Bug 224235 - [GStreamer] Only seek to change the rate un updatePlaybackRate() when needed
Summary: [GStreamer] Only seek to change the rate un updatePlaybackRate() when needed
Alias: None
Product: WebKit
Classification: Unclassified
Component: WebKitGTK (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Enrique Ocaña
Depends on:
Reported: 2021-04-06 06:45 PDT by Enrique Ocaña
Modified: 2021-04-07 02:10 PDT (History)
14 users (show)

See Also:

Patch (3.10 KB, patch)
2021-04-06 08:45 PDT, Enrique Ocaña
no flags Details | Formatted Diff | Diff
Patch (3.91 KB, patch)
2021-04-06 09:39 PDT, Enrique Ocaña
no flags Details | Formatted Diff | Diff

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Description Enrique Ocaña 2021-04-06 06:45:10 PDT
A seek is used by MediaPlayerPrivateGStreamer to update the playback rate used in the pipeline. There's a special case when the rate is 0.0. This actually means "paused" and, when set, the pipeline is changed to PAUSED and no updatePlaybackRate() call is made because of an early return (and therefore, no seek). When the rate is restored to a non-zero value, the pipeline is set again to PLAYING, but an unconditional call to updatePlaybackRate() is done, leading to a seek.

It should be possible to call updatePlaybackRate() only if the non-zero rate changed with respect to the original one, instead of always doing it. This would avoid unneeded seeks, which are complex operations that can trigger collateral issues such as the one addressed in https://bugs.webkit.org/show_bug.cgi?id=223742.
Comment 1 Enrique Ocaña 2021-04-06 08:45:17 PDT
Created attachment 425284 [details]
Comment 2 Alicia Boya García 2021-04-06 09:16:51 PDT
Comment on attachment 425284 [details]

View in context: https://bugs.webkit.org/attachment.cgi?id=425284&action=review


> Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamer.cpp:539
> +            m_lastPlaybackRate = m_playbackRate;

Add a documentation comment in the header file explaining this means the last playback rate sent through a GStreamer seek.
Comment 3 Enrique Ocaña 2021-04-06 09:39:18 PDT
Created attachment 425288 [details]
Comment 4 EWS 2021-04-07 02:10:16 PDT
Committed r275596: <https://commits.webkit.org/r275596>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 425288 [details].