GStreamer 1.6 and OpenGL contexts
With the imminent release of GStreamer 1.6 there has been a change in the mechanism by which OpenGL contexts and Window System (X11, Wayland, Win32, OS X's Cocoa) specific resources are shared with a GStreamer pipeline for elements that need that information. Elements like sinks or any of the GL elements or any global application provided information that is shared between elements. Previously, in 1.4, there was a property, 'external-opengl-context' available on some(!) elements that one could set on the current set of filter and mixer elements (not sink or source elements though!). While it mostly worked well enough, it was a behaviour difference to how window system handles are shared between the application and the GStreamer pipeline. Internal GL context sharing between elements was occurring in the ALLOCATION query as a value in a GstStructure of the meta:GstVideoGLTextureUploadMeta parameters. The main problem with this is 1. the ALLOCATION query is handled diffe...