Why are all my seek events ignored?

[Nikos Chantziaras]

That doesn't work either. If I do:

   pipeline->setState(QGst::StatePlaying);
   pipeline->sendEvent(seekEv);

without waiting with a getState() first before sending the event, the 
seek has no effect. I assume that due to all calls being asynchronous, 
the state has not transitioned yet from StateNull to StatePlaying when 
the event gets sent. But I don't know for sure, since I'm not familiar 
with the gstreamer internals.


On 16/02/15 06:06, Duncan Palmer wrote:
> I'd say there's something else wrong there. You can certainly send a
> seek event to set the position whilst the pipeline is PLAYING, and I
> can't see why changing the speed should make any difference.
>
> On 16 February 2015 at 13:42, Nikos Chantziaras <realnc at gmail.com
> <mailto:realnc at gmail.com>> wrote:
>
>     On 13/02/15 23:17, Nikos Chantziaras wrote:
>
>         I'm trying to send a seek event to a pipeline to make the video
>         play at
>         half speed with:
>
>             QGst::SeekEventPtr seekEv = QGst::SeekEvent::create(
>               0.5,
>               QGst::FormatTime,
>               QGst::SeekFlagSegment,
>               QGst::SeekTypeSet, 0,
>               QGst::SeekTypeEnd, 0);
>
>             pipeline->sendEvent(seekEv);
>             pipeline->setState(QGst::__StatePlaying);
>
>         But it gets ignored. The video plays at 100% speed. In fact, my bus
>         message handler doesn't even receive a single
>         QGst::MessageSegmentDone
>         message.
>
>
>     OK, figured it out. For anyone who comes across the same problem, it
>     is crucial to:
>
>        a. Set the SeekFlagFlush flag on the event
>        b. Put the pipeline into the paused state before sending the event
>        c. Wait for the state change to complete before sending the event
>
>     Although not crucial, using SeekTypeNone for the stop type and
>     GST_CLOCK_TIME_NONE for the stop time seems to be a good idea.
>
>     So:
>
>        QGst::SeekEventPtr seekEv = QGst::SeekEvent::create(
>            0.5,
>            QGst::FormatTime,
>            QGst::SeekFlagFlush,
>            QGst::SeekTypeSet, 0,
>            QGst::SeekTypeNone, GST_CLOCK_TIME_NONE);
>
>        pipeline->setState(QGst::__StatePaused);
>        pipeline->getState(0, 0, GST_CLOCK_TIME_NONE); // wait for pause
>     state
>        pipeline->sendEvent(seekEv);
>        pipeline->setState(QGst::__StatePlaying);
>
>     This worked correctly.