[MPlayer-users] mencoder with Xvid not very fast

[D Richard Felker III]

On Tue, Nov 19, 2002 at 08:28:25AM +0100, Moritz Bunkus wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> Hi.
> 
> > This is bad. Postprocessing should always be done before cropping
> > unless you really know what you're doing.
> 
> --verbose,  please. Why? Before scaling yes, but cropping only reduces
> the amount of data to be processed and leaves everything else
> untouched. Do you have an example where e.g. deinterlacing does not
> work when you crop away black bars or even part of the picture itself?

With just deinterlace it's probably not a big deal. The only possible
issue is that with an odd y offset, the deinterlacing filter has its
fields backwards, but it probably doesn't care anyway. However, if you
want to use deblocking, it's very important that macroblocks stay
lined up the same way they were decoded, and that the exported
quantizer table make it to the pp filter for the deblocker to use.
Normally this info will be lost if there are intermediate filters in
the way.

Rich