Re: [Discuss-gnuradio] Status of BTTV/CX88 capture

[Hew How Chee]

Hi,

I did some experiment on the CX tv card some time
back. Looks like a continuous capture of 28MHz 8 bit
data from the video ADC is possible, at least it seems
like that. I tried capturing  a sine wave and also raw
composite TV signal. However I did not proceed further
because the data looks noisy, even with no input. Not
sure whether is it cause by the  PCB layout. The sine
wave signal came from Palm since I dont have a sig
gen. As for the video signal, it came from videocam.

I deleted the capture data when I reformat the hard
disk. If anyone is interested to look at it. I can
recapture the data this weekend, hopefully I can dig
out the source code.

Regards,
HowChee



--- Martin Dvh <address@hidden> wrote:

> Cory Papenfuss wrote:
> >     Just wondering if there's been any more
> progress on that front.  A 
> > recall awhile back some promising information on
> continuous raw captures 
> > on CX88-based cards.  It would definately be an
> inexpensive way to play.
> I haven't been working on this lately.
> I still don't own a capture card with this chip.
> I did hack the cx3288 driver and others tried this
> out.
> Enabling the RAW_ALL bit didn't result in a
> continuous capture (yet).
> 
> Since there are a lot of (undocumented) registers of
> which the values are very interrelated hacking a
> driver when others have to test every 
> change goes very slow.
> 
> Of course, buying one of these for myself would
> increase the development speed but since the outcome
> might very possibly be that it cannot be 
> done I did'nt do that.
> 
> If anybody who has a capture card with this chip
> wants to go ahead and try hacking the driver further
> I would be more then willing to help.
> (My code so-far is at
>
http://www.olifantasia.com/pub/projects/gnuradio/mdvh/cx2388x/
>
http://www.olifantasia.com/pub/projects/gnuradio/mdvh/bt8x8_driver/
>
http://www.olifantasia.com/pub/projects/gnuradio/mdvh/examples/
>
http://www.olifantasia.com/pub/projects/gnuradio/doc/specsheets/
> )
> 
> Also look in the gnuradio mailing list archives for
> [Discuss-gnuradio] using ADC of a TV-card with
> CX2388x chip or digital TV-reception chips/cards
> [Discuss-gnuradio] ATTN Martin Dvh: cx8800 driver
> 
> Since recently, I own an usrp.
> I am still interested in using a hacked tv-card
> since my experiments with the hacked bttv card
> delivered  60 Msamples/sec to main memory without 
> problem.
> With the usrp I am limited to the usb2 bandwidth
> (which restricts me to 4 Msamples/sec on my pc which
> has a cheap usb2 pci add-on card).
> 
> 
> greetings,
> Martin
> 
> 
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
>
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> 


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