[mythtv-users] Re: Re: Best video capture resolution for output to TV?

[Allen T. Gilliland IV]

Well ... based on my understanding of sampling there
is no actual limit to the amount of sampling you can
do of an analog signal.  So for the purposes of our
resolution debate I would say that the higher your
horiz resolution is the better.

Of course there are mathematical formulas which detail
the suggested number of samples necessary to represent
an analog signal.  And practically speaking you
wouldn't want to exceed 720 because your playback
image would be in a strange ratio.

> But his reply got me wondering ... to what extent is
> the benefit of 
> increased horizontal dot density limited by encoding
> parameters? For 
> example, if the encoding quality is set at, say, 10
> Mb/minute, I'd expect 
> that increasing horizontal dot density will at some
> point hit the limit of 
> encoding quality (or maybe CPU speed, but let's put
> this part aside for 
> now). In such a case (if the CPU permits it), would
> increasing encoding 
> quality to, say, 20 Mb/minute allow increased
> horizontal dot density to 
> show improved quality? At what point does the
> resolution of the NTSC signal 
> *itself* impose a limit?

I don't think there is any limit on the number of
samples you can take of an analog signal.  But of
course the higher the horiz res (dot density) the more
pixels you have per frame in your video.  And so to
maintain quality you would have to increase your
bitrate as you increase resolution.  I am sure at some
point your computer wouldn't be able to handle all the
data ... at least not in real time.

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