Video display experience

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I'm looking at developing an embedded system that, amongst other
functions, will have three video feeds (from video cameras). The user
will have one display with an on-screen menu. They may choose to view
any one of the video streams or they may choose to have all 3 on the
screen at once (probably tiled as 2x2 tiles with the fourth tile
black). Does anyone have any experience (good or bad) of doing this
what chipsets did you use. We have done on-screen displays before now
so I'm really interested in technology to tile the different views on
the display.

Thanks

Iain

Iain Tebbutt

www.claritech.co.uk
Hardware and Software Design

Re: Video display experience
On 6 Aug 2003 01:31:45 -0700, snipped-for-privacy@hotmail.com (Iain Tebbutt)

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You do not say if the cameras are analog (like PAL or NTSC cameras),
or digital, like a USB webcam or a camera doing firewire (like a
camcorder).

I was looing at something similar a while back for a project that is
now deferred, but the choice of camera input seems to be crucial -
What I wanted was a graphics controller that could also take a PAL
input and merge the two, but I could not find any. I was trying to
avoid the complexity of doing MPEG decoding in my software, as I would
have to do for the digital camera solutions I was considering.
    Niall Murphy

===========================
See the User Interfaces for Embedded Systems Page
at http://www.panelsoft.com

Re: Video display experience
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I think we're really looking for analog cameras at this stage (PAL in the UK).

Thanks

Iain

www.claritech.co.uk

Re: Video display experience
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There is a device from NEC that looks similar to your requirements,
however it can only capture one video stream via an external video
processor. Have a look into the product letter at
http://www.ee.nec.de/_pdf/S16001EE1V0PL00.PDF . A datasheet is not yet
available on the internet but if you need one, I can email it to you.
Supply in Europe is established, but it may not be easily available
elsewhere, so check locally before starting a design.

Michael

Re: Video display experience
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Iain,

Have a look at Integral Technologies for a PCI frame grabber, and software.
I was working for a company in Melbourne in 2001 that were using them
for several major rail projects.

http://integraltech.securityint.com/home.cfm

--

Regards
David Milne

Re: Video display experience
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Seems like a lowcost PC motherboard could do this rather easily with a
digitiser card or a few USB cameras.

As an added bonus you can record to harddisk etc.

Ralph



Re: Video display experience
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Compressing one scanline to half it's length is indeed relative easy.
But what about the second scanline? What about the pictures you want to
place at the bottom? What about 3 camera's running asynchronous?

You still need to store the entire frame, scale it (just read and skip
odd pixels and odd lines), copy it to the screenbuffer of your output
device. No cheap analog escapes here, I'm afraid.

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No, not easy to do, without a PC.


--
Thanks,
Frank Bemelman
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Re: Video display experience
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Some years ago, a Scottish company called VLSI Vision Ltd, now aquired by
Thomson, had a CMOS image sensor which had support for this. Normally the
sensor would output one full frame of video. In the multi-sensor mode, four
sensors could be connected by parallelling their video outputs, configuring
one as master and the others as slave. A few sync signals connected
completed the setup to produce a 4-quadrant image. No extra hardware needed.
Oh, and I have some 40 lying around.... :-)

Meindert



Re: Video display experience
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Yes this is exactly what I need to do but, as you say, the problem is
that I have three asynchronous video cameras so I'd need to decode,
store the image and then decode. This is fo an application where a PC
solution would be too expensive and even a PC104 solution would
probably be too large as well.

As an aside I've found one company that seems to do the right sort of
thing at www.alogics.com - has anyone used these?

Thanks

Iain

Iain Tebbutt
www.claritech.co.uk

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