[MPlayer-users] Re: Joseph's Fun of Ripping Laser Discs (Fun?)

[D Richard Felker III]

On Wed, Oct 01, 2003 at 02:11:22AM -0700, Joseph N. Hall wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> Rich,
> 
> Ah, cool, thanks.
> 
> What is it about crop that is weird? I have noticed that trying
> to combine crop and expand doesn't seem to work the way I expected.
> I was trying to add a black border by cropping and then expanding,
> and it basically seemed to have no effect.  Or is this another issue
> with crop altogether?

It should work fine. What is your particular command line that's
failing?

> Mencoder isn't particularly intuitive (not to bite the hand that
> feeds me) but in the absence of information to the contrary, one
> would think that postprocessing a cropped (smaller) image would
> make more sense.  Does pp work only at the beginning of the filter
> chain?  Uh, why?

Because deblocking and deringing are per-block operations. If you
crop first, the 8x8 blocks of the decoded mpeg video will no longer
line up with the 8x8 blocks of the cropped image, and the exported
quantizer table from the video decoder (which is needed to know what
severity of deblocking/deringing to apply) will be gone, so the
postprocess filter has to assume default values.

Rich