Sascha Hauer wrote:

On Tue, Dec 23, 2008 at 01:09:10PM +0300, Dmitry Krivoschekov wrote:

quoted

Robert Schwebel wrote:

quoted

On Mon, Dec 22, 2008 at 07:37:53PM +0100, Sascha Hauer wrote:

quoted

Another thing is the overlay framebuffer. I think it's mainly useful
to display video streams.

Right. The idea is that you can push a video stream into /dev/fb1 (for
example by using the gstreamer fbdev sink) while displaying widgets from
a GUI toolkit on /dev/fb0.

quoted

Maybe it's better to implement this as a v4l device as unlike the
framebuffer API the v4l API is designed to handle different image
buffers.

Huh? v4l is image-frames-to-userspace, not vice versa.

...and vice versa too, v4l2 is not about input devices only but it is
also related to output devices, v4l2 spec even has a special chapter
dedicated to overlays [1]. Moreover, you can find such a driver within
Freescale's BSP [2]. Another example is Omap's videoout driver [3].

Are you aware of any application making use of this feature?

IIRC, mplayer is able to output on a v4l2 device. Also, Freescale's
i.MX31 ADS BSP contained a bunch of V4L2 unit tests, including v4l2 output.

Dmitry


[1]
http://www.freescale.com/webapp/sps/site/overview.jsp?code=CW_BSP_ARM&fsrch=1

Sascha

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