[MPlayer-users] Re: RFC: docs update for "how to create a highquality DVD rip"

[Ivan Kalvachev]

D Richard Felker III said:
> On Thu, Jun 10, 2004 at 03:36:33PM +0200, Tobias Diedrich wrote:
>> D Richard Felker III wrote:
>> > Yeah, it's actually amazing how much DVDs suck. BTW for those complaining
about blocking artifacts and such in their lavc mpeg4 rips, guess what?
The original DVD has blocking too... :(
>> >
>> > The solution? Rent the film cans and use professional equipment to
capture it at hdtv res (or higher) and with 16 bit luma precision, then
make a new codec that allows 16bit luma... Or just be happy with what
you've got.
>> AFAIK mpeg2 does allow up to 10bit dc precision, but with current
hardware/software you are limited to 8bit on input and output... However I
don't know how big the difference between 8 and 10 bit really is be.
>
> Well the blocking problem seems to be that with (stupid!) video
> hardware (with improper gamma!) you can visibly see the difference between
consecutive intensity levels at 8bit precision. As long as this is true,
you're doomed to have some sort of artifact, whether it's blocking or
banding in slow gradients or whatever... A few more bits would help a lot,
but like you say everything is limited to 8.
>
> Rich

It look like you are messing something.
The 10bit DC precission is on DC component of the IDCT coeficients, And all
coefficients are 12 bits (max). As DC is coded as difference, it is not always
bad issue (e.g. it is like using quantizer 4 at worst case)

About scanning film. Yes they scan it at monster resolutions, but this is
nothing compared with postprocessing (an probably hand work - look at
filmgimp)
to remove the film grain and to sharpen the edges.

And additional bit depth is used for fixing and brightness/contrast issues.
That's why scanning is always done with more than 8 bits per channel.


Best Regards
   Ivan Kalvachev
  iive