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Author Topic: USB VIDEO ON THE DENEB?  (Read 26755 times)

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Offline amigadave

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Re: USB VIDEO ON THE DENEB?
« on: September 03, 2008, 07:39:28 AM »
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platon42 wrote:
We're not talking about USB 1.1 full-speed. We're talking about USB 2.0 Highspeed. The Deneb is able to achieve a data rate of more than 8 MB/sec. This is surely slower by a few factors than a real Zorro III card, but still could at least be twice as fast as a Zorro II gfx board.

However, given that these adapters are normally employed on fast PCs, they usually use some kind of lossless compression on the data before sending it over the bus. If this is the case and cannot be turned off, it would really slow down the gfx update considerably.

Anyway, only a few of these adapters have been announced with Linux drivers and reverse engineering on that kind of device could be a bit arkward.

Just today, I found a better one with both digital DVI and VGA output for 70 EUR ( http://www.pearl.de/a-PX3103-1419.shtml ), but I still consider this too much for just experimenting with it (donation anyone? :) )

With "current" Amiga graphic boards having problems outputting native resolutions like 1280x1024 and higher, and no-one coping with DVI or HDMI output, an USB graphics adapter might be a solution. It wouldn't be very fast, but it would provide the resolutions (up to 1680x1050 in 24 bit).

Just my two cents.


Interesting idea.  You are saying that it might be able to run twice as fast as a PicassoII card (which is ZorroII)?  I did not realize that my Retina Z3 & PicassoIV cards are supposed to be more than twice as fast as my GVP Spectrum, or PicassoII cards.  Shows I am not using them enough to notice the difference, I will have to do something about that.  Perhaps the difference in performance is not that great, but the potential of the two different Zorro busses is?

If, and only if, you truly believe that there is a better than 50% chance of success at getting one to work on the Deneb, I will donate up to $20 US dollars through Paypal toward the purchase of a likely USB to HDMI/DVI display adapter.  If I were not broke I would buy the adapter of your choice (within reason) for you to testand  write drivers for and just ask that you return it to me when you are done, but I am retired and poor now.

I try to support as many Amiga developers as I can, in some small way.
How are you helping the Amiga community? :)
 

Offline amigadave

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Re: USB VIDEO ON THE DENEB?
« Reply #1 on: September 03, 2008, 07:45:13 AM »
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platon42 wrote:
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Darrin wrote:
Thanks for that info Chris.  I figured that if Siamese could work then there was some potential here.

I'll throw 20 Euros into the pot if you want to try.  Do we have 3 more volunteers for a worthwhile project?


Speaking about potential, I think for embedded machines without onboard gfx (aka EFIKA), an adapter that uses less than 2.5W (that's the maximum allowed for USB devices) would be better suited than a Radeon whatsoever. At least for my planned Touchscreen-Car-Computer project :-)

About that "bounty" -- even if I'd get the adapter, this would not come with an obligation to complete the project. As said above, the task would be rather complex.


I must have been typing my reply at the same time you composed the above.

I would be interested to read more about your Touchscreen-Car-Computer project.  I have one of my own, but it is just an Intel Mac Mini attached to a 7" Lilliput touchscreen and dual booting Vista and OSX.  It also has a GPS antennae so I can use it for voice command turn-by-turn directions.
How are you helping the Amiga community? :)
 

Offline amigadave

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Re: USB VIDEO ON THE DENEB?
« Reply #2 on: September 04, 2008, 08:50:43 AM »
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platon42 wrote:
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wawrzon wrote:
im just back from an electronic shop, there are a lot pci tv_cards that are advertised as equipped with hardware mpeg2 decoder for a better performance. i didnt not really found something like that among usb dongles but i cant say i really looked close.


Sending uncompressed video across an USB link easily exhausts or exceeds the raw bandwidth of 480MBit/sec. A 50Hz true color stream would be at a sustained rate of 260MBit/sec. While this is not a problem for a PCI interface, over USB this is too much.



As one of the at least two contributors from the land of NTSC to help with the purchase of the USB video adapter, I must ask a stupid question.  Will your work to write a driver include both PAL and NTSC devices.  I assume it will as it is a class of driver you will be working on, but I don't know how those things work, hence the question.

Will the driver work with just one specific adapter?  If yes, and it is a PAL adapter that we purchase for you, how will you provide a NTSC frequency driver?

Forgive me if these questions are stupid. (it won't be the first or last time I have written stupid things here) :lol:
How are you helping the Amiga community? :)