpur, Malaysia (2); Mumbai, India (4); Manila, Philippines; New Delhi, India (5); Osaka, Japan; Seoul, South Korea (4); Singapore (4); Taipei, Taiwan(3); Tokyo, Japan (16)

Regional Edge caches: Mumbai, India; Singapore; Seoul, South Korea; Tokyo, Japan

Australia & New Zealand
Edge locations: Auckland, NZ (2); Melbourne, AU (2); Perth, AU; Sydney, AU (4); 

Regional Edge caches: Sydney

South America
Edge locations: Bogota, Colombia; Buenos Aires, Argentina; Rio de Janeiro, Brazil (2); Santiago, Chile; São Paulo, Brazil (2)

Regional Edge caches: São Paulo, Brazil

Middle East
Edge location: Dubai, United Arab Emirates; Fujairah, United Arab Emirates; Manama, Bahrain; Tel Aviv, Israel

Edge locations: Cape Town, South Africa; Johannesburg, South Africa; Nairobi, Kenya

Edge locations: Beijing; Shenzhen; Shanghai; Zhongwei

Further information about Amazon CloudFront can be found on the Key Features page on Amazon's website.