[mythtv-users] Pinnacle PCTV HD Pro Stick

[Brian Phillips]

Mike Perkins wrote:
> jedi wrote:
>> 
>>    ANY digital capture solution is going to be simpler because it
>> doesn't have to digitize anything. I am not sure there is such a
>> thing as a "digital SD card" (DVB excepted). SD capture cards aren't
>> just capturing the incoming video, they are also digitizing it since
>> the stream is coming in as analog.
>> 
>>    In the US this would even be the case for "digital SD". It's going
>> to hit your system as an analog stream and get re-digitized.
>> 
>>     An HD capture card doesn't have to do much work really. The data
>> is already in a format suitable for computer consumption.
>> 
> Nope. Digital is digital, SD or HD, end of story. It does not hit
> your system as an analog stream, so does not need to get encoded. As
> I am in the UK, I don't have precise details of the
> encoding/multiplexing methods used by ATSC, so I can't possibly
> comment on whether or not a digital tuner card will be able to do
> both HD and SD, or if there are only SD cards.     

The confusion comes because SD has the connotation of being an analog
signal.  We sometimes forget to mention that 480i/p can be considered a
digital SD signal.  But that is the question we're asking of Carl L.
Gilbert.  What device is he referring to that markets itself as an SD only,
digital capture card?

We should also remember that even though QAM and ATSC carry digital signals,
they are modulated with a carrier frequecy and the symbol  signifigance
depends on the phase and amplitude of the signal at the sampling instance.
For all intents and purposes, they are an analog signal.  They just carry
modulated 1's and 0's.

Brian