push opengl texture to gstreamer pipeline
Matthew Waters
ystreet00 at gmail.com
Thu Aug 5 08:39:18 UTC 2021
So, I think you almost have the correct sequence.
Response inline.
On 5/8/21 1:04 am, Lusine Hayrapetyan via gstreamer-devel wrote:
> Hi Folks,
> I'm struggling with the following issue and can't understand what I'm
> doing wrong.
> I need to pass opengl texture to the gstreamer pipeline.
> I have a rendering thread where I create opengl texture, the following
> objects created in this thread:
> /EGLDisplay display;/
> /EGLContext context;/
> /
> /
> I create gstreamer pipeline in the main thread and as described in the
> following article sharing an X11 display and GstGLContext with the bus
> callback.
> http://ystreet00.blogspot.com/2015/09/gstreamer-16-and-opengl-contexts.html
> <http://ystreet00.blogspot.com/2015/09/gstreamer-16-and-opengl-contexts.html>
>
> GstGLDisplayEGL and GstGLContext are created in this way:
> /GstGLDisplayEGL* gst_display =
> gst_gl_display_egl_new_with_egl_display (display);
> /
> /GstGLContext *gl_context =
> gst_gl_context_new_wrapped (GST_GL_DISPLAY (gst_display),
> (guintptr) context, GST_GL_PLATFORM_EGL, GST_GL_API_GLES2);/
>
> The first element of my pipeline is appsrc:
> /appsrc stream-type=0 emit-signals=1 format=3
> caps=video/x-raw(memory:GLMemory), width=300, height=300,
> framerate=(fraction)20/1, format=(string)RGBA ! gldownload ! .../
>
> I use need-data callback to create a buffer from texture_id and and
> push it in the appsrc:
> /g_signal_connect (state->appsrc, "need-data", G_CALLBACK (/ pushFrame
> /), state);/
> /
> /
> /bool pushFrame()/
> /{
> // Wrap the texture into GstGLMemory
> GstVideoInfo vinfo;
> gst_video_info_set_format(&vinfo, GST_VIDEO_FORMAT_RGBA, 300, 300);
>
> GstAllocator* allocator =
> GST_ALLOCATOR(gst_gl_memory_allocator_get_default(gl_context));
>
> GstGLVideoAllocationParams* params =
> gst_gl_video_allocation_params_new_wrapped_texture(
> state->gl_context, NULL, &vinfo, 0, NULL,
> GST_GL_TEXTURE_TARGET_2D, GST_GL_RGBA, / texture_id /,
> NULL, 0);
> /
The use of state->gl_context is probably your OpenGL context that has
been wrapped from the application. This 'wrapped' OpenGL context has
some limitations, one being that GStreamer cannot actually do a complete
gst_gl_context_thread_add where the request is marshalled to an
OpenGL-specific thread. This is what that critical is complaining about
effectively.
To do this properly, you would need to do one of two things:
1. Retrieve the OpenGL context from the downstream gldownload element
using either the 'context' property or using an appropriate GST_CONTEXT
QUERY or the helper gst_gl_query_local_gl_context().
2. Create your own GStreamer OpenGL context and add it to the
GstGLDisplay using something like:
https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/blob/master/gst-libs/gst/gl/gstglbasefilter.c#L550-565
<https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/blob/master/gst-libs/gst/gl/gstglbasefilter.c#L550-565>.
Cheers
-Matt
> /
> // The following line produces an error!!!
> GstGLMemory* glMemory = GST_GL_MEMORY_CAST(gst_gl_base_memory_alloc(
> GST_GL_BASE_MEMORY_ALLOCATOR_CAST(allocator),
> (GstGLAllocationParams*) params));
>
> gst_gl_allocation_params_free((GstGLAllocationParams *)params);
> gst_object_unref(allocator);
>
> // Attach GstGLMemory object into buffer, timestamp the buffer and
> push it downstream
> GstBuffer* buffer = gst_buffer_new();
> gst_buffer_append_memory(buffer, GST_MEMORY_CAST(glMemory));
>
> // Put timestamps into buffer
> GST_BUFFER_PTS (buffer) = timestamp;
> GST_BUFFER_DURATION (buffer) = gst_util_uint64_scale_int (1,
> GST_SECOND, 2);
>
> timestamp += GST_BUFFER_DURATION (buffer);
> GstFlowReturn ret;
> g_signal_emit_by_name(state->appsrc, "push-buffer", buffer, &ret);
>
> if (ret != GST_FLOW_OK)
> {
> // Something wrong, stop pushing.
> g_printerr("Something went wrong: Pushing buffer into appsrc
> is stopped.\n");
> return false;
> }
>
> return true;
> }
> /
>
> pushFrame produces the following error:
> gst_gl_context_thread_add: assertion 'context->priv->active_thread ==
> g_thread_self ()' failIed
>
> What am I doing wrong or how can push gpu texture to gstreamer?
>
> Thanks,
> Lusine
>
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