[mythtv-users] Slow Performance - Improving Picture Quality

William Preston bpreston at networkusa.net
Sat Mar 22 17:49:43 UTC 2003

> Broadcast NTSC or PAL is crappy. Resolutions beyond a width
> of 480 just give a more perfect reproduction of the crappy
> picture. I believe this is why the commercial products use
> widths from 352 thru 544. Higher widths are a waste of disk
> space for no real perceivable quality improvement.

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 that
on my setup (BT878 card), using MP4, I get a better image by capturing at
720 horizontal.  Everything in the image seems a lot sharper to me.

I don't know why--maybe some quirk with the BT878 driver, something with
the nuppel codecs, maybe even something weird with my video card (G400)
scaling the output to fullscreen during playback.  I know it shouldn't be
that way, but that's just what I've observed on my system.

[disclaimer:  I haven't switched from 720 to a lower res for several
months, so it's possible it was just something in a previous CVS that was
squirrely which produced what I was seeing.]

> So, my favorite setup right now is 544x480, 4400 scaled bit
> rate. This only use ~60% CPU time on a 1.3GHz Duron. A bit
> rate of 5500 can look a little better for lots of motion but
> not enough better to justify wasting more disk space. I record
> lots of basketball games and it still looks okay despite the
> motion. The T... commercial product attached to the same TV
> has much more noticeable artifacts during basketball games.
> --  bjm
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