[mythtv-users] Resolution

papenfuss at juneau.me.vt.edu papenfuss at juneau.me.vt.edu
Wed Dec 3 17:20:48 EST 2003


> > 	VHS also has a general problem of only providing 3MHz bandwidth, while
> > a full NTSC signal is 6MHz...  I believe this is SVHS's major improvement,
> > it provides 5MHz or more.
> 
> There you go! That's the easiest way of explaining it, rather than trivia 
> about the way VHS stores fields on tape. However it stores the video on tape, 
> VHS results in less bandwidth than needed for NTSC. And the term crosstalk is 
> when I should have been using instead of bleed.

	Actually, not to pick any more nits (seem to be lots of them on this
thread), but the 3MHz bandwidth on the tape is the fundamental limitation for
the *horizonal* resolution (i.e. "lines" of analog resolution).  The
interlacing and crosstalk stuff has more to do with the *vertical* resolution,
or rather the number of scanlines.  If the crosstalk were very appreciable,
captured video that had easily visible interlacing would show it on every other
line.  These adjacent *field* scanlines (not frame... i.e. 1-3-5-7) would bleed
together a bit.  If anything, that's all I was able to see was "a bit" of
analog ghosting/ringing between "adjacent" lines.  The VHS tape that I played
with to test the interlacing was done with SP, so it probably doesn't do as
much smearing as on LP or SLP.

	Boy... sure got myself into a mess here.  Let's all agree that VHS 
sucks... :)

-Cory

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