[XviD-devel] Qpel Problem Samples

[Christoph Lampert]

On Fri, 5 Sep 2003, Michael Militzer wrote:

> Hi,
> 
> Quoting Christoph Lampert <chl at math.uni-bonn.de>:
> 
> > thanks for the samples and detailed description. We'll check... So far we
> > know that _if_ Qpel is helpful, it already better for any short parts
> > of the video, and usually not by higher PSNR, but by lower filesize. 
> >
> > So if you want to decide on QPel/noQPel you can encode a
> > short piece (10s) from the middle with fixed quant and then decide on
> > QPel/noQpel by smaller filesize. 
> 
> I don't agree. You can't decide from just a short test sequence if qpel
> would be helpful or not for the overall clip. With 'Saving Private Ryan'
> for example, there are some scenes were qpel helps greatly and others
> where it does not help at all. I haven't checked yet if qpel is a overall
> gain or not for this movie...

Too bad, I thought it had worked for me...  :-(
Okay, then we simply do a three-pass ;-) Encode the _full_ movie at
const quant, with and without qpel, then use the better for third pass...

How needs speed anyway &*)

gruel