Interactive annotation

[John Reilly]

My (Windows) application needs to show individual video frames, and the
user needs to position a "box" over some part of the image. I can currently
load the URI, display the frame (the pipeline is paused), and draw on it
using the cairo overlay. The pipeline looks like this:

uridecodebin uri=file:///c:/BlincRnD/EyeCloseUp.mov
   ! queue ! videoconvert ! cairooverlay name=overlay ! autovideosink
name=videoWin

Now I'm trying to do the "draw the box" part. I can get the mouse buttons
and window position using the wxWidget events. Obviously the window
coordinate is *not* the same as the frame coordinate, so I can't simply use
the mouse position without knowing the transform.

Searching these archives, I saw mention that I would need to write my own
video filter plug-in to handle the GstNavigation events. This post refers
me to the navigationtest plug-in. Using gst-inspect, I do not have the
navigationtest plug-in in my install. Where can I get it? I'd like to watch
it run.

Can anyone suggest an alternative solution for positioning my cairo drawing
on the video?

Thanks.

-reilly.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/gstreamer-devel/attachments/20160720/48eef679/attachment-0001.html>