How to crop video on Android/Gstreamer with glimagesink

[Gregoire Gentil]

Hello,

I would like to crop the rendering of a video playback in Android which 
uses glimagesink.

I can do the job by inserting a videocrop element before glimagesink but 
I would like to achieve the same goal by using the "render-rectangle" 
property of glimagesink - the objective is that the crop operation is 
done by the GPU, not the CPU. That doesn't work. 
gst_video_overlay_set_render_rectangle doesn't work either.

Am I missing something?

Thanks in advance,

Grégoire