[mythtv-users] Slow Performance - Improving Picture Quality

Edward Wildgoose edward.wildgoose at frmhedge.com
Sun Mar 23 08:26:12 UTC 2003

> > I know that's the theory of broadcast NTSC/PAL signals, and I know it's
> > also the reality that anything over 480 is overkill.  But I've found
> > on my setup (BT878 card), using MP4, I get a better image by capturing
> > 720 horizontal.  Everything in the image seems a lot sharper to me.
> Yes, it is going to be better. The question is if it is enough
> better to justify using the resources. If the files are
> twice as big, would someone prefer a slightly better picture
> or twice as much recording time. Since the commercial products
> advertise their recording capacity, they tend to stick to
> 'good enough' resolution.

I'm seeing the same thing on my PAL setup.  Using horizontal at 480 has a
lot of very visible artifacts and other cruft.  It is like looking at a tv
with bad reception, wavy lines, etc.  Raising to about 576 makes a dramatic
improvement in quality and going onwards to 720/768 gives a further
reasonable improvement in quality.

Curiously dropping horizonal res to less than 576 does not drop quality very
quickly.  I might have expected artifacts due to the way the de-interlacer
works to start creeping in...?  Currently 576x576 is what I am finding I
need for a high quality TV picture, I would like to go with more width but
the pc is not big enough I think (dual CPU 933Mhz intel - I think that Myth
does not take advantage of extra CPU's when encoding?)

Perhaps this is not so visible with NTSC, or perhaps it is just a feature of
whatever BT8xx chipset myself and William have (I have a leadtek 2000 XP)?

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