[MSE][GStreamer] don't push samples while seeking #1528
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MediaSource::waitForTarget completes asynchronously. Even when the target time is already buffered, it still enqueues a task to compute seek time on next event loop cycle. This can lead to SourceBuffer providing media data for incorrect time, after GStreamer seek already flushed the source. For example this happens if TrackQueue::LowLevelHandler callback was posted just before the seek. The proposed change implements SourceBufferPrivate::isSeeking() that returns true until MSE seek is completed, effectivly blocking SourceBufferPrivate::provideMediaData during the seek.
eocanha
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https://bugs.webkit.org/show_bug.cgi?id=295415 Reviewed by NOBODY (OOPS!). MediaSource::waitForTarget completes asynchronously. Even when the target time is already buffered, it still enqueues a task to compute seek time on next event loop cycle. This can lead to SourceBuffer providing media data for incorrect time, after GStreamer seek already flushed the source. For example this happens if TrackQueue::LowLevelHandler callback was posted just before the seek. The proposed change implements SourceBufferPrivate::isSeeking() that returns true until MSE seek is completed, effectivly blocking SourceBufferPrivate::provideMediaData during the seek. See: WebPlatformForEmbedded/WPEWebKit#1528 Original author: Eugene Mutavchi <[email protected]> * Source/WebCore/platform/graphics/gstreamer/mse/MediaPlayerPrivateGStreamerMSE.cpp: (WebCore::MediaPlayerPrivateGStreamerMSE::doSeek): Signal the seek intent to the media source private. * Source/WebCore/platform/graphics/gstreamer/mse/MediaSourcePrivateGStreamer.cpp: (WebCore::MediaSourcePrivateGStreamer::willSeek): Forward the seek intent to all SourceBufferPrivates. * Source/WebCore/platform/graphics/gstreamer/mse/MediaSourcePrivateGStreamer.h: Added willSeek(). * Source/WebCore/platform/graphics/gstreamer/mse/SourceBufferPrivateGStreamer.cpp: (WebCore::SourceBufferPrivateGStreamer::willSeek): Set m_isSeeking to true. (WebCore::SourceBufferPrivateGStreamer::isSeeking const): Return m_isSeeking value. (WebCore::SourceBufferPrivateGStreamer::seekToTime): Unset m_isSeeking and call the default SourceBufferPrivate seekToTime() implementation. * Source/WebCore/platform/graphics/gstreamer/mse/SourceBufferPrivateGStreamer.h: Added willSeek(), isSeeking(), seekToTime() and the m_isSeeking flag.
eocanha
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Submitted the patch for upstream review as https://bugs.webkit.org/show_bug.cgi?id=295415 / WebKit/WebKit#47564 |
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Hi @eocanha, any progress here? |
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It's still pending for upstream review, but the reviewer with the most appropriate knowledge to review it is currently busy with a higher priority performance regression in wpe-2.46. |
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Thanks for the update @eocanha |
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MediaSource::waitForTarget completes asynchronously. Even when the target time is already buffered, it still enqueues a task to compute seek time on next event loop cycle. This can lead to SourceBuffer providing media data for incorrect time, after GStreamer seek already flushed the source. For example this happens if
TrackQueue::LowLevelHandler callback was posted just before the seek.
The proposed change implements SourceBufferPrivate::isSeeking() that returns true until MSE seek is completed, effectivly blocking SourceBufferPrivate::provideMediaData during the seek.