Pause MediaPlayerElement when leaving the live tree by Hemantxk · Pull Request #11670 · microsoft/microsoft-ui-xaml

Hemant Kumar (Hemantxk) · 2026-08-27T11:52:10Z

Fixes

PR Type

Description

Current Behavior

When a Window containing a playing MediaPlayerElement is closed, its visual tree is torn down. If the app still retains the closed Window or MediaPlayerElement, the underlying MediaPlayer also remains alive and keeps playing. The video surface disappears with the Window, but its audio continues in the background.

New Behavior

When MediaPlayerElement leaves the live visual tree:

A playing or buffering MediaPlayer is paused.
Transient visual-tree resets are ignored unless the element's ContentRoot is shutting down.
The element records whether it successfully initiated the pause.
If the same element later re-enters the live tree, it resumes only when it initiated that pause.
Replacing the assigned MediaPlayer clears the pending resume state.
Resume failures are logged with LOG_IF_FAILED without failing tree entry.

Customer Impact

Closing or removing playback UI no longer leaves invisible media continuing in the background. If the same element is temporarily removed and later reattached, its previous playback continues automatically only when the element caused the pause.

There is no public API change.

Regression Potential

The change is limited to live-tree leave/re-entry handling. It pauses only a player that is currently playing or buffering, skips transient tree resets, and resumes only after a successful framework-initiated pause.

Low risk — isolated change, limited scope
Medium risk — touches shared components or public APIs
High risk — architectural or breaking API change

How Has This Been Tested?

Focused WPF TAEF tests:

PausesAndResumesMediaPlayerWhenRemovedFromTree — passed
PausesMediaPlayerWhenWindowCloses — passed

Result: 2 passed, 0 failed, 0 blocked.

Manual retained-Window validation confirmed that closing the playback Window stops its audio while the Window remains retained. Collapsing only the element's visibility continues playback, as expected, because it remains in the live tree.

This commit restores the behavior covered by those passing tests. The latest amd64fre Microsoft.ui.xaml.vcxproj build completed with 0 warnings and 0 errors. Per request, the tests were not rerun.

I have performed a self-review of my own code
I have added tests to cover my changes
Existing tests pass locally

Screenshots (if appropriate)

N/A — this is a playback lifecycle behavior change with no visual UI change.

Pause a playing MediaPlayer when its element leaves the live tree and resume only when that element initiated the pause. Cover remove/re-entry and retained Window-close lifecycles. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: a3043399-4002-4d60-b928-b71920a36bf0

azure-pipelines · 2026-08-27T11:52:18Z

Azure Pipelines: There may be pipelines that require an authorized user to comment /azp run to run.

Pause only when the element leaves because its ContentRoot is shutting down. Remove resume state and retain focused Window-close coverage. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: a3043399-4002-4d60-b928-b71920a36bf0

Keep a source token after the final event macro expansion without retaining the temporary undef directives. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: a3043399-4002-4d60-b928-b71920a36bf0

Pause playing media on live-tree leave and resume when the same element re-enters after initiating that pause. Restore both focused lifecycle tests. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: a3043399-4002-4d60-b928-b71920a36bf0

azure-pipelines · 2026-08-27T13:22:21Z

Azure Pipelines: There may be pipelines that require an authorized user to comment /azp run to run.

Hemant Kumar (Hemantxk) · 2026-08-27T13:22:49Z

/azp run

azure-pipelines · 2026-08-27T13:22:56Z

Azure Pipelines: 1 pipeline(s) were filtered out due to trigger conditions.

Preserve the original trailing blank line after the final event macro expansion. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: a3043399-4002-4d60-b928-b71920a36bf0

Harini Malothu (HariniMalothu17) · 2026-08-27T13:40:31Z

/azp run

azure-pipelines · 2026-08-27T13:40:38Z

Azure Pipelines: 1 pipeline(s) were filtered out due to trigger conditions.

