Sharing EGL context with glimagesink

Jorge Fernandez Monteagudo jorgefm at
Wed Oct 7 07:51:06 PDT 2015

Thanks Matt! The note do the trick :)

I was using GST_GL_API_GLES1 API. I've converted my little app to ES2.0 and now it works...
Well I've to paint the glimagesink texture in the 'client-draw' callback but it works. Now I'll try to
found a way to save the texture and paint it in my drawing loop.

From: Matthew Waters [ystreet00 at]
Sent: Wednesday, October 07, 2015 4:27 AM
To: Jorge Fernandez Monteagudo; gstreamer-devel at
Subject: Re: Sharing EGL context with glimagesink

On 06/10/15 23:52, Jorge Fernandez Monteagudo wrote:


I'm trying to share the main EGL context from my application and the glimagesink element
from the pipeline I'm implementing, using the 'other-context' field. I'm trying to paint the
texture with the video frame with my code.

glimagesink in 1.6 does not have an 'other-context' property anymore and so that information needs to be provided with GstContext. See <> for the details.

Now I have the next vars initialized ok (I can paint using gl commands)

EGLDisplay dpy;
EGLSurface surface;
EGLContext context;

The question is if you can actually simply use the EGLDisplay without first going through the winsys, wayland/X11/dispmanx/etc.  Android is the only platform that I know of that will allow using the EGLDisplay natively without first having an existing display connection.  Essentially you must pass the winsys display handle if you have it over the EGLDisplay handle.

and the 'eglMakeCurrent(dpy, surface, surface, context)' call returns success.
Then I set up the pipeline and the glimagesink with:

  GstGLDisplay *glDisplay;
  GstGLContext *glContext;

  // Set glimagesink gl context.
  glDisplay = (GstGLDisplay *)gst_gl_display_egl_new_with_egl_display( dpy );
  glContext = gst_gl_context_new_wrapped( glDisplay, (guintptr) context, GST_GL_PLATFORM_EGL, GST_GL_API_GLES1 );

Just a note that we don't actually support the GST_GL_API_GLES1 API.  If you're actually using GLES1-only api calls I'm afraid this will not work at all.

That should help you along the way.


  g_object_set( G_OBJECT(glimagesink), "other-context", glContext, NULL );
  eglMakeCurrent( dpy, surface, surface, context );
  printf( "glDisplay=%p   glContext=%p\n", glDisplay, glContext );

When I run the code I see the printf trace

glDisplay=0x24c78   glContext=0x255848

and the backtrace

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x713fc460 (LWP 15929)]
__glInitFramebufferStates (gc=gc at entry=0x37b2ec) at src/glcore/gc_es_fbo.c:998
998     src/glcore/gc_es_fbo.c: No such file or directory.
(gdb) bt
#0  __glInitFramebufferStates (gc=gc at entry=0x37b2ec) at src/glcore/gc_es_fbo.c:998
#1  0x768cba1c in __glInitContextState (gc=gc at entry=0x37b2ec) at src/glcore/gc_es_context.c:702
#2  0x768cc048 in __glCreateContext (clientVersion=<optimized out>, imports=0x713fbc88, sharedCtx=0x22e974) at src/glcore/gc_es_context.c:1043
#3  0x76d1b504 in _CreateApiContext (Thread=Thread at entry=0x262204, Context=Context at entry=0x37b1cc, Config=0x1b5f0c, Config at entry=0x31be, SharedContext=0x22e974)
    at gc_egl_context.c:593
#4  0x76d1bdf4 in eglCreateContext (Dpy=0x1b4204, config=<optimized out>, SharedContext=0x1b77dc, attrib_list=0x713fbd6c) at gc_egl_context.c:1385
Backtrace stopped: Cannot access memory at address 0x302a

Any hint?


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