Modifying BT878 PCI cards

[tim_stewart]

I've just installed ZM and I'm impressed. I'll hopefully catch the thieving pikies that plague our town that think they have a god given right to take anything they wish from my work. I digress.

Right, I was just wondering if anyone has done any work on modifying cards such as the WinTV series. These cards as you will know have a TV tuner and usually one phono input. As the 878 has 4 inputs I am going to have a crack at removing the tuner and also adding another three inputs. With reprogramming the eeprom this should let me convert the card to a 4 input capture card.

I'm just pottering with it at the moment but as there is an abundance of cards on ebay for next to nothing I reckon this has to be a cheap and easy way of getting 4 port cards. I have the datasheets but before I dive in I just wondered if this has been done. Also, if anyone has a dump of a 4 input 878 card eeprom (or even a 4 port one) it should be useful. Does anyone have the eeprom.exe utility for eeprom access while its still on the card - not strictly needed but could be useful for reversal and porting.

Any info appreciated

Thanks

Tim.

[jameswilson]

wow good luck well over my head matey

[zoneminder]

I would think if you can do this successfully you will end up with a queue of people knocking at your door for a modded card!

[TomAnderson]

there is an abundance of cards on ebay for next to nothing

Sounds like you just answered your own question about the feasability of this modification. Why not just buy a 4-port card on ebay for next to nothing? I'm running two of them and they work fine (though frame rates are nothing to write home about).

[tim_stewart]

Because there is an abundance of WinTV cards and 4 input BT878 cards on ebay not 4 port BT878 cards.

Anyway. I've isolated the appropriate pins on the 878 and fed video ino then and also can select them using a TV app. It's a pity that you can only select one input at once but that wasn't the object of the exercise. The only slight problem with this particaular card I have is that one of the composite inputs looks like it is mapped through the driver to another one. By that I mean when composite 1 is selected the BT878 takes its input from composite 3. Composite 0 and 2 (and 3) when selected do what I would expect (in whatever order I tested them, can't remember now).

I either haven't got the right pin (doubtful, but then again...). Or more likely, the driver for this model card has a muxsel (or whatever ther setting is) setting particular to the cards physical pin connections and associated circutry. I've downloaded the latest source for v4l and am going to clone the settings for this card to a fictitious one and give it a false ID that I will put into the eeprom ID address of my card. I'll have a play and post results.

[zherebet]

Because there is an abundance of WinTV cards and 4 input BT878 cards on ebay not 4 port BT878 cards.

Wait - what's the difference between a 4 input and a 4 port BT878 card....Did I miss something?

[tim_stewart]

Which ever way you want to call it, both types have 4 inputs, but, one type of card can supply 1 image from 1 of the 4 inputs at a time. The other type of card can supply all 4 images at the same time.

[TomAnderson]

Which ever way you want to call it, both types have 4 inputs, but, one type of card can supply 1 image from 1 of the 4 inputs at a time. The other type of card can supply all 4 images at the same time.

Sorry to sound dense here, but I still don't get it. My cheapo ebay card will allow me to watch 4 cameras simultaneously in montage view. But that's still not a 4 port card?

[zoneminder]

The critical thing is the number of bttv chips on the card. A 4 input card with 1 chip will allow you to use all four inputs but only sequentially (though it can zip through them a couple of times a second). All the inputs also need to have the same resolution and other parameters. A 4 chip card, also with 4 inputs has one dedicated video chip per input and each is entirely independant.

[TomAnderson]

Gotcha.