Godly T.Alias (godlytalias) · 2026-08-27T14:04:04Z

        IFC_RETURN(m_spTimedTextSource->SetMediaPlayer(nullptr));
    }

+    bool shouldPauseMediaPlayer = bLive && !bVisualTreeBeingReset;


shouldPauseMediaPlayer = bLive && !bVisualTreeBeingReset means we pause on every ordinary removal from the live tree, not just on a window close - Frame navigation, ListView/ItemsRepeater container recycling, TabView content swap, re-parenting and Popup close all take this path. The linked bug is scoped to a terminal close, so we may have to consult IsShuttingDown() on both branches rather than treating !bVisualTreeBeingReset as sufficient. Please check whether the non-reset path should be pausing at all.

Godly T.Alias (godlytalias) · 2026-08-27T14:04:22Z

+
    IFC_RETURN(__super::LeaveImpl(bLive, bSkipNameRegistration, bCoercedIsEnabled, bVisualTreeBeingReset));

+    if (shouldPauseMediaPlayer && m_spMediaPlayer && !m_resumeMediaPlayerOnEnter)


Since e88e20cc removed m_bOwnsMediaPlayer there is no ownership signal left on the class, so this also pauses app-supplied players and players shared with a second MediaPlayerElement that is still live and on screen. SharedMediaPlayerSurvivesElementDestruction only pins the destruction path, so a shared player being paused by whichever element leaves first would not be caught. Please check whether we need a framework-created-player signal before mutating transport state here.

Godly T.Alias (godlytalias) · 2026-08-27T14:04:37Z

    {
        IFC_RETURN(UpdateAutoPlay());

+        if (m_resumeMediaPlayerOnEnter && m_spMediaPlayer)


m_resumeMediaPlayerOnEnter is only cleared at line 267 for the MediaPlayer property and here at 706, so a Source change while the element is detached leaves it set and we force a Play() on the newly bound content on re-entry - that is the recycled container case for ListView and ItemsRepeater. It also bypasses AutoPlay="False", since UpdateAutoPlay() runs just before this, and it reverses a Pause() the app or user performed while we were out of the tree. Please check whether we should clear the flag in the Source case too, and re-read PlaybackState before resuming.

Godly T.Alias (godlytalias) · 2026-08-27T14:07:24Z

+    bool shouldPauseMediaPlayer = bLive && !bVisualTreeBeingReset;
+    if (bLive && bVisualTreeBeingReset)
+    {
+        if (CContentRoot* contentRoot = VisualTree::GetContentRootForElement(GetHandle()))


If GetContentRootForElement returns null here we fall through with shouldPauseMediaPlayer still false from line 731, so the one branch that actually implements the fix quietly does nothing and the bug reproduces with no assert or trace to explain why. Please check whether treating an unresolved content root as shutting down would be the safer default on a path we already know is a tree reset.

microsoft-github-policy-service Bot added the needs-triage Issue needs to be triaged by the area owners label Aug 27, 2026

Hemant Kumar (Hemantxk) and others added 3 commits August 27, 2026 17:39

Avoid end-of-file macro warning

7a20557

Keep a source token after the final event macro expansion without retaining the temporary undef directives. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: a3043399-4002-4d60-b928-b71920a36bf0

Hemant Kumar (Hemantxk) marked this pull request as ready for review August 27, 2026 13:22

Hemant Kumar (Hemantxk) requested a review from a team as a code owner August 27, 2026 13:22

Restore MediaPlayerElement source file ending

532ce74

Preserve the original trailing blank line after the final event macro expansion. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: a3043399-4002-4d60-b928-b71920a36bf0

Godly T.Alias (godlytalias) reviewed Aug 27, 2026

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Pause MediaPlayerElement when leaving the live tree - #11670

Pause MediaPlayerElement when leaving the live tree#11670
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Hemant Kumar (Hemantxk) commented Aug 27, 2026 •

edited

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		IFC_RETURN(__super::LeaveImpl(bLive, bSkipNameRegistration, bCoercedIsEnabled, bVisualTreeBeingReset));

		if (shouldPauseMediaPlayer && m_spMediaPlayer && !m_resumeMediaPlayerOnEnter)

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Fixes

PR Type

Description

Current Behavior

New Behavior

Customer Impact

Regression Potential

How Has This Been Tested?

Screenshots (if appropriate)

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Hemant Kumar (Hemantxk) commented Aug 27, 2026 •

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