[MEncoder-users] RGB => YV12 conversion

[Rich Felker]

On Wed, Sep 28, 2005 at 09:15:16AM +0400, Vladimir Mosgalin wrote:
> Hi Rich Felker!
> 
>  On 2005.09.27 at 23:21:52 -0400, Rich Felker wrote next:
> 
> > Look up aliasing, then. It has a very precise meaning.
> 
> OK, I found this in mplayer's docs
> 
> aliasing (only downscale)
>         straight lines look like staircases
>         areas of high detail look worse
>         regular patterns turn into a funny looking mess (moire patterns)
>         bad: fast bilinear, point, gauss with low variance
>         acceptable: area
>         ok: others
> 
> staircases and moir patterns are exactly what I was talking about.

These are common symptoms to identify it by, not definitions.

> > > I prefer sharp picture with artifacts to smooth picture. Some of my
> > > friends prefer smoothed one. So what?
> > 
> > You mean to tell me a video reduced to half-height with -vf field=0
> > looks better than with a proper scaler?
> 
> No, it looks a bit worse. And aliasing effect is stronger with it (but
> when downscaling with bicubic scaler it appears _too_). But I don't
> really understand what do you want to say, that phrase of mine wasn't
> related to the rest of mail. Just an objection to your "nothing can be
> worse than <something you don't like much>".

I think if you understood sampling theory my statement would make
sense and not be so unbelievable..

Rich