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Posted by Citizen Bob on 12/10/06 16:19
On Sat, 9 Dec 2006 20:17:01 +0200, "Jukka Aho" <jukka.aho@iki.fi>
wrote:
>> I have an MPEG-2 clip from a VOB that is 11 minutes in duration.
>> It is 765 MB in size. The frame size is 720x480 [...] I converted
>> it into an AVI/XviD with Auto Gordian Knot [...] It looks just as
>> good in VLC on a 20" CRT monitor as the original. [...] The file
>> size is about 1/2 the original, which means I can get the same
>> content on half the number of DVDs, which is a significant savings
>> in DVD disc cost.
>Note that if your original material was shot in interlaced format, with
>an interlacing video camera (home video is usually like this) you have
>just lost half of the temporal resolution. All motion will be twice as
>juddery in the XviD file. (Converting interlaced video from 720480 to
>720400 implies deinterlacing, which typically causes this kind of
>effect - unless the frame rate is upped to the field rate in the
>conversion, which most people don't even think of doing.)
I am sure you can find examples that support your claim, just as I can
find examples that do not support your claim. The source I used in the
tests I provides was from a standard DVD.
>You probably can't see the difference on a computer screen, though.
>Computer video players will usually deinterlace interlaced material on
>the fly, anyway, so the playback of your original file is compromised as
>well - on a computer screen. But the difference should be obvious if you
>make a DVD out of the original material, play it back on a regular tv
>set, and compare that to the converted material.
I did exactly that and I could not see any loss of resolution.
>The original clip
>should have a noticeably smoother, fluider feel to it in any segment
>with fast pans or zooms, or lots of action.
The clip did have a lot of fast pans and zooms and it had a lot of
action too. But there was no jumpy action.
The newest XviD codecs are really quite good. You sound like you are
using older codecs.
--
Government's view of the economy could be summed up in a
few short phrases: If it moves, tax it. If it keeps moving,
regulate it. And if it stops moving, subsidize it.
--Ronald Reagan
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