Video glitches when playhead within buffered region with overlapping video renditions

Needs root cause Issue #14600375 • Assigned to Nishant N.


Nov 10, 2017
This issue is public.
Found in
  • Microsoft Edge
Found in build #
Needs root cause
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Reported by 4 people

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Steps to reproduce

When playing back video content in Edge using MSE and switching renditions, if the playhead reaches a portion of the buffer where the renditions are overlapping, the video will freeze while audio plays, then playback will alternate between frozen audio and video for a few seconds before the content resumes with appropriate sync

Similar issues have been noted in some open source projects for IE11, including dash.js with its use of "fastSwitchEnabled":

“In IE11 with auto switching off, if a user switches to a quality they can not download in time the fragment may be appended in the same range as the playhead or even in the past, in IE11 it may cause a stutter or stall in playback.” (see

The following steps can be taken to see the behavior:

  1. Visit either the dash.js demo page, or the shaka player demo page,;lang=en-US
  2. If using the dash.js demo page, ensure under the “options” (button) that “Fast Switching ABR” is checked (this sets “fastSwitchEnabled” to true). This should be the default.
  3. Load the first video (or any of the sample videos).
  4. Use the rendition selector to select a low bitrate.
  5. Immediately switch to a high bitrate.
  6. As the rendition changes, watch for playback issues described above.

It may be necessary to partially throttle the internet connection, or to be fast on the rendition switch, to ensure that the playhead reaches the overlapping content, but it happens more often than not.

Thank you.

Microsoft Edge 41.16299.15.0
Microsoft EdgeHTML 16.16299


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    Comments and activity

    • Microsoft Edge Team

      Changed Assigned To to “James M.”

    • Hello,

      Thank you for providing your feedback on IE11. We are not accepting feedback on Internet Explorer through this portal any longer (unless security related). We welcome any feedback you have on Microsoft Edge through this website.

      Best Wishes,
      The MS Edge Team

    • Hi James,

      Please note that the bug also mentions specifically that this issue affects Edge, too.

      “When playing back video content in Edge using MSE…”
      “Microsoft Edge 41.16299.15.0”
      “Microsoft EdgeHTML 16.16299”

    • Microsoft Edge Team

      Changed Assigned To to “Venkat K.”

      Changed Assigned To from “Venkat K.” to “Nishant N.”

      Changed Status to “Needs root cause”

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