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What are B Frames
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Debbs
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8. July 2004 @ 22:53 _ Link to this message    Send private message to this user   
Hi there,
What r B Frames, and how does it affect the movie quality? All I hear is B frames deteriorate the quality? How does 1 modify the number of B frames?

Also, how does one tweak the quality of a movie using XviD 1.0.x? it depends on the movie :-? how? what does it depend on?

thanking you in advance.
njoy!
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shiroh
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9. July 2004 @ 01:06 _ Link to this message    Send private message to this user   
in BVOPs, its better to use 2 to 3 frames 5 max, depending on the scene. set b frame sensitivity to 15.

b frames will deteriorate the quality, as it is not full quality, it just lookup the reference frame.

a dark movie will compress better than a movie that is well lit and full of details. use copressibility test, with Gknot.

movie have noise, and that is bad for compressibility, use filters, to filter it out.
avisynth is the best tool here.
Debbs
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9. July 2004 @ 03:20 _ Link to this message    Send private message to this user   
What's BVOP? Sorry, im a newbie :). Also, what dyu mean depending on the scene? Do I have to transcode the movie scene by scene :-?

What dyu mean by B frames are not full quality? Which type of frames r full quality? What happens if I set B Fraes to 0 - zero :-?

thx in adv.
Enjoy!
shiroh
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9. July 2004 @ 04:32 _ Link to this message    Send private message to this user   
I fram is full quality. like a full picture. b frame is a fragment of that, the necessary detail that will make the motion.

take it like this. in a scene where the dude talks. which part of his body is moving ? his lips, then the frame will take that moving pixels, something like that.

if you set b frame to zero then you'll get I and P frames only. b frames is good to compress the video. still pictures of it may look bad, but while motion it hardly noticeable, cause the way it is decoded.

you don't have to transcode scene by scene, what i meant is that certain parts that looks crap, like credits can be compress more, that is what the zones settings are for.

http://www.animemusicvideos.org/home/home.php

http://www.animemusicvideos.org/guides/avtech/

http://www.100fps.com/

check out the guides from this sites.
not that this sites don't have any, but these are more details info and not only steps.

This message has been edited since posting. Last time this message was edited on 9. July 2004 @ 04:45

Kingd
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9. July 2004 @ 19:14 _ Link to this message    Send private message to this user   
Debbs, check out the unofficial XViD FAQ, it explains XViD settings in great detail and also suggests settings to use for different cases, etc. It's a hell of a read but will greatly further your understanding of XViD:
http://www.vslcatena.nl/~ronald/docs/xvidfaq.html

To Defy The Laws Of Tradition.
Debbs
Junior Member
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9. July 2004 @ 22:30 _ Link to this message    Send private message to this user   
kewl. thx for all the info & pointers Shiroh & Kingd.

Really apperciate it.

njoy!
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shiroh
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10. July 2004 @ 08:18 _ Link to this message    Send private message to this user   
http://forum.doom9.org/showthread.php?s=51fe824860870f684f5e9ae5d7b4f541&threadid=78473

some b frames disc.
the dude who did the test uses 28 b frames, so don't be intimidated by the results, 2 or 3 is the sweet spot.
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