2pass encdong vs. 1pass quality : what is better?

yosemite · 29th March 2002, 10:23

hi,

I thought that stuff should get an extra thread

Here in the board I've read the following:

Quote:

1pass quality is better 'couse it don't use bitrate but fixed quantizer (compression) and all frames are compressed same.

well, can u check that?

DJ Bobo · 29th March 2002, 10:45

It's very simple:

If the size doesn't matter, go for quality based 100%, you'll get the highest quality possible.

If the size matters, go for 2-pass encoding, you'll get better overall quality as the equivalent quality based setting (I mean "quality based xx%" that gives you almost the same size). Just try to lower the max quantizer a bit, 12 is a way too much, the best values are between 6 and 8. I work with 8.

yosemite · 29th March 2002, 10:48

well, and what do u mean with "1pass when size doesnt matters" ?

with which movie-size I have to calculate, when I use 1pass quality?

and if I take the 1pass quality, is the max quantizer still important?

DJ Bobo · 29th March 2002, 10:55

You can't predict size when using 1-pass quality based!

quality based encoding fixes the quantizer as shown in the scale!

yosemite · 29th March 2002, 11:04

so, and 100% 1pass quality mode is close as u can get to DVD quality?

ffroms · 29th March 2002, 11:43

Yes , but you will end up with really large file.

FFS

DJ Bobo · 29th March 2002, 11:55

Quote:

Originally posted by yosemite
so, and 100% 1pass quality mode is close as u can get to DVD quality?

Yes, but still only *near* DVD quality!

Quote:

Originally posted by fforms
but you will end up with really large file.

Not always, there are some movies and animes that are very good compressible.
Example: Arc The Lad Anime episodes.
I got the 20 minutes episodes in 576x432 @24fps encoded with quality 100% on 120 to 180MB only!
Or Coyote Ugly, the whole Movie (about 95 minutes) in 704x304 @25fps encoded with quality 100% on 1,2GB
But Dragon Ball Z Movie 5 (about 47 minutes) in 512x384 @24fps got 1,3GB.

So it depends on the movie...

yosemite · 29th March 2002, 11:59

fine !

and there's no other way to find out how much ca. file-size will be in 1pass quality mode?

DJ Bobo · 29th March 2002, 12:02

Quote:

Originally posted by yosemite
and there's no other way to find out how much ca. file-size will be in 1pass quality mode?

NO WAY!

yosemite · 29th March 2002, 12:04

so, I have to do an 8 hour "test" qith 1pass quality 100% and if it isnt good, I've to take the 2pass - that will be work *gg*

jonny · 29th March 2002, 15:59

Try this: http://forum.doom9.org/showthread.php?s=&threadid=19927

If you get more than 100% you can go with costant quality encoding (and you'll end up with an undersized movie (according to the size GKnot show))

rui · 29th March 2002, 16:43

Jonny, i have been doing some divx5 comp checks, using B-frames, and must say that my results so far agree with your findings

Maybe TheWef could use some of your work to the new Gordian Knot?

jonny · 1st April 2002, 11:45

I'll try to drop a message to TheWef to see what he think...

29th March 2002, 10:48	#3 \| Link
yosemite Half Dome - Come and see! Join Date: Dec 2001 Location: CA Posts: 227	well, and what do u mean with "1pass when size doesnt matters" ? with which movie-size I have to calculate, when I use 1pass quality? and if I take the 1pass quality, is the max quantizer still important? __________________ cu yose Yosemite National Park, CA - The greatest place on earth

29th March 2002, 11:04	#5 \| Link
yosemite Half Dome - Come and see! Join Date: Dec 2001 Location: CA Posts: 227	so, and 100% 1pass quality mode is close as u can get to DVD quality? __________________ cu yose Yosemite National Park, CA - The greatest place on earth

29th March 2002, 11:59	#8 \| Link
yosemite Half Dome - Come and see! Join Date: Dec 2001 Location: CA Posts: 227	fine ! and there's no other way to find out how much ca. file-size will be in 1pass quality mode? __________________ cu yose Yosemite National Park, CA - The greatest place on earth

29th March 2002, 12:04	#10 \| Link
yosemite Half Dome - Come and see! Join Date: Dec 2001 Location: CA Posts: 227	so, I have to do an 8 hour "test" qith 1pass quality 100% and if it isnt good, I've to take the 2pass - that will be work gg __________________ cu yose Yosemite National Park, CA - The greatest place on earth

29th March 2002, 16:43	#12 \| Link
rui Registered User Join Date: Dec 2001 Location: Portugal Posts: 730	Jonny, i have been doing some divx5 comp checks, using B-frames, and must say that my results so far agree with your findings Maybe TheWef could use some of your work to the new Gordian Knot? __________________ Rui

29th March 2002, 10:45	#2 \| Link
DJ Bobo Encoding Dinosaur! Join Date: Oct 2001 Location: Europe Posts: 1,668	It's very simple: If the size doesn't matter, go for quality based 100%, you'll get the highest quality possible. If the size matters, go for 2-pass encoding, you'll get better overall quality as the equivalent quality based setting (I mean "quality based xx%" that gives you almost the same size). Just try to lower the max quantizer a bit, 12 is a way too much, the best values are between 6 and 8. I work with 8.

29th March 2002, 10:55	#4 \| Link
DJ Bobo Encoding Dinosaur! Join Date: Oct 2001 Location: Europe Posts: 1,668	You can't predict size when using 1-pass quality based! quality based encoding fixes the quantizer as shown in the scale!

29th March 2002, 11:43	#6 \| Link
ffroms Registered User Join Date: Oct 2001 Location: Croatia Posts: 190	Yes , but you will end up with really large file. FFS

29th March 2002, 15:59	#11 \| Link
jonny Registered User Join Date: Feb 2002 Location: Italy Posts: 876	Try this: http://forum.doom9.org/showthread.php?s=&threadid=19927 If you get more than 100% you can go with costant quality encoding (and you'll end up with an undersized movie (according to the size GKnot show))

1st April 2002, 11:45	#13 \| Link
jonny Registered User Join Date: Feb 2002 Location: Italy Posts: 876	I'll try to drop a message to TheWef to see what he think...

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