[MPlayer-users] copy DVD, then compression, produces "jumpy " and pixelated avi?

[Yang]

ok, I tried

--dumpstream

it's funny that on my laptop this produced correct result, but on another
desktop, the exact same command still produced pixelated and jumpy video.
 the file lengths are exactly the same, but contents are different. I tried
the same command twice on the problematic desktop, both times it produced
exactly the same file (binary equivalent byte by byte). I don't know why
the two  boxes produced different files. both have libdvdread4 installed.
both have the same ubuntu 14.04 and same version of mplayer/mencoder
installed.....



On Sat, Dec 27, 2014 at 7:42 AM, Reimar Döffinger <Reimar.Doeffinger at gmx.de>
wrote:

> On Sat, Dec 27, 2014 at 12:59:52AM -0800, Yang wrote:
> > I copied down my DVD by -ovc copy , so that I have an exact high-quality
> > copy of the original file.
>
> A lot can, and often will, go wrong with -ovc copy.
>
> > but the second batch of output produces very low quality, the images are
> > highly pixelated, and the big pixels seem to jump quickly; the actual
> file
> > size being generated is much much smaller than the original DVD file.
> but I
> > did manage to get the bit rate up by using mencoder options, to about
> 2000k
> > bits/sec. but even at this high bitrate, the same problem still occurs.
>
> For these use cases using bitrate is usually a bad idea. One-pass
> bitrate encoding usually will result in occasionally bad bitrate not
> matter how high you go.
> You'll rather want "constant quality". That doesn't quite exist, but
> the vqscale=... (for most codecs, 2 is a good value) or crf=... (for x264,
> pick something around maybe 18) come close.
>
> > that is wrong? I was thinking maybe on the second copy, libdvdcss is not
> > automatically invoked so the result is garbled ? I checked libdvdread/css
> > is installed correctly
>
> CSS is not involved or required after the initial copy, decrypted is
> decrypted, no point in doing that twice.
> Probably your -ovc copy didn't produce a working file.
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