Playbin stepping single frame fails on video only mp4

[Tim Müller]

On Sat, 2014-10-25 at 19:16 +0200, René Calles wrote:

Hi,

> i just came across some unexpected behavior using playbin and stepping
> though a file frame by frame.
> If my source MP4-File has an audio stream everything works as
> expected. If not, the video jumps much more than a single frame to
> front.
> 
> 
> In fact it feels like the step event steps to the current running time
> (the time the application runs) because as longer as i wait after
> setting the pipeline to the PAUSED state, the more forward jumps the
> video.
> 
> 
> The step event itself is sent with this line:
> 
> 
> gst_element_send_event(data->video_sink,
> gst_event_new_step(GST_FORMAT_BUFFERS, 1, data->rate, TRUE, FALSE));
> 
> 
> 
> 
> In both cases i receive the GST_MESSAGE_STEP_DONE message but when
> using MP4-Video without audio stream the step duration is always (at
> least as long the running time is not higher than the current video
> time) 0:00:00.000000000 and the format is at least not
> GST_FORMAT_DEFAULT.
> 
> 
> I hope someone at the list can give me any clue about this. Is it
> worth to test this behavior with different file formats so we could
> see if this may be an issue with qtdemux?

The stepping is handled by the sink(s), qtdemux doesn't even know it's
happening.

Maybe you could build a small test app that demonstrates the problem?

Cheers
 -Tim

-- 
Tim Müller, Centricular Ltd - http://www.centricular.com