[meta-freescale] QtMultimedia on i.MX6

[Robert Winkler]

On Wed, Jul 10, 2013 at 6:30 AM, Philip Craig <phil at blackmoth.com.au> wrote:

> On Wed, Jul 10, 2013 at 8:41 PM, Thomas Senyk
> <thomas.senyk at pelagicore.com> wrote:
> > On Wednesday, 10 July, 2013 20:32:05 Philip Craig wrote:
> >> I'm not sure why it needs to be imx6 specific. Doesn't the opengl API
> make
> >> it so that it doesn't need to be specific? The Qt eglfs platform is
> using
> >> the vivante opengl libraries. As I understand it, the parts that need
> to be
> >> imx6 specific are confined to the eglfs platform plugin.
> >>
> >> qt-gstreamer is at http://cgit.freedesktop.org/gstreamer/qt-gstreamer
> >
> > No. There is no vendor-independent way to map cpu/vpu based memory into
> gpu
> > (/opengl) memory.
> > Without 'mapping' one needs to copy/upload via glTexImage2D.
> > This one single line(!) consumes >100% cpu of one iMX6 core  for 1080p.
> > If you 'map' the cpu load is very easily <10%
>

I was under the same impression as Philip that OpenGL does provide the
functions glMapBuffer and glMapBufferRange.  Standard OpenGL does provide
both.
Then I checked and OpenGL ES 2.0 does not have those functions but OpenGL
ES 3.0 has the latter (
https://www.khronos.org/opengles/sdk/docs/man3/xhtml/glMapBufferRange.xml).

So to clarify, if the i.MX 6 did support OpenGL ES 3 would that qualify as
a vendor-independent way to map memory?  Sorry it's slightly unrelated I'm
just curious.


> Thanks for the explanation. Just to be sure I understand you: there is
> no standard way to allocate dma buffers, so the gpu cannot do the copy
> itself? I see that gst-plugins-gl relies on gstbufmeta from the
> gst-fsl-plugins package to determine the physical address of dma
> buffers allocated by the vpu plugin or by the v4l2src.
>
> And yes, qt-gstreamer is using glTexImage2D. I guess that could be
> patched, but then you may as well just patch QtMultimedia like you
> were planning.
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