assrender doesn't render frames into given memory area
Submitted by Andreas Frisch
i've done some debugging and by the looks of it, the videosrc buffer data pointer
changes during this line (in gst_ass_render_chain_video):
gst_video_frame_map (&frame, &render->info, buffer, GST_MAP_WRITE);
if the rendering is supposed to be written into a specially allocated dma area, this will cause the need for an extra memcpy.
this may be a general gst_video_frame_map problem or just me not correctly understanding yet, how this works.