[mythtv] [PATCH] Workaround for hangs when ffwd/rewinding video

[Paul Andreassen]

On Mon, 25 Sep 2006 08:17 pm, Paul Andreassen wrote:
> On Thu, 21 Sep 2006 05:58 am, Matt Holgate wrote:
> > I'm running myth-0.20-fixes on a VIA EPIA M10000 box, and I get
> > regularly get hangs while fast forwarding/rewinding videos (live tv or
> > recorded).
> >
> > It seems to happen when seeking then resuming playback. In the logs I
> > get loads of messages like:
> >
> > 2006-09-20 20:40:27.917 Waited too long for video out to pause
> >
> > I've seen other people point out this issue too. Tracing it back, it
> > seems to be getting stuck in PauseVideo():
> >
> > #0  0xb5df3440 in pthread_cond_timedwait@@GLIBC_2.3.2 () from
> > /lib/tls/libpthread.so.0
> > #1  0xb64e04e0 in QWaitCondition::wait () from /usr/lib/libqt-mt.so.3
> > #2  0xb792fcba in NuppelVideoPlayer::PauseVideo (this=0x8f32db0,
> > wait=true) at NuppelVideoPlayer.cpp:456
> > #3  0xb7943448 in NuppelVideoPlayer::StartPlaying (this=0x8f32db0)
> >      at NuppelVideoPlayer.cpp:3317
> > #4  0xb78deedf in SpawnDecode (param=0x8f32db0) at tv_play.cpp:256
> > #5  0xb5df0b63 in start_thread () from /lib/tls/libpthread.so.0
> > #6  0xb5ca918a in clone () from /lib/tls/libc.so.6
> >
> > I think what is happening is that the seeking operation is trying to
> > pause the video:
> >
> >             if (fftime >= 5)
> >              {
> >                  PauseVideo();
> >
> > but there is a race between PauseVideo() setting the pausevideo member
> > to true:
> >
> > void NuppelVideoPlayer::PauseVideo(bool wait)
> > {
> >      video_actually_paused = false;
> >      pausevideo = true;
> >
> > and the user pressing 'play' causing pausevideo to become false in
> > UnpauseVideo()
> >
> >
> > void NuppelVideoPlayer::UnpauseVideo(void)
> > {
> >      pausevideo = false;
> > }
> >
> > I think this is causing PauseVideo to get stuck in an infinite loop will
> > trying to seek.
> >
> > I've attached a patch which works around this, but I've no idea if it's
> > the correct thing to do. If you think it seems sensible, I'll open a
> > ticket and submit it properly. Feedback please :)
> >
> > thanks a lot,
> > Matt.
>
> Hi Matt,
>
> Thanks for the patch.  I've trained myself not to change directions while
> fast forwarding, just so my M10000 wont lockup and require a keyboard
> mythfrontend restart.  With this patch it doesn't seem to be a problem
> anymore.
>
> Thanks again,
> Paul

I've just noticed that I can no longer pause and move frame by frame.

Paul
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