[MEncoder-users] filesize become very big after convertion

Nicolas George nicolas.george at ens.fr
Tue Aug 22 19:34:29 CEST 2006


Le quartidi 4 fructidor, an CCXIV, Phil Ehrens a écrit :
> I haven't seem much *scaling* to that resolution, but I think that
> *cropping* to 704x384 is common (to remove black borders from 16:9
> in 4:3 letterbox) and doesn't degrade the image.

Yes, if it is cropping, it is certainly a good thing, although I doubt that
any codec will waste a lot of bits in the constant black areas.

But you must keep in mind that although DVD have a 1.25:1 or 1.5:1 aspect
pixelwise, they carry tags that indicates that they should be viewed at 4:3
or 16:9. And good DVD will not needlessly use 4:3 and encode black borders.
Therefore, when you see 704×384, it is often the result of a 704×451
cropping AND then a scaling. And this down-scaling is not always a good idea
when the bitrate is enough.

Regards,

-- 
  Nicolas George
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