[MPlayer-users] Comparison of different software scaler types

[Matthias Wieser]

Am Dienstag, 14. Oktober 2003 20:26 schrieb Corey Hickey:

> Hmm, interesting... That's neat to see the differences among them. I'm
> by far not an expert on this, but, depending on your visual preference,
> the more blurring scalers can be beneficial for encoding. For example:

That might be true for realtime encoding. Otherwise a scaler, that only 
scales and a blur filter, that only blurs, might give more control and 
better results. But why not just scale down more, if you don't need the 
details, a good scaler gives?


> mencoder lotr_test.vob -vf crop=712:354:4:62,scale=688:288 -sws 10 \
> -nosound -ovc lavc -lavcopts vcodec=mpeg4:mbd=2:mv0:trell:psnr:\
> vpass=$i -o 10-"$i".avi -ofps 23.976
>
> ..results in this PSNR:
> PSNR: Y:39.90, Cb:42.81, Cr:43.68, All:40.76
>
> ..whereas changing -sws 10 to -sws 1 gives this:
> PSNR: Y:41.06, Cb:43.79, Cr:44.58, All:41.87

That only shows, that the unsharp scaled video can be reproduced better.


> In the second case, lavc can more precisely encode the data getting
> thrown at it. Here's a couple pictures:

> or, if you're lazy :)

Yes, I am.

> http://bugfood.casa-z.org/sws/159.1.png   (582k)
> http://bugfood.casa-z.org/sws/159.10.png  (582k)

I can't say which one is better. Some parts are better at the first one, 
some on the second. But that doesn't matter anyway.
Those are frames from a scene with fast movement and too little bitrate.
There you would need an even more unsharp scaler or more bitrate or a 
smaller framesize. I would go for the latter two.

Regards,
  Matthias