On Sat, 21 Aug 2004, Dik Takken wrote:
> On Fri, 20 Aug 2004, Steven M. Schultz wrote:
>
> > There are a few new tools/utilities that are only in the CVS version.
>
> Thanks, I got it now.
Great! I hope you didn't have too much trouble building it.
> There's just one thing I'm worried about. For testing purposes, I
> created a little ImageMagick script that generates a scrolling
> end-credits sequence. It's just a picture of 1024x5000 pixels shifted
> up a little each frame, cropped to 1024x576 pixels. When I feed the
Hmmm, ok - that's an interesting approach.
> of course due to the picking of odd/even scanlines. Could this be
> solved by having my script generate frames at half vertical resolution
> and combine *all* scanlines of frame A with *all* scanlines of frame B
But isn't that effectively halving your spatial resolution?
I don't think that will help. You're still faced with the situation
that a progressive display (computer monitor) will show only half
the lines at a time.
The choice of font can make a difference (avoid the serif fonts)
and use a bolder typeface - that will help to minimize the narrow
lines that flicker when interlaced.
> into one interlaced frame? Or will that result in flickering when viewed
> on a TV?...
> of this solution is that I loose temporal resolution. I need that
> temporal resolution to make quickly scrolling text look smoother on TV.
> Apparantly that also means that it will look worse on a CRT... Sigh...
Ok - time for a couple hints/clues:
Don't use a computer monitor for video work. If you don't have
a broadcast/production monitor then use a regular TVset
The phosphor persistence of a TV set hides most of the evils of
interlacing. The whole idea of interlacing works because of the
phosphor persistence.
Things which look great on a computer screen can look very different
on an interlaced display (a TV). For one thing TVs can not produce
as many colors as a computer screen. The other thing is the interlacing
issue you're encoutering.
> The fact that my video looks bad on my CRT is not the biggest problem (I
> know scrolling text is about as bad as things can get). I am much more
> interested in how it would look on TV. Unfortunately, I don't
> have a DVD burner yet, so I can't test this for real. How can I be sure
> that my video will look smooth on TV? When I encode my generated frames to
Do you have a video out capability? I'd hook up a TV set to the video
out and use that as the
> progressive video, it always looks perfect. I would guess that
> interlacing the frames does not change anything (apart from the frame
> rate), it's just that the video looks worse when viewed on a computer
> monitor, that's all. Is that correct?
That sums it up fairly accurately ;)
Interlacing is yet another one of those things from 60+ years that
were necessary to work around the technology limitations of the time.
On a TV set most of the problems you're seeing on a computer monitor
will not be visible. TVs are quite low bandwidth compared to
computer displays.
Interlacing cuts the spatial resolution in half but doubles the
temporal resolution. What looks really _good_ is 60 frame/sec
progressive - that is smooth and very life like looking - but it's
not something you can put on a DVD.
The other thing you need is a DVD player - but you already knew that :)
Cheers,
Steven Schultz
-------------------------------------------------------
SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media
100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33
Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift.
http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285
_______________________________________________
Mjpeg-users mailing list
[EMAIL PROTECTED]
https://lists.sourceforge.net/lists/listinfo/mjpeg-users
