[vdr] Re: Deinterlacing

["Reinhard Walter Buchner" <rw.buchner@freenet.de>]

Hi,

> Me too - and the deinterlacing is simply done by my projector -
abosolutely no
> interlacing artifacts visible. If i like to see the VGA signal i switch
the
> source (and can still have the video as overlay) else i switch to S-Video.

From the above I have to take it for granted you are running a digital
PJ ;o)) Correct? Since these types of PJ have their own problems
with artifact introduction (a simple keystone correction on a digital
PJ already kills resolution!), you'll never notice source artifacts ;o))

> BTW - how much impact has the video-cable?

Depends on the run. Anything less than 0,5m is pretty uncritical. Going
for longer lengths and you should start impedance mathing your cables.
This means 75 ohm cables and terminators. True 75 ohm BNC
connectors are a waste of money in my mind. Normal BNC are 50 ohms.
However, the wavelength of the connector is so minimal that this only
becomes important in frequencies above 2GHz.

>Which ones can be recommended?

RG-59 or for really long runs (>50m) RG-6. Since these are MIL
specs, cable manufacturer is only a matter of personal taste.

The problem with most video setups is that the driver (be it a video
graphics card or a DVB card) was never meant to drive a large capacitive
load, which is what a longer video line looks like (your talking hundreds
of pF here). The driver must be able to charge and discharge this cap. This
means a high current, low impedance driver. Many people simply boost
the signal. This is DEAD wrong. What you want is to have a 0.7Vpp signal
at the PJ. Basically this means you need a line driver or buffer amp.

Greets,
Reinhard



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