avoiding artifacts

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avoiding artifacts

Postby Nebbo » Fri Sep 06, 2002 12:29 pm

hey
is it in anyway possible to avoid compression artifacts when compressing text on a black background?
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Postby jbone » Fri Sep 06, 2002 12:44 pm

Use a high enough bitrate, proper keyframing, a proper source, etc...
"If someone feels the need to 'express' himself or herself with a huge graphical 'singature' that has nothing to do with anything, that person should reevaluate his or her reasons for needing said form of expression, possibly with the help of a licensed mental health practitioner."
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right, but

Postby Nebbo » Fri Sep 06, 2002 12:58 pm

it doesnt matter what data rate i put in
looks great in huffyuv but as soon as its compressed with a lossy
codec there's a lot of greyish flickering pixels around the text
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Postby trythil » Fri Sep 06, 2002 12:58 pm

...or don't use DivX.
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Postby jbone » Fri Sep 06, 2002 12:59 pm

Is you source a solid black image with solid-colored text on it, or are you recompressing from a previously-compressed black video image containing text? IF you're doing the latter, then odds are that the artifacting is already in the source, so you won't be able to recompress it without artifacting unless you use one or two specialized plug-ins for VirtualDub or such.
"If someone feels the need to 'express' himself or herself with a huge graphical 'singature' that has nothing to do with anything, that person should reevaluate his or her reasons for needing said form of expression, possibly with the help of a licensed mental health practitioner."
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Postby Nebbo » Fri Sep 06, 2002 1:06 pm

the source if directly from a psx game compressed with huffyuv
it's as clean as it gets
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Postby jbone » Fri Sep 06, 2002 1:22 pm

Files on PSX discs are compressed. Encoding it into Huffyuv simply prevents it from losing any further data; however, you are still reencoding from a lossy source, and thus you will need to take additional measures to prevent further artifacting.
"If someone feels the need to 'express' himself or herself with a huge graphical 'singature' that has nothing to do with anything, that person should reevaluate his or her reasons for needing said form of expression, possibly with the help of a licensed mental health practitioner."
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Postby Nebbo » Fri Sep 06, 2002 1:25 pm

yeah, ok
so what kind of measures do you suggest?
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Postby Zarxrax » Fri Sep 06, 2002 1:44 pm

Use a temporal or spatial smoothing filter in virtualdub.
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Postby The Wired Knight » Fri Sep 06, 2002 3:36 pm

Also some programs will allow you these filters on their own. virtualdub has a simple filter interface though so it should work but so do all pinnacle systems and I believe Premiere does as well.
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