Make gstreamer render even when there is no video streaming

[Tim Müller]

On Thu, 2014-09-18 at 19:10 +0200, Wizardy wrote:

Hi,

> I'm developing a client application where I use gstreamer to get a
> video streaming from another device and display it along with some
> extra information (text and images). To render all the information
> over the video I'm using the cairo plugin included with gstreamer
> which works great. The problem I'm having is the video streaming is
> not always available, and when it isn't gstreamer doesn't render
> anything, so all my extra information isn't shown either.
> 
> A simplified version of my pipeline:
> 
> udpsrc port=5000 ! application/x-rtp, payload=96 ! rtph264depay !
> avdec_h264 ! videoconvert ! cairooverlay ! videoconvert ! d3dvideosink
> 
> Does someone know how can I make gstreamer render cairo even when
> there is no video?

I think you broadly have two options:

1) do the overlaying outside of GStreamer using your graphics system

2) you could do something like:

  udpsrc ! ... ! dec ! intervideosink

  intervideosrc ! cairooverlay ! videoconvert ! d3dvideosink

and intervideosrc will continue to output the last buffer or (after a
while without signal) a black buffer

 Cheers
  -Tim


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