[Bug 781998] New: Windows: directsound sink stutter

[GStreamer (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=781998

            Bug ID: 781998
           Summary: Windows: directsound sink stutter
    Classification: Platform
           Product: GStreamer
           Version: 1.10.x
                OS: Windows
            Status: NEW
          Severity: major
          Priority: Normal
         Component: gst-plugins-bad
          Assignee: gstreamer-bugs at lists.freedesktop.org
          Reporter: dustin at virtualroadside.com
        QA Contact: gstreamer-bugs at lists.freedesktop.org
     GNOME version: ---

Since forever [1], when using GStreamer on Windows if there's enough load on
the system (or various other things), playback will stutter. Other media
players on Windows (for example, Windows Media Player (WMP)) don't exhibit
these issues.

An easy way to reproduce this issue is by running Windows in a VM, and doing
things like rapidly moving around windows that change frequently (like Process
Explorer). The experiment I did today was running gst-play (msys2 gst 1.10.4)
and WMP, and comparing their performance under load.

* It's very easy to get gst-play to stutter, even under very light load
* It's much more difficult to get WMP to stutter, even under heavy load

A brief examination of the processes themselves with Process Explorer reveals
that the thread priorites in WMP are significantly higher than the thread
priorities in the gst-play process.

More digging reveals that there's a Windows API [2] for telling the system that
you're doing important multimedia processing. I theorize that if GStreamer
calls the relevant APIs when doing processing (AvSetMmThreadCharacteristics
followed by AvRevertMmThreadCharacteristics), then the performance will become
similar to WMP.

I note that Clementine has a hack to set realtime priority for OSX [3] by
setting thread priority when a GstTask is detected to start. Perhaps this is a
good place to do this? If not, where?

I'm very very interested in getting rid of this stutter issue on Windows, and
would be willing to implement/test something if someone will give me some
pointers on the best place to implement it.

I note that the Clementine audio player also has a open bug report for this
issue as well [4].

[1] https://github.com/exaile/exaile/issues/76
[2] https://msdn.microsoft.com/en-us/library/ms684247(VS.85).aspx
[3]
https://github.com/clementine-player/Clementine/commit/df21da786e74a504adbdbd74d9d7c7577c6e52ed
[4] https://github.com/clementine-player/clementine/issues/2570

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are the assignee for the bug.