[FFmpeg-devel] [PATCH] FFplay speedup if stepping whilst paused

[Michael Niedermayer]

Hi

On Fri, Aug 03, 2007 at 11:18:17AM +0100, Craig Nicol wrote:
> On 8/2/07, Michael Niedermayer <michaelni at gmx.at> wrote:
> > Hi
> >
> > On Thu, Aug 02, 2007 at 11:39:52AM +0100, Craig Nicol wrote:
> > > I've been writing a drift-correction program based on ffplay.c, but I've
> > > discovered a problem in the original ffplay code that is still in the latest
> > > SVN I've only tested this under Windows (MinGW), but given the patch that
> > > fixes it below, I assume this is common to all platforms. The problem should
> > > be repeatable by:
> > >
> > > 1. Open a video file in ffplay (I've used MPEG and an AVI recorded from
> > > SecondLife)
> > > 2. Pause the playing video by pressing space (or press s, which also causes
> > > a pause)
> > > 3. Step forward a frame by pressing s
> > > 4. Wait a few seconds
> > > 5. Unpause the video by pressing space
> > >
> > > Expected Behaviour:
> > > Video should continue at normal speed.
> > >
> > > Actual Behaviour:
> > > Video speeds up to catch-up with the 'lost' few seconds.
> > >
> > > The audio stream appears to pause and restart correctly. I have not tested
> > > this on videos with subtitles.
> > >
> > > Patch behaviour:
> > > Uses the existing stream_pause() function within the step frame code to
> > > maintain the correct state whether paused using 's' or the space key.
> > >
> > > Suggested commit message:
> > > Corrected pause handling when using the 's' step by frame key.
> > > --
> > > skype: callto:craignicol     sip:craignicol at ekiga.net
> >
> > > Index: ffplay.c
> > > ===================================================================
> > > --- ffplay.c  (revision 9868)
> > > +++ ffplay.c  (working copy)
> > > @@ -2213,7 +2213,7 @@
> > >  {
> > >      if (cur_stream) {
> > >          if (cur_stream->paused)
> > > -            cur_stream->paused=0;
> > > +            stream_pause(cur_stream);
> > >          cur_stream->video_current_pts = get_video_clock(cur_stream);
> >
> > shouldnt the
> > cur_stream->video_current_pts=  ...
> > be removed ?
> >
> I didn't remove it in the code I'm working with, and it works
> properly. What behaviour would you expect to change if that line was
> removed?

none, thats why i think it should be removed :)

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Concerning the gods, I have no means of knowing whether they exist or not
or of what sort they may be, because of the obscurity of the subject, and
the brevity of human life -- Protagoras
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