[MEncoder-users] RGB => YV12 conversion

[Rich Felker]

On Tue, Sep 27, 2005 at 09:40:35PM +0400, Vladimir Mosgalin wrote:
> Hi Rich Felker!
> 
>  On 2005.09.27 at 12:15:04 -0400, Rich Felker wrote next:
> 
> > > > > know why you're mentioning aliasing, that has nothing to do with
> > > > > bitrate/artifacts.
> > > > 
> > > > Apparently talking about downscaling with a bad resampler...
> > > 
> > > Why bad? 2x downscaling will always either give aliasing or produce way
> > 
> > I get the impression you don't know what aliasing means..
> 
> Er, I mean - when you clearly see that line isn't smooth, but looks like
> 
>     **
>   **
> **
> 
> and other similar effects. Either this or blurring always happen when
> you downscale to small resolution and then upscale. Downscaling two
> times is enough for sharp-looking video for this effects to show.

Look up aliasing, then. It has a very precise meaning.

> > > too smooth picture, which may be better for encoding, but worse for
> > > eye...
> > 
> > Worse than aliasing? Nothing is worse than aliasing..
> 
> I thought we already concluded that we measure quality of video in a
> different way. I still don't understand what you dislike about tearing
> effect in some video out drivers, for example ;)
> 
> 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?

Rich