RV9 Artefacts

[daiyam]

Hello

I have encoded the clip 'On Your Mark' with the Gold Version in two pass.
But I have some artefacts.

- on the beginning, there is a black pixel in the center of the screen (in a blue sky)
- in an other scene, there is an human with white wings and on the background the blue sky with some white clouds. When the human leave a white cloud, he is surrounded by a white ring...
This artefact is not present when I encode the clip in a single pass!!

Daiyam

PS: Sorry for the desciption but I didn't know how can I take some screen shoots with RV9??

So Sorry for my English!!

[karl_lillevold]

In order to take a screen-shot, please do one of the following
1) disable hw acceleration in the Tools->Preferences->Hardware menu, but moving the Video Card slider all the way to the left. Remember to restore the setting when you are done.
2) open a video clip in another player than RealOne to "steal" the overlay surface before opening RealOne.

Then grab a screen-shot and post a link here, or send me a PM to get my e-mail to send it to. I would be curious to see this problem.

Thanks!

[karl_lillevold]

Daiyam was kind enough to send me the scenes where he can see those twopass and onepass differences:

It is interesting to see those
twopass and onepass differences.

You have sharp eyes! Those differences can be hard to spot.

However, looking at your filesizes, which correspond to the same
scenes for onepass and twopass, you can notice the following:

mb2 : onepass 1328 KB, twopass 662 KB
ring2 : onepass 806 KB, twopass 655 KB
black2: onepass 1168 KB, twopass 529 KB

As you can see, in twopass mode, the encoder has detected that it can
spend significantly less bits in these scenes and not lose too much
quality. However, when in some cases about 1/2 the amount of bits were
spent, there will be some differences, and I think those are the
artifacts you are seeing. Twopass will then spend more bits than
onepass in other very hard scenes.

For instance, in black2, when 1/2 the amount of bits have been spent,
some quality will be sacrificed just in those black areas. Similarly
for the mb2 scene, there are some compression artifacts in the twopass
version that are not in the onepass version. I am reasonably sure if
you examine some high action scenes closely, the onepass version
has more compression artifacts than the twopass version.

Still, since it can sometimes be harder to see differences during high
action because everything is moving so fast, and during slow scenes
you have time to examine everything, it is very hard for the twopass
choices to always be optimal, but it is trying